android实现circle Imageview

package com.czl.view;import android.annotation.SuppressLint;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.PaintFlagsDrawFilter;import android.graphics.PorterDuff.Mode;import android.graphics.PorterDuffXfermode;import android.graphics.Rect;import android.graphics.drawable.BitmapDrawable;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.widget.ImageView;/** * 圆形的Imageview *  */public class CircleImageView extends ImageView {private Paint paint = new Paint();public CircleImageView(Context context) {super(context);}public CircleImageView(Context context, AttributeSet attrs) {super(context, attrs);}public CircleImageView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);}@SuppressLint("DrawAllocation")@Overrideprotected void onDraw(Canvas canvas) {Drawable drawable = getDrawable();if (null != drawable) {Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();Bitmap b = toRoundCorner(bitmap, 14);paint.reset();// 实现了图片的自适应，需要指明imageveiw的尺寸大小canvas.drawBitmap(b, new Rect(0, 0, b.getWidth(), b.getHeight()),new Rect(0, 0, getWidth(), getHeight()), paint);} else {super.onDraw(canvas);}}private Bitmap toRoundCorner(Bitmap bitmap, int pixels) {Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),bitmap.getHeight(), Config.ARGB_8888);Canvas canvas = new Canvas(output);final int color = 0xff424242;final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());// 抗锯齿paint.setAntiAlias(true);canvas.drawARGB(0, 0, 0, 0);paint.setColor(color);int x = bitmap.getWidth();// 抗锯齿canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG| Paint.FILTER_BITMAP_FLAG));canvas.drawCircle(x / 2, x / 2, x / 2, paint);paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));canvas.drawBitmap(bitmap, rect, rect, paint);return output;}}