相关疑难解决方法(0)

我正在尝试修改我用于进行相机预览的SurfaceView,以显示重叠的方块.但是,从不调用扩展SurfaceView的onDraw方法.

这是来源:

public class CameraPreviewView extends SurfaceView {

    protected final Paint rectanglePaint = new Paint();

    public CameraPreviewView(Context context, AttributeSet attrs) {
        super(context, attrs);
        rectanglePaint.setARGB(255, 200, 0, 0);
        rectanglePaint.setStyle(Paint.Style.FILL);
        rectanglePaint.setStrokeWidth(2);
    }

    @Override
    protected void onDraw(Canvas canvas){
        canvas.drawRect(new Rect(10,10,200,200), rectanglePaint);
        Log.w(this.getClass().getName(), "On Draw Called");
    }
}

public class CameraPreview extends Activity implements SurfaceHolder.Callback{

    private SurfaceHolder holder;
    private Camera camera;

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);

        // We remove the status bar, title bar and make the application fullscreen
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);

        // …