Android画图demo

如何在图片上画画呢？这里写了一个demo，供大家参考

一、先看一眼工程结构

工程结构：

二、自定义view

这个自定义view实现了保留轨迹的功能，代码如下

package picturegame.view;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Paint.Style;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import com.winton.picturegame.R;public class GameView extends View{private Paint paint = null; //private Bitmap originalBitmap = null;//原始图private Bitmap new1Bitmap = null;private Bitmap new2Bitmap = null;private float clickX =0;private float clickY=0;private float startX=0;private float startY=0;private boolean isMove = true;private boolean isClear = false;private int color =Color.RED;//默认画笔颜色为红色private float strokeWidth =2.0f;//默认画笔粗度public GameView(Context context) {this(context,null);// TODO Auto-generated constructor stub}public GameView(Context context,AttributeSet atts) {this(context,atts,0);// TODO Auto-generated constructor stub}public GameView(Context context,AttributeSet atts,int defStyle) {super(context,atts,defStyle);// TODO Auto-generated constructor stuboriginalBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.default_pic).copy(Bitmap.Config.ARGB_8888, true);//加载一张背景new1Bitmap=originalBitmap.createBitmap(originalBitmap);}//清除函数public void clear(){isClear =true;new2Bitmap=originalBitmap.createBitmap(originalBitmap);invalidate();//重载}public void setStrokeWidth(float width){this.strokeWidth=width;initPaint();}@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stubsuper.onDraw(canvas);canvas.drawBitmap(writer(new1Bitmap),0,0, null);}@Overridepublic boolean onTouchEvent(MotionEvent event) {// TODO Auto-generated method stubclickX =event.getX();clickY=event.getY();if(event.getAction()==MotionEvent.ACTION_DOWN){isMove =false;invalidate();return true;}else if(event.getAction()==MotionEvent.ACTION_MOVE){isMove =true;invalidate();return true;}return super.onTouchEvent(event);}/** * @Title: writer * @Description: TODO(生成bitmap) * @param @param pic* @param @return    设定文件 * @return Bitmap    返回类型 * @throws */public Bitmap writer(Bitmap pic){initPaint();Canvas canvas =null;if(isClear){canvas=new Canvas(new2Bitmap);}else{canvas=new Canvas(pic);}if(isMove){canvas.drawLine(startX, startY, clickX, clickY, paint);//划线}startX = clickX;startY =clickY;if(isClear){return new2Bitmap;}return pic;}private void initPaint(){paint = new Paint();//新建画笔paint.setStyle(Style.STROKE);//设置为画线paint.setAntiAlias(true);//可以让线条圆滑一些paint.setColor(color);//设置画笔颜色paint.setStrokeWidth(strokeWidth);//设置画笔线条的粗细}/** * @Title: setColor * @Description: TODO(设置线条颜色的对外接口) * @param @param color    设定文件 * @return void    返回类型 * @throws */public void setColor(int color){this.color=color;initPaint();}}

