自定义EditText—带有清除功能，在显示多行文本时清除按钮位于整个EditText的右下角

来源：互联网发布：java基础知识大全编辑：程序博客网时间：2024/06/08 01:07

自定义带有清除功能的EditText不难，网上很多源码。简单来说，就是检测用户touch的位置，如果落在清除图标里面，则触发清除。这个清除图标是通过android:drawRight设置的。在EditText只有一行文本的时候，一切正常。可是如果EditText有多行文本时，清除图标就显示在中间（如下图）。

显然，清除图标显示在右下角更加合理。我定义了一个EditText来实现这个效果。效果图如下。实现思路是，抛弃使用drawRight来显示清除图标。而是直接在onDraw函数中绘制清除图标。这么做是因为drawRight的位置不好控制，看了下TextView的onDraw函数，想要改变drawRight的绘制位置很难。要特别说明的是，我是通过android:drawRight来获得清除图标的，获得之后即把drawRight设为null了，这样可以不用自定义属性了。

完整源码

package com.example.widget;import android.content.Context;import android.graphics.Canvas;import android.graphics.drawable.Drawable;import android.text.InputType;import android.util.AttributeSet;import android.view.MotionEvent;import android.widget.EditText;public class EditTextWithClear extends EditText {private Drawable drawableRight;private boolean showClearIcon;public EditTextWithClear(Context context) {super(context);}public EditTextWithClear(Context context, AttributeSet attrs) {super(context, attrs);}public EditTextWithClear(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);}@Overrideprotected void onFinishInflate() {super.onFinishInflate();Drawable[] drawables = getCompoundDrawables();// Store drawableRightdrawableRight = drawables[2];setCompoundDrawablesWithIntrinsicBounds(drawables[0], drawables[1],null, drawables[3]);}@Overrideprotected void onTextChanged(CharSequence text, int start,int lengthBefore, int lengthAfter) {super.onTextChanged(text, start, lengthBefore, lengthAfter);if (0 == text.length()) {showClearIcon = false;} else {showClearIcon = true;}}@Overridepublic boolean onTouchEvent(MotionEvent event) {if (event.getAction() == MotionEvent.ACTION_UP&& showClearIcon&& drawableRight != null&& event.getX() >= (getWidth()- drawableRight.getIntrinsicWidth() - getPaddingRight())&& event.getY() >= (getHeight()- drawableRight.getIntrinsicHeight() - getPaddingBottom())) {setText("");int cacheInputType = getInputType();setInputType(InputType.TYPE_NULL);super.onTouchEvent(event);setInputType(cacheInputType);return true;}return super.onTouchEvent(event);}@Overrideprotected void onDraw(Canvas canvas) {if (showClearIcon && drawableRight != null) {float dy = getHeight() - drawableRight.getIntrinsicHeight()- getPaddingBottom();float dx = getWidth() - drawableRight.getIntrinsicWidth()- getPaddingRight();canvas.save();canvas.translate(dx, dy);drawableRight.draw(canvas);canvas.restore();}super.onDraw(canvas);}}

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