图文详解Andorid中用Shape定义GradientDrawable

原文地址:http://blog.csdn.net/iispring/article/details/50437731

Android中提供了各种类型的Drawable，也可以用XML定义各种Drawable。本文重点讲述如何用XML中的shape节点定义GradientDrawable。

用XML定义的drawable文件放在res/drawable目录下。

用XML文件定义GradientDrawable的语法如下所示：

<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">["rectangle"</span> | "<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">oval</span>" | "<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">line</span>" | "<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">ring</span>"] ></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:topLeftRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:topRightRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottomLeftRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottomRightRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:angle</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerX</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerY</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"color"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:gradientRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"color"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">["linear"</span> | "<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">radial</span>" | "<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">sweep</span>"]        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:useLevel</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">["true"</span> | "<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">false</span>"] /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">size</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:height</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"color"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">stroke</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"color"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:dashWidth</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:dashGap</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"integer"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li></ul>

该文件以<shape>为根结点，其shape属性可取四种值：rectangle、oval、line或ring。以上语法格式中虽然列出了很多属性，但是并不是对于所有类型的shape都支持这些属性。下面分别对这四种shape进行讲解。

---

rectangle

在res/drawable下面用XML文件定义了一个名为rectangle的GradientDrawable，其对应的shape值为rectangle，表明我们定义的drawable的形状是矩形。在layout文件中定义了一个TextView，其使用了上述drawable，如下所示：

<code class="hljs perl has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><TextView android:text=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">@string</span>/hello_world"</span>        android:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"200dp"</span>        android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"100dp"</span>        android:background=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">@drawable</span>/rectangle"</span> /></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

• solid

  rectangle.xml定义如下所示：

  <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

  在上面的XML文件中，我们将shape属性设置为rectangle，我们将<solid>节点的color属性设置为绿色，<solid>属性是用来设置面的填充色的，效果如下所示： 
  

• corners 
  <corners>节点用于设置drawable四个拐角的半径，对应的XML文件如下所示：

  <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

  效果如下所示： 
  

  只有当shape属性值为rectangle时，<corners>节点才会有用。<corners>节点的radius属性同时定义了四个角的半径，如果想让这四个角的半径不一样，可以分别设置topLeftRadius、topRightRadius、bottomLeftRadius和bottomRightRadius属性，不过在设置这四个属性之前应先设置radius属性作为默认值，且默认值要大于1，无法正常使用其他四个属性。

• padding 
  <padding>节点用于设置drawable的padding，可以分别设置left、right、top、bottom四个属性，其作用与直接对TextView设置的四个paddingLeft、paddingRight、paddingTop、paddingBottom属性等价。

  XML文件如下所示：

  <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"10dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"10dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"10dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"10dp"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li></ul>

  效果如下所示： 
  

• size 
  可以用<size>节点的width和height属性设置drawable的尺寸。默认情况下，用<shape>定义的drawable会自动缩放到包含drawable的View尺寸范围。比如我们有如下的ImageView的src设置了<shape>定义的drawable，当我们设置了其scaleType值为center时，<shape>中定义的size尺寸就会限制drawable缩放。

  定义的ImageView如下所示：

  <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">ImageView</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"200dp"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_height</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"200dp"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:src</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"@drawable/rectangle"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:scaleType</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"center"</span>    /></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

  对应的drawable定义如下所示：

  <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">size</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"100dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:height</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"100dp"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul>

  效果如下所示： 
  

• stroke 
  可以用<stroke>节点设置drawable的轮廓线，通过width属性设置轮廓线的宽度，通过color属性设置轮廓线的颜色。默认情况下，<stroke>定义的是实线，除此之外，还可以设置dashWidth和dashGap属性，如果设置了这两个属性，那么就是虚线。其中，dashWidth定义了每个虚线段的长度，dashGap定义了两个虚线段之间的距离。

  对应的XML文件如下所示：

  <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">stroke</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"1dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:dashWidth</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"8dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:dashGap</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"2dp"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

  效果如下所示： 
  

• gradient 
  上面我们说到，通过<solid>可以设置drawable的颜色，但是只是一种纯色，如果想让drawable产生渐变效果，可以使用<gradient>节点创建渐变色效果。<gradient>节点具有以下属性：type、startColor、centerColor、endColor、angle、centerX、centerY、gradientRadius。其中type有三种取值：linear、radial和sweep，默认值是linear。当type取不同的值时，<gradient>并不是支持全部属性，下面详细说明。

