與自定義view繪圖進行對比：

1.view繪圖沒有雙緩衝機制，而surfaceview有

2.view繪圖更新時，要全部更新整張圖片，而surfaceview可以更新部分割槽域

3.新執行緒無法直接更新view繪圖，需要handler配合。

魚兒遊動的動畫:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <com.example.liuyan.testbutfly.FishView
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>
 

public class FishView extends SurfaceView implements SurfaceHolder.Callback{
    private SurfaceHolder holder;
    private UpdateViewThread updatethread;
    private boolean hasSurface;
    private Bitmap back;
    private Bitmap[] fishs;
    private int fishIndex = 0;//繪製第幾張魚
    //魚的初始位置
    private float fishx = 778;
    private float fishy = 500;
    private float fishSpeed = 6; //魚的遊動速度
    //魚的遊動角度
    private int fishAngle = new Random().nextInt(60);
    Matrix matrix = new Matrix();

    public FishView(Context context) {
        super(context);
        Log.i("mydate" , "開始");
        //獲取surfaceview的surfaceholder，並將該類的例項作為其callback
        holder = getHolder();
        holder.addCallback(this);//以自身作為callback,回撥方法
        hasSurface = false;
        back = BitmapFactory.decodeResource(context.getResources() , R.drawable.fishbg);//背景
        int[] id = new int[]{R.drawable.fish0 , R.drawable.fish1 , R.drawable.fish2 ,R.drawable.fish3 ,R.drawable.fish4 ,R.drawable.fish5 ,R.drawable.fish6 ,R.drawable.fish7 ,R.drawable.fish8, R.drawable.fish9};
        fishs = new Bitmap[10];
        //初始化 魚遊動的10張圖
        for (int i = 0 ; i < 10 ; i++){
            try {
                fishs[i] = BitmapFactory.decodeResource(context.getResources() , id[i]);
            } catch (Exception e){
                e.printStackTrace();
            }
        }
        Log.i("mydate" , "結束");
    }

    public FishView(Context context, AttributeSet attrs) {
        super(context, attrs);
        Log.i("mydate" , "開始");
        //獲取surfaceview的surfaceholder，並將該類的例項作為其callback
        holder = getHolder();
        holder.addCallback(this);//以自身作為callback,回撥方法
        hasSurface = false;
        back = BitmapFactory.decodeResource(context.getResources() , R.drawable.fishbg);//背景
        int[] id = new int[]{R.drawable.fish0 , R.drawable.fish1 , R.drawable.fish2 ,R.drawable.fish3 ,R.drawable.fish4 ,R.drawable.fish5 ,R.drawable.fish6 ,R.drawable.fish7 ,R.drawable.fish8, R.drawable.fish9};
        fishs = new Bitmap[10];
        //初始化 魚遊動的10張圖
        for (int i = 0 ; i < 10 ; i++){
            try {
//                int fishId = (Integer) R.drawable.class.getField("fish" + i).get(null);//反射機制獲取圖片
//                Log.i("mydate" , "  "+ fishId);
                fishs[i] = BitmapFactory.decodeResource(context.getResources() , id[i]);
            } catch (Exception e){
                e.printStackTrace();
            }
        }
        Log.i("mydate" , "結束");
    }


    public void resume(){
        //建立和啟動 圖片更新執行緒
        if (updatethread == null){
            updatethread = new UpdateViewThread();
            if (hasSurface == true){
                updatethread.start();
            }
        }
    }

    public void pause(){
        //停止 影象更新執行緒
        if (updatethread != null){
            updatethread.requestExitAndWait();
            updatethread = null;
        }
    }


    @Override
    public void surfaceCreated(SurfaceHolder holder) { //surfaceview被建立時回撥該方法
        hasSurface = true;
        resume(); //開啟執行緒更新
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {//surfaceview改變時回撥該方法
        if (updatethread != null){
            updatethread.onWindowResize(width , height);
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {//surfaceview銷燬時回撥該方法
        hasSurface = false;
        pause(); //停止執行緒更新
    }

    class UpdateViewThread extends Thread{
        //定義影象是否更新完成的標誌
        private boolean done;

        public UpdateViewThread() {
            super();
            done = false;
        }

        @Override
        public void run() {
            SurfaceHolder surfaceholder = holder;
            //迴圈繪製，直到執行緒停止
            while (!done){
                Canvas canvas = surfaceholder.lockCanvas();//鎖定surfaceview,準備繪製
                //繪製背景
                canvas.drawBitmap(back , 0 , 0 , null);
                //魚游出螢幕外，重新初始化魚的位置
                if (fishx < 0 ){
                    fishx = 778;
                    fishy = 500;
                    fishAngle = new Random().nextInt(60);
                }
                if (fishy < 0){
                    fishx = 778;
                    fishy = 500;
                    fishAngle = new Random().nextInt(60);
                }
                //用matrix控制魚的旋轉角度和位置
                matrix.reset();
                matrix.setRotate(fishAngle);//下面的位置計算看圖片的解釋如下：
                matrix.postTranslate(fishx -= fishSpeed * Math.cos(Math.toRadians(fishAngle)) , fishy -= fishSpeed * Math.sin(Math.toRadians(fishAngle)));
                canvas.drawBitmap(fishs[fishIndex++%fishs.length] , matrix , null);
                surfaceholder.unlockCanvasAndPost(canvas);//解鎖canvas，渲染繪製圖像
                try {
                    Thread.sleep(60);
                } catch (Exception e){
                    e.printStackTrace();
                }
            }
        }

        public void requestExitAndWait() {
            //將繪製執行緒 標記為完成 ,併合併到主執行緒中
            done = true;
            try {
                join();
            } catch (Exception e){
                e.printStackTrace();
            }
        }

        public void onWindowResize(int width, int height) {
            //處理surfaceview的大小改變事件
        }
    }

}
 

位置計算圖片解釋如下:

Math.toRadians(fishAngle)

先理解這句程式碼的意思:將0-360的角度制角度轉化為pi弧度制角度

魚兒不停的遊動，座標改變其實就是：

當前的x座標 - 速度*cos角度 ， 當前的y座標 - 速度*sin角度