三、主页面布局文件

主页面布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:gravity="center_horizontal"    android:orientation="vertical" >        <LinearLayout         android:layout_width="match_parent"        android:layout_height="50dp"          android:orientation="horizontal"              >       <LinearLayout            android:layout_width="0dp"           android:layout_height="match_parent"           android:layout_weight="1"           android:gravity="center"           >           <TextView                android:id="@+id/tv_30"               android:layout_width="30dp"               android:layout_height="30dp"               android:background="@drawable/bg_notifaction"               />       </LinearLayout>             <LinearLayout            android:layout_width="0dp"           android:layout_height="match_parent"           android:layout_weight="1"           android:gravity="center"           >           <TextView                android:id="@+id/tv_25"               android:layout_width="25dp"               android:layout_height="25dp"               android:background="@drawable/bg_notifaction"               />       </LinearLayout>              <LinearLayout            android:layout_width="0dp"           android:layout_height="match_parent"           android:layout_weight="1"           android:gravity="center"           >           <TextView                android:id="@+id/tv_20"               android:layout_width="20dp"               android:layout_height="20dp"               android:background="@drawable/bg_notifaction"               />       </LinearLayout>               <LinearLayout            android:layout_width="0dp"           android:layout_height="match_parent"           android:layout_weight="1"           android:gravity="center"           >           <TextView                android:id="@+id/tv_15"               android:layout_width="15dp"               android:layout_height="15dp"               android:background="@drawable/bg_notifaction"               />       </LinearLayout>                <LinearLayout            android:layout_width="0dp"           android:layout_height="match_parent"           android:layout_weight="1"           android:gravity="center"           >           <TextView                android:id="@+id/tv_10"               android:layout_width="10dp"               android:layout_height="10dp"               android:background="@drawable/bg_notifaction"               />       </LinearLayout>        <LinearLayout            android:layout_width="0dp"           android:layout_height="match_parent"           android:layout_weight="1"           android:gravity="center"           >           <TextView                android:id="@+id/tv_5"               android:layout_width="5dp"               android:layout_height="5dp"               android:background="@drawable/bg_notifaction"               />       </LinearLayout>                <LinearLayout            android:layout_width="0dp"           android:layout_height="match_parent"           android:layout_weight="1"           android:gravity="center"           >           <TextView                android:id="@+id/tv_2"               android:layout_width="2dp"               android:layout_height="2dp"               android:background="@drawable/bg_notifaction"               />       </LinearLayout>    </LinearLayout>        <picturegame.view.GameView         android:layout_width="match_parent"        android:layout_height="300dp"        android:id="@+id/gameview"        />                <Button         android:layout_width="200dp"        android:layout_height="80dp"        android:text="clear"        android:textColor="@color/black"        android:id="@+id/btn_clear"                /></LinearLayout>

四、主Activity代码

package com.winton.picturegame;import picturegame.view.GameView;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;import com.winton.basemodule.BaseActivity;public class MainActivity extends BaseActivity implements OnClickListener {private GameView gameview = null;private Button clear = null;private TextView tv30,tv25,tv20,tv15,tv10,tv5,tv2;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);}@Overridepublic void initView() {// TODO Auto-generated method stubsetContentView(R.layout.activity_main);gameview=(GameView)findViewById(R.id.gameview);clear =(Button)findViewById(R.id.btn_clear);tv30=(TextView)findViewById(R.id.tv_30);tv25=(TextView)findViewById(R.id.tv_25);tv20=(TextView)findViewById(R.id.tv_20);tv15=(TextView)findViewById(R.id.tv_15);tv10=(TextView)findViewById(R.id.tv_10);tv5=(TextView)findViewById(R.id.tv_5);tv2=(TextView)findViewById(R.id.tv_2);}@Overridepublic void initListener() {// TODO Auto-generated method stubclear.setOnClickListener(this);tv30.setOnClickListener(this);tv25.setOnClickListener(this);tv20.setOnClickListener(this);tv15.setOnClickListener(this);tv10.setOnClickListener(this);tv5.setOnClickListener(this);tv2.setOnClickListener(this);}@Overridepublic void initData() {// TODO Auto-generated method stub}@Overridepublic void onClick(View v) {// TODO Auto-generated method stubif(v==clear){gameview.clear();return;}if(v==tv30){gameview.setStrokeWidth(30f);return;}if(v==tv25){gameview.setStrokeWidth(25f);return;}if(v==tv20){gameview.setStrokeWidth(20f);return;}if(v==tv15){gameview.setStrokeWidth(15f);return;}if(v==tv10){gameview.setStrokeWidth(10f);return;}if(v==tv5){gameview.setStrokeWidth(5f);return;}if(v==tv2){gameview.setStrokeWidth(2f);return;}}}

五、效果

运行效果图如下

六、疑问

当线条变粗时，线条会出现如上图中不连续的问题。请问高手这个怎么处理呢？我猜测应该要运行算法，但还不知道怎么运行。