1、 新建画笔 

paintCircle =new Paint();

paintCircle.setColor(Color.RED);

paintCircle.setStrokeWidth(mClockRingWidth);

paintCircle.setAntiAlias(true);

paintCircle.setStyle(Paint.Style.STROKE);

//中心圆点

paintPoint =new Paint();

paintPoint.setStyle(Paint.Style.STROKE);

paintPoint.setAntiAlias(true);

paintPoint.setStrokeWidth(10);

paintPoint.setColor(Color.RED);

//指针

paintPointer =new Paint();

paintPointer.setStyle(Paint.Style.FILL_AND_STROKE);

paintPointer.setAntiAlias(true);

paintPointer.setStrokeCap(Paint.Cap.ROUND);

//数字

paintNum =new Paint();

paintNum.setStyle(Paint.Style.FILL_AND_STROKE);

paintNum.setAntiAlias(true);

paintNum.setTextSize(28);

paintNum.setColor(Color.BLACK);

paintNum.setStrokeCap(Paint.Cap.ROUND);

2、重写onDraw（）

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

确定画布中心位置

canvas.translate(mCenterX,mCenterY);

drawCircle(canvas);

drawPoint(canvas);

drawNum(canvas);

drawPointer(canvas);

}

3、画时钟外圆及刻度

4、画 圆心

canvas.drawCircle(0,0,mClockRingWidth,paintPoint);

5、画指针

6、画 数字

7、例图

8、让指针走动

开启定时器，调用postInvalidate()