这个类可以实现圆角，或者是圆形图片的操作。
CircleImageManager.java
package com.kale.utils;import android.content.Context;import android.content.res.Resources;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.PorterDuffXfermode;import android.graphics.Rect;import android.graphics.RectF;import android.graphics.Bitmap.Config;import android.graphics.PorterDuff.Mode;import android.graphics.drawable.BitmapDrawable;import android.graphics.drawable.Drawable;public class CircleImageManager { /** * @param context * 对象 * @param resId * 图片资源的id * @return 一个圆形的Drawable对象 */ public static Drawable getCircleDrawable(Context context, int resId) { Bitmap bitmap = getCircleBitmap(context, resId); Drawable drawable = new BitmapDrawable(context.getResources(), bitmap); return drawable; } /** * @param context * @param resId * @return 转换好的bitmap对象 */ public static Bitmap getCircleBitmap(Context context, int resId) { Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resId); int width = bitmap.getWidth(); int height = bitmap.getHeight(); float roundPx; float left, top, right, bottom, dst_left, dst_top, dst_right, dst_bottom; if (width <= height) { roundPx = width / 2; left = 0; top = 0; right = width; bottom = width; height = width; dst_left = 0; dst_top = 0; dst_right = width; dst_bottom = width; } else { roundPx = height / 2; float clip = (width - height) / 2; left = clip; right = width - clip; top = 0; bottom = height; width = height; dst_left = 0; dst_top = 0; dst_right = height; dst_bottom = height; } Bitmap output = Bitmap.createBitmap(width, height, Config.ARGB_8888); Canvas canvas = new Canvas(output); final Paint paint = new Paint(); final Rect src = new Rect((int) left, (int) top, (int) right, (int) bottom); final Rect dst = new Rect((int) dst_left, (int) dst_top, (int) dst_right, (int) dst_bottom); final RectF rectF = new RectF(dst); paint.setAntiAlias(true);// 设置画笔无锯齿 canvas.drawARGB(0, 0, 0, 0); // 填充整个Canvas // 以下有两种方法画圆,drawRounRect和drawCircle canvas.drawRoundRect(rectF, roundPx, roundPx, paint);// 画圆角矩形，第一个参数为图形显示区域，第二个参数和第三个参数分别是水平圆角半径和垂直圆角半径。 // canvas.drawCircle(roundPx, roundPx, roundPx, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));// 设置两张图片相交时的模式,参考http://trylovecatch.iteye.com/blog/1189452 canvas.drawBitmap(bitmap, src, dst, paint); // 以Mode.SRC_IN模式合并bitmap和已经draw了的Circle return output; } /** * 圆角的处理 * 参考：http://www.open-open.com/lib/view/open1331042856468.html * 穿入bitmap和圆角的角度（如：50） * @param bitmap */ public static Bitmap getRoundCornerBitmap(Bitmap bitmap ,int roundPixels) { // 创建一个和原始图片一样大小位图 Bitmap roundConcerImage = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888); // 创建带有位图roundConcerImage的画布 Canvas canvas = new Canvas(roundConcerImage); // 创建画笔 Paint paint = new Paint(); // 创建一个和原始图片一样大小的矩形 Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); RectF rectF = new RectF(rect); // 去锯齿 paint.setAntiAlias(true); // 画一个和原始图片一样大小的圆角矩形 canvas.drawRoundRect(rectF, roundPixels, roundPixels, paint); // 设置相交模式 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); // 把图片画到矩形去 canvas.drawBitmap(bitmap, null, rect, paint); return roundConcerImage; } /** * @param context * @param resId * @param roundPixels * @return 圆角的Drawable对象 */ public static Drawable getRoundCornerDrawable(Context context, int resId ,int roundPixels) { Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resId); bitmap = getRoundCornerBitmap(bitmap, roundPixels); Drawable drawable = new BitmapDrawable(context.getResources(), bitmap); return drawable; }}