Android空心圆及层叠效果实现代码

package com.bwei.test.zidingyiview2;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.View;public class MyView extends View { private Context mcontext; private Paint mpaint; public MyView(Context context) {  super(context); } public MyView(Context context, AttributeSet attrs) {  super(context, attrs); } public MyView(Context context, AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr);  this.mcontext = context; } @Override protected void onDraw(Canvas canvas) {  super.onDraw(canvas);//  得到屏幕宽高  float wi = canvas.getWidth() / 2;  float he = canvas.getHeight() / 2;//  创建第一个画笔  Paint pa = new Paint();//  上色  pa.setColor(Color.GREEN);//  显示圆边  pa.setAntiAlias(true);//  设置空心圆环  pa.setStyle(Paint.Style.STROKE);//  设置圆环宽度  pa.setStrokeWidth(6);  Paint pa2 = new Paint();  pa2.setColor(Color.BLUE);  pa2.setAntiAlias(true);  Paint pa3 = new Paint();  pa3.setColor(Color.BLACK);  pa3.setAntiAlias(true);//  画什么圆  canvas.drawCircle(wi-85, he-85, 80, pa2);  canvas.drawCircle(wi, he, 100, pa);  canvas.drawCircle(wi+110, he+110, 120, pa3); }}