  • linear 
    当<gradient>的type值为linear时，表示颜色是线性渐变的，此时支持startColor、centerColor、endColor、angle这四个属性，其他属性不支持。我们可以通过设置startColor和endColor指定渐变的起始颜色以及终止颜色，XML如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"linear"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>

    我们将startColor设置为红色，endColor设置为蓝色，效果如下所示： 
    

    我们还可以设置centerColor属性，指定中间色，XML如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"linear"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul>

    我们将中间色设置为绿色，效果如下所示： 
    

    默认情况下，渐变是从左向右进行的，如果想调整渐变的方向可以设置angle属性，angle的默认值为0，对应着自左向右渐变,angle的单位是角度，angle的值必须是45的倍数，否则不会有渐变效果。我们可以更改angle值，XML如下所示:

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"linear"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:angle</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"90"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

    我们将angle设置为90度，那么渐变方向就变成了从下上，效果如下所示： 
    

  • radial 
    当<gradient>的type值为radial时，表示颜色从某点向周围辐射渐变，此时支持除angle之外的其他所有属性。我们必须通过设置gradientRadius属性以指定渐变的辐射半径，通过startColor指定起始颜色，XML如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"radial"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:gradientRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"50dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>

    我们将startColor设置为红色，效果如下所示： 
    

    由上图我们可以发现，startColor（红色）从中心沿着圆的半径逐渐变淡。

    在设置了startColor的基础上，我们还可以设置centerColor，XML如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"radial"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:gradientRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"50dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul>

    效果如下图所示： 
    

    由上图可以看出，startColor（红色）从中心沿着圆的半径逐渐渐变到centerColor（绿色）。

    除了设置startColor、centerColor，还可以设置endColor，XML如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"radial"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:gradientRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"50dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

    我们将centerColor设置为绿色，效果如下所示： 
     
    由上图可以看出，startColor（红色）从中心沿着圆的半径逐渐渐变到centerColor（绿色），在指定的半径之外颜色用endColor（蓝色）填充。

    其实，startColor、centerColor、endColor这三个属性可以任意组合，大家可以自己尝试一下各种组合的效果。

    默认圆心的位置处于drawable的中心，我们可以通过centerX和centerY属性改变渐变圆心的位置，centerX和centerY的取值范围都是0到1，这两个属性的默认值都是0.5，drawable的左上角的centerX和centerY的值都是0，右下角的centerX和centerY的值都是1。我们改变centerX和centerY的值，XML如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"radial"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:gradientRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"50dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerX</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"0"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerY</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"0.5"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li></ul>

    效果如下所示： 
    

  • sweep 
    当<gradient>的type值为sweep时，表示颜色是围绕中心点360度顺时针旋转的，起点就是3点钟位置。 
    我们可以只设置startColor，XML文件如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"sweep"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

    我们将startColor设置为红色，效果如下所示： 
    

    我们也可以只设置endColor，XML文件如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"sweep"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

    将endColor设置为蓝色，效果如下所示： 
    

    我们也可以只设置centerColor的值，XML文件如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"sweep"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

    将centerColor设置为绿色，效果如下所示： 
    

    我们也可以同时设置startColor、centerColor、endColor的值，XML文件如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"sweep"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul>

    将startColor、centerColor、endColor分别设置为红、绿、蓝，效果如下所示： 
    

    centerX和centerY的默认值都是0.5，表示中心点的默认位置就是drawable的中心，我们也可以更改centerX和centerY的值，从而更新中心点的位置，XML文件如下所示：

    <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span><span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"rectangle"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">corners</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:radius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">gradient</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:type</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"sweep"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:startColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#ff0000"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:endColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerX</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"0.25"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:centerY</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"0.5"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>

    我们将centerX的值设置为0.25,效果如下所示： 
    

---

oval

在res/drawable下面用XML文件定义了一个名为oval的GradientDrawable，其对应的shape值为oval，表示drawable的形状是椭圆，并将该drawable作为TextView的background。oval和rectangle的主要区别就是drawable的形状不同，大部分的节点属性的作用是相同的。

