<學習記錄>記錄自定義SurfaceView的一般寫法

自定義SurfaceView的一般寫法如下：

public class SurfaceViewTemplate extends SurfaceView {
    private SurfaceHolder holder;//控制surfaceView的holder

    private Canvas mCanvas;//與SurfaceHolder綁定的canvas，用於繪圖

    private boolean isRunning;//控制線程是否運行

    private Thread thread;//繪圖Thread

    public SurfaceViewTemplate(Context context) {
        this(context,null);
    }

    public SurfaceViewTemplate(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }

    public SurfaceViewTemplate(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        holder=getHolder();
        holder.addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder surfaceHolder) {
                isRunning=true;
                thread=new Thread(){
                    @Override
                    public void run() {
                        while(isRunning){
                            draw();
                        }
                    }
                };
                thread.start();
            }

            @Override
            public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

            }

            @Override
            public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
                isRunning=false;
            }
        });

        holder.setFormat(PixelFormat.TRANSLUCENT);//設置畫布背景半透明

        setZOrderOnTop(true);//設置置頂
        setFocusable(true);
        setFocusableInTouchMode(true);
        setKeepScreenOn(true);

    }

    private void draw() {
        try {
            mCanvas=holder.lockCanvas();
            if(mCanvas!=null){
                //draw something
            }
        } finally {
            holder.unlockCanvasAndPost(mCanvas);
        }
    }


}