目录

2、 使用SurfaceView画2D图

范例一

设计GameLoop(把小线程移出来)

范例二

2、 使用SurfaceView画2D图

范例一

• 以SurfaceView绘出Bitmap图像
• 设计SpriteView类别来实作SurfaceHolder.Callback接口
• 首先来看个简单的程序，显示出一个Bitmap图像。这个图像就构成Sprite动画的基本图形。这个图像如下：
  

// SpriteView.java
// ………
public class SpriteView implements SurfaceHolder.Callback{
    private SpriteThread sThread;
    private Paint paint;
    private Bitmap bm;
    public SpriteView(Bitmap bmp) { bm = bmp; }
    @Override public void surfaceCreated(SurfaceHolder holder) {
        sThread = new SpriteThread(holder, this);
        sThread.start();
    }

    @Override public void surfaceDestroyed(SurfaceHolder holder) {}
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format,int width, int height) {}
    protected void onDraw(Canvas canvas) {
    paint= new Paint();
    canvas.drawColor(Color.WHITE);
    canvas.drawBitmap(bm, 10, 10, paint);
}

public class SpriteThread extends Thread{
    private SpriteView mView;
    private SurfaceHolder mHolder;
    private Canvas c;
    SpriteThread(SurfaceHolder h, SpriteView v){
        mHolder = h mView = v;
    }

    public void run(){
        try{
            c = mHolder.lockCanvas(null);
            synchronized (mHolder){
            mView.onDraw(c);
            }
        }finally{
            if(c!=null)
            mHolder.unlockCanvasAndPost(c);
        }
    }
}

设计GameLoop(把小线程移出来)

// SpriteView.java
// ……..
public class SpriteView implements SurfaceHolder.Callback{
    private SpriteThread sThread;
    private Paint paint;
    private Bitmap bm;
    public SpriteView(Bitmap bmp) { bm = bmp; }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        sThread = new SpriteThread(holder, this);
        sThread.start();
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder)
    { }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,int height) { }
    protected void onDraw(Canvas canvas) {
        paint= new Paint();
        canvas.drawColor(Color.WHITE);
        canvas.drawBitmap(bm, 10, 10, paint);
    }
}

// SpriteThread.java
//……….
public class SpriteThread extends Thread {
    private SpriteView mView;
    private SurfaceHolder mHolder;
    private Canvas c;
    SpriteThread(SurfaceHolder h, SpriteView v){
        mHolder = h; mView = v;
    }

    public void run(){
        try{
            c = mHolder.lockCanvas(null);
            synchronized (mHolder){ mView.onDraw(c); }
        }finally{
            if(c!=null){ mHolder.unlockCanvasAndPost(c); }
        }
    }
}

// myActivity.java
// ……..
public class myActivity extends Activity implements OnClickListener {
    private SurfaceView sv = null;
    private Button ibtn;
    private Bitmap bm;
    private SpriteView spView;

    @Override 
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        sv = new SurfaceView(this);
        bm = BitmapFactory.decodeResource(
        getResources(), R.drawable.walk_elaine);
        spView = new SpriteView(bm);
        sv.getHolder().addCallback(spView);

        LinearLayout.LayoutParams param = new LinearLayout.LayoutParams(200, 200);
        param.topMargin = 10; param.leftMargin = 10;
        layout.addView(sv, param);
        //----------------------------------------------
        ibtn = new Button(this); ibtn.setOnClickListener(this);
        ibtn.setText("Exit");
        ibtn.setBackgroundResource(R.drawable.gray);
        LinearLayout.LayoutParams param1 = new LinearLayout.LayoutParams(200, 65);
        param1.topMargin = 10; param1.leftMargin = 10;
        layout.addView(ibtn, param1);
        setContentView(layout);
    }
    public void onClick(View v) { finish(); }
}

范例二

• 让图像在SurfaceView里旋转
  

• 在MySurfaceView里定义一个DrawThread类，它诞生一个单独的线程来执行画图的任务。
• 当主线程侦测到绘图画面(Surface)被开启时，就会诞生DrawThread对象，启动新线程去画图。
• 一直到主要线程侦测到绘图画面被关闭时，就停此正在绘图的线程。
  

class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private DrawThread mThread;
    MySurfaceView(Context context) {
        super(context);
        getHolder().addCallback(this);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        mHolder = holder;
        mThread = new DrawThread();
        mThread.start(); 
    }


    public void surfaceDestroyed(SurfaceHolder holder) {
        mThread.finish();
        mThread = null;
    }

    public void surfaceChanged(SurfaceHolder holder, int format,int w, int h) { }

    class DrawThread extends Thread {
        int degree = 36;
        boolean mFinished = false;
        DrawThread() { super(); }

        @Override public void run() {
            Bitmap bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.x_xxx);
            Matrix matrix;
            degree = 0;

            while(!mFinished){
                Paint paint = new Paint(); paint.setColor(Color.CYAN);
                Canvas cavans = mHolder.lockCanvas();
                cavans.drawCircle(80, 80, 45, paint);
                //------ rotate -----------------------------
                matrix = new Matrix(); matrix.postScale(1.5f, 1.5f);
                matrix.postRotate(degree);
                Bitmap newBmp= Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(),
                bmp.getHeight(), matrix, true);
                cavans.drawBitmap(newBmp, 50, 50, paint);
                mHolder.unlockCanvasAndPost(cavans);
                degree += 15;
                try { Thread.sleep(100);
                } catch (Exception e) {}
            }
        }
        void finish(){ mFinished = true; }
    }
}

// ac01.java-
//……..
public class ac01 extends Activity {
    @Override protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        MySurfaceView mv = new MySurfaceView(this);
        LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        LinearLayout.LayoutParams param = new LinearLayout.LayoutParams(200, 150);
        param.topMargin = 5;
        layout.addView(mv, param);
        setContentView(layout);
    }
}