surfaceView画图

1、视图

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical"
      >

     <Button
         android:id="@+id/bt_clear"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:text="清空"
          />
     <com.zyhui.zyhsurfaceview.ZyhSurfaceView
         android:id="@+id/zyh_sfv"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         />

 </LinearLayout>

2、MainActivity

 package com.zyhui.zyhsurfaceview;

 import android.os.Bundle;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.Button;
 import android.app.Activity;

 public class MainActivity extends Activity implements OnClickListener {

     private ZyhSurfaceView zyh_sfv;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         zyh_sfv = (ZyhSurfaceView) findViewById(R.id.zyh_sfv);
         Button button = (Button) findViewById(R.id.bt_clear);
         button.setOnClickListener(this);
     }

     @Override
     public void onClick(View v) {
         zyh_sfv.clear();
     }

 }

3、自定义surfaceView控件

 package com.zyhui.zyhsurfaceview;

 import java.util.ArrayList;
 import java.util.List;
 import java.util.Random;

 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.os.Handler;
 import android.os.HandlerThread;
 import android.os.Message;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.view.MotionEvent;
 import android.view.SurfaceHolder;
 import android.view.SurfaceHolder.Callback;
 import android.view.SurfaceView;

 //====================================
 //1、继承SurfaceView
 //2、监听SurfaceView的生命周期
 //3、自定义线程
 //4、自定义线程需要的参数
 //5、监听线程的生命周期
 //6、通过SurfaceView的生命周期来执行我们的线程
 //7、添加触摸事件
 //
 //主要是通过线程把图片画进holder中，这样它就会显示出来；
 //如果直接在HandlerThread线程中更新ui控件是不行，它会报错的
 //====================================
 public class ZyhSurfaceView extends SurfaceView implements Callback {

     private DrawingThread drawingThread;

     public ZyhSurfaceView(Context context, AttributeSet attrs) {
         super(context, attrs);
         initParams();
     }

     public ZyhSurfaceView(Context context) {
         super(context);
         initParams();
     }

     private void initParams(){
         //监听SurfaceView的生命周期
         getHolder().addCallback(this);
     }

     @Override
     public void surfaceCreated(SurfaceHolder holder) {
         drawingThread = new DrawingThread(getHolder(),
                 BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher));
         drawingThread.start();
     }

     @Override
     public void surfaceChanged(SurfaceHolder holder, int format, int width,
             int height) {
         //Log.i("zyh", width + "-----" + height);
         this.drawingThread.updateSize(width, height);//更新宽和高
     }

     @Override
     public void surfaceDestroyed(SurfaceHolder holder) {
         this.drawingThread.quit();
         this.drawingThread = null;
     }

     @Override
     public boolean onTouchEvent(MotionEvent event) {
         if(event.getAction() == MotionEvent.ACTION_DOWN){
             this.drawingThread.addItem(event.getX(), event.getY());
         }
         return super.onTouchEvent(event);
     }

     //清空图片
     public void clear(){
         this.drawingThread.clear();
     }

     //自定义线程
     private class DrawingThread extends HandlerThread implements android.os.Handler.Callback{
         private static final int MSG_ADD = 101;//添加消息
         private static final int MSG_MOVE = 102;//消息移动
         private static final int MSG_CLEAR = 103;//清空

         //定义SurfaceView的宽和高
         private int drawingWidth,drawingHeight;

         //缓存视图
         private SurfaceHolder drawingHolder;
         //画笔
         private Paint paint;
         //需要绘制的图片
         private Bitmap iconBitmap;
         //图片对象数组
         private List<DrawingItem> locations;
         //更新ui的Handler
         private Handler receiver;
         //线程是否在运行
         private boolean isRunning = false;

         public DrawingThread(SurfaceHolder drawingHolder, Bitmap bitmap) {
             super("DrawingThread");
             this.drawingHolder = drawingHolder;
             this.iconBitmap = bitmap;
             this.locations = new ArrayList<DrawingItem>();
             this.paint = new Paint(Paint.ANTI_ALIAS_FLAG);
         }

         //监听线程的生命周期
         @Override
         protected void onLooperPrepared() {
             super.onLooperPrepared();
             this.receiver = new Handler(getLooper(),this);
             this.isRunning = true;
             this.receiver.sendEmptyMessage(MSG_ADD);
         }

         @Override
         public boolean quit() {
             this.isRunning = false;
             this.receiver.removeCallbacksAndMessages(null);//移除消息
             return super.quit();
         }

         public void updateSize(int width, int height){
             this.drawingWidth = width;
             this.drawingHeight = height;
         }

         public void addItem(float x, float y){
             Message msg = Message.obtain(receiver, MSG_ADD, (int)x, (int)y);
             this.receiver.sendMessage(msg );
         }

         public void clear(){
             this.receiver.sendEmptyMessage(MSG_CLEAR);
         }

         private class DrawingItem{
             private int x,y;
             private boolean isVertical,isHorizontal;
             public DrawingItem(int x, int y, boolean isVertical,
                     boolean isHorizontal) {
                 this.x = x;
                 this.y = y;
                 this.isVertical = isVertical;
                 this.isHorizontal = isHorizontal;
             }

         }

         @Override
         public boolean handleMessage(Message msg) {
             switch(msg.what){
                 case MSG_ADD:
                     Random random = new Random();
                     DrawingItem drawingItem = new DrawingItem(msg.arg1,msg.arg2,
                             random.nextBoolean(),random.nextBoolean());
                     locations.add(drawingItem);
                     break;
                 case MSG_MOVE:
                     if(!isRunning){
                         return true;
                     }
                     //获取枷锁画布
                     Canvas lockCanvas = this.drawingHolder.lockCanvas();
                     if(lockCanvas == null){
                         break;
                     }
                     lockCanvas.drawColor(Color.BLACK);
                     for(DrawingItem item : locations){
                         item.x += item.isHorizontal ? 5 : -5;
                         if(item.x > this.drawingWidth - iconBitmap.getWidth()){
                             item.isHorizontal = false;
                         }else{
                             item.isHorizontal = true;
                         }

                         item.y += item.isVertical ? 5 : -5;
                         if(item.y > this.drawingHeight - iconBitmap.getHeight()){
                             item.isVertical = false;
                         }else{
                             item.isVertical = true;
                         }

                         //绘图
                         lockCanvas.drawBitmap(iconBitmap, item.x, item.y, paint);
                     }

                     this.drawingHolder.unlockCanvasAndPost(lockCanvas);//释放
                     //Log.i("zyh", Thread.currentThread().getName());
                     break;
                 case MSG_CLEAR:
                     //清空图片
                     locations.clear();
                     break;
                 default:
                     break;
             }

             if(isRunning){
                 this.receiver.sendEmptyMessage(MSG_MOVE);//促使图片的移动
             }
             return false;
         }
     }
 }

//画图程序:handleMessage
//画出的图之所以能够显示是因为通过SurfaceView的holder来获取画布