• solid 
  如同rectangle，我们可以通过solid指定drawable的颜色，XML如下所示：

  <code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"oval"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

  效果如下所示： 
  

• corners 
  当shape为oval时，不支持<corners>节点。

• padding 
  oval同样支持<padding>节点，将四个padding值设置为20dp，效果如下所示： 
  

• size 
  oval不支持<size>节点。

• stroke 
  同rectangle一样，我们也可以为oval设定<stroke>，效果如下所示： 
  

• gradient 
  oval同样支持<gradient>节点实现渐变效果，type属性也是支持linear、radial、sweep三个属性。<gradient>节点实现的渐变效果桶rectangle的渐变效果基本一样。

  • linear 
    当type为linear时，实现线性渐变效果，我们将startColor、centerColor、endColor分别设置为红、绿、蓝，并设置angle为45度，效果如下所示： 
    

  • radial 
    当type为radial时，实现放射渐变效果，我们将startColor、centerColor、endColor分别设置为红、绿、蓝，效果如下所示： 
    

  • sweep 
    当type为sweep时，表示颜色是围绕中心点360度顺时针旋转的，起点就是3点钟位置。我们将startColor、centerColor、endColor分别设置为红、绿、蓝，效果如下所示： 
    

    <gradient>节点中的多个参数组合的效果可以参见上述rectangle中的说明。

---

line

在res/drawable下面用XML文件定义了一个名为line的GradientDrawable，其对应的shape值为line，并将该drawable作为TextView的background。当shape为line时，表示drawable的形状是线，该线会分割drawable。line只支持<stroke>和<padding>两个节点，不支持其他的节点。

XML文件如下所示：

<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"line"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">stroke</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#0000ff"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"1dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:dashWidth</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"8dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:dashGap</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"2dp"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>

效果如下所示： 

---

ring

在res/drawable下面用XML文件定义了一个名为ring的GradientDrawable，其对应的shape值为ring，表示drawable的形状是圆环，并将该drawable作为TextView的background。所谓圆环就是大圆套小圆。当shape为ring时，shape有额外的四个属性可用：innerRadius、thickness、innerRadiusRatio、thicknessRatio。

需要特别注意的是，在API<=19的真机上使用shape为ring的drawable时，Android有个bug，会不显示drawable，解决办法是将shape设置useLevel属性为true。

我们通过innerRadius指定小圆的半径，通过thickness指定大圆和小圆之间的宽度。XML如下所示：

<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"ring"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:innerRadius</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"10dp"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:thickness</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:useLevel</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"false"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>

效果如下所示： 

我们还可以通过innerRadiusRatio指定小圆的半径，innerRadiusRatio的值是float类型，如果其值是9，表示小圆的半径等于TextView宽度的1/9。同样，也可以通过thicknessRatio指定大圆和小圆之间的宽度，其值类型也是float，如果值为8，则表示大小圆之间的宽度等于TextView的1/8。XML文件如下所示：

<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:shape</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"ring"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:innerRadiusRatio</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"9"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:thicknessRatio</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"8"</span>    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:useLevel</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"false"</span>></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">solid</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:color</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#00ff00"</span> /></span>    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">padding</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:left</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:right</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:top</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:bottom</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"20dp"</span> /></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">shape</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>

效果如下所示： 

如果给ring设置了<stroke>，那么大小圆都会使用该设置的轮廓线，效果如下所示： 

ring同样支持<gradient>实现渐变效果，默认type为linear，只将startColor设置为红色，效果如下所示： 

type为linear时，只将centerColor设置为绿色，效果如下所示： 

type为linear时，只将endColor设置为蓝色，效果如下所示： 

type为linear时，<gradient>也支持angle参数。大家可以自己尝试多种颜色的组合效果。

当<gradient>的type值设置为gradial时，需要指定gradientRadius属性，否则会报错。gradial并不能像上面那样实现辐射渐变效果，gradial的ring只是用startColor填充圆环的颜色，实现的效果与指定<solid>节点中的color属性相同，此处就不贴图了。

当type为sweep时，表示颜色是围绕中心点360度顺时针旋转的，起点就是3点钟位置。我们将startColor、centerColor、endColor分别设置为红、绿、蓝，效果如下所示： 

希望本文对大家用Shape定义GradientDrawable有所帮助！