public class AlarmClockView extends View {

     private static final PorterDuff.Mode MODE = PorterDuff.Mode.DST_OUT;

     /**

      * 屏幕适应性参数

      */

     private static final float BIG_RADIU = 1 / 6F;

     private static final float SMALL_RADIU = 1 / 12F;

     private static final float CLOCKWISE_LENGTH = 1 / 10F;

     private static final float MINUTE_LENGTH = 1 / 12f;

     private static final float MASK_RADIU = 1 / 4F;

     // 大圆盘圈

     private Paint mPaint;

     // 指针Paint

     private Paint zhenPaint;

     // 小圆Paint

     private Paint smallCirclePaint;

     private Path path;

     private int screenW, screenH;

     /**

      * 大圆半径

      *

      * @param context

      */

     private float radius_big, small_radiu, clockwise_length, minute_length,

             mask_radiu;

     public AlarmClockView(Context context) {

         super(context);

     }

     public AlarmClockView(Context context, AttributeSet attrs) {

         super(context, attrs);

         mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

         mPaint.setStyle(Paint.Style.STROKE);

         mPaint.setColor(Color.WHITE);

         mPaint.setStrokeWidth(40);

         zhenPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

         zhenPaint.setStyle(Paint.Style.STROKE);

         zhenPaint.setColor(Color.WHITE);

         zhenPaint.setStrokeWidth(20);

         smallCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);

         smallCirclePaint.setStyle(Paint.Style.FILL);

         smallCirclePaint.setColor(Color.WHITE);

         screenW = new MeasureUtil().getWindowWidth(context);

         screenH = new MeasureUtil().getWindowHeigh(context);

         int size = Math.min(screenW, screenH);

         radius_big = size * BIG_RADIU;

         small_radiu = size * SMALL_RADIU;

         clockwise_length = size * CLOCKWISE_LENGTH;

         minute_length = size * MINUTE_LENGTH;

         mask_radiu = size * MASK_RADIU;

         // 设置指针

         path = new Path();

         path.moveTo(screenW / 2, screenH / 2 + 10);

         path.lineTo(screenW / 2, screenH / 2 - clockwise_length + 10);

         path.moveTo(screenW / 2 - 10, screenH / 2 + 10);

         path.lineTo(screenW / 2 + minute_length, screenH / 2 + 10);

     }

     @Override

     protected void onDraw(Canvas canvas) {

         super.onDraw(canvas);

         canvas.drawColor(Color.argb(255, 255, 128, 103));

         canvas.drawCircle(screenW / 2, screenH / 2, radius_big, mPaint);

         canvas.drawPath(path, zhenPaint);

         // 画耳朵圆

         drawEarCircle(canvas, 30);

         drawEarCircle(canvas, -30);

     }

     private void drawEarCircle(Canvas canvas, int degree) {

         int layerID = canvas.saveLayer(0, 0, screenW, screenH, null,

                 Canvas.ALL_SAVE_FLAG);

         canvas.rotate(degree, screenW / 2, screenH / 2);

         canvas.drawCircle(screenW / 2, screenH / 2 - radius_big - small_radiu,

                 small_radiu, smallCirclePaint);

         // 用一个大圆去遮罩

         PorterDuffXfermode xfermode = new PorterDuffXfermode(MODE);

         smallCirclePaint.setXfermode(xfermode);

         canvas.drawCircle(screenW / 2, screenH / 2, mask_radiu,

                 smallCirclePaint);

         smallCirclePaint.setXfermode(null);

         canvas.restoreToCount(layerID);

     }

 }