View类中的Android倒计时

Question

我试图在3秒后出现一个圆圈，并在3秒后消失。

public class TestView extends View{

public TestView(Context context) {
    super(context);
    // TODO Auto-generated constructor stub
}

@Override
protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
    super.onDraw(canvas);
    canvas.drawColor(Color.RED);

    Paint circle = new Paint();
    circle.setColor(Color.BLUE);


    CountDownTimer count = new CountDownTimer(3000, 1000) {

        public void onTick(long millisUntilFinished) {

        }

        public void onFinish() {

            CountDownTimer count = new CountDownTimer(3000, 1000) {

                public void onTick(long millisUntilFinished) {
                    canvas.drawCircle(100, 100, 40, circle);

                }

                public void onFinish() {

                }

             }.start();

        }

     }.start();



}

这是完成此任务的好方法吗？ 但他让我把帆布和油漆作为最后的。我应该如何删除圆圈？