Android自定义Drawable实现圆角效果

package com.mydrawable.musk;import android.graphics.Bitmap;import android.graphics.BitmapShader;import android.graphics.Canvas;import android.graphics.ColorFilter;import android.graphics.Paint;import android.graphics.PixelFormat;import android.graphics.Shader;import android.graphics.drawable.Drawable;public class CircleDrawable extends Drawable { private Paint mPaint; private int mWidth; private Bitmap mBitmap; public CircleDrawable(Bitmap bitmap) { mBitmap = bitmap; //着色器，设置横向和纵向的着色模式为平铺 BitmapShader bitmapShader = new BitmapShader(mBitmap,  Shader.TileMode.CLAMP, Shader.TileMode.CLAMP); mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setDither(true); mPaint.setShader(bitmapShader); mWidth = Math.min(mBitmap.getWidth(), mBitmap.getHeight()); } //绘制 @Override public void draw(Canvas canvas) { canvas.drawCircle(mWidth / 2, mWidth / 2, mWidth / 2, mPaint); } //设置透明度值 @Override public void setAlpha(int alpha) { mPaint.setAlpha(alpha); } //设置颜色过滤器 @Override public void setColorFilter(ColorFilter colorFilter) { mPaint.setColorFilter(colorFilter); } //返回不透明度 @Override public int getOpacity() { return PixelFormat.TRANSLUCENT; } //返回图片实际的宽高 @Override public int getIntrinsicWidth() { return mWidth; } @Override public int getIntrinsicHeight() { return mWidth; }}