Android开发：自定义控件SurfaceView

public class MySurfaceView extends SurfaceView implements Runnable,SurfaceHolder.Callback{

    public Thread thread;
    public Canvas canvas;

    public Bitmap bitmap = Bitmap.createBitmap(80, 60, Bitmap.Config.ARGB_8888);

    public SurfaceHolder surfaceHolder;
    public Paint paint;
    public Context context;

    int map_width,map_height;

    public MySurfaceView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.surfaceHolder = this.getHolder();
        this.surfaceHolder.addCallback(this);
        this.paint = new Paint();
        this.paint.setColor(Color.YELLOW);
        this.paint.setTextSize(20);
        this.context = context;
        scale = context.getResources().getDisplayMetrics().density;

        map_width = attrs.getAttributeIntValue(null, "map_width",164);
        map_height = attrs.getAttributeIntValue(null, "map_height",160);
        Log.d("ssss", "w = " + map_width + "   h = " + map_height);


    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        Log.d("ssss", "tw = " + this.getWidth() + "   th = " + this.getHeight());
        map_height = this.getHeight();
        map_width = this.getWidth();
        setBitmap(this.bitmap);
        return super.onTouchEvent(event);
    }

    public void updataSize(){
        Log.d("ssss", "tw1 = " + this.getWidth() + "   th = " + this.getHeight());
        map_height = this.getHeight();
        map_width = this.getWidth();
        if(map_height != 0 && map_height != 0)
            setBitmap(this.bitmap);
    }


    @Override
    public void surfaceCreated(SurfaceHolder holder) {

    }

    public void setBitmap(Bitmap bitmap){
        this.bitmap = Bitmap.createScaledBitmap(bitmap, map_width, map_height, true);
        //this.bitmap = bitmap;
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        Log.d("ssss", "surfaceChanged");
        this.thread = new Thread(this);
        this.thread.start();
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        this.surfaceHolder.removeCallback(this);
        Log.d("ssss", "surfaceDestroyed");
    }

    @Override
    public void run() {
        while(true){
            synchronized (this){
                canvas = surfaceHolder.lockCanvas();
                if (bitmap != null&& canvas != null) {
                    canvas.drawColor(Color.BLACK);
                    canvas.drawBitmap(bitmap, 0, 0, paint);
                }

            }
            if(canvas != null){
                surfaceHolder.unlockCanvasAndPost(canvas);
            }
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public void setWH(float w, float h){
        this.map_width = dip2px(w);
        this.map_height = dip2px(h);

    }

    float scale;
    public int dip2px(float dpValue) {
        return (int) (dpValue * scale + 0.5f);
    }

    public float dip2px(short dpValue) {
        return (dpValue * scale + 0.5f) * 5f;
    }
}