imageview圆角的实现

介绍一种简单的、另类的实现，就是把图片在显示前处理成圆角的，但是不改变存储的图片。相当于经过了图像过滤。
需要调用的图像工具类是
  1 package com.gaosi.util;
  2 /**
  3  * @author Qianyukun
  4  *
  5  */
  6 import android.graphics.Bitmap;
  7 import android.graphics.Bitmap.Config;
  8 import android.graphics.Canvas;
  9 import android.graphics.LinearGradient;
 10 import android.graphics.Matrix;
 11 import android.graphics.Paint;
 12 import android.graphics.PixelFormat;
 13 import android.graphics.PorterDuff.Mode;
 14 import android.graphics.PorterDuffXfermode;
 15 import android.graphics.Rect;
 16 import android.graphics.RectF;
 17 import android.graphics.Shader.TileMode;
 18 import android.graphics.drawable.Drawable;
 19 
 20 public class BitmapUtil {
 21     // 放大缩小图片
 22     public static Bitmap zoomBitmap(Bitmap bitmap, int w, int h) {
 23         if (bitmap == null)
 24             return null;
 25         int width = bitmap.getWidth();
 26         int height = bitmap.getHeight();
 27         Matrix matrix = new Matrix();
 28         float scaleWidht = ((float) w / width);
 29         float scaleHeight = ((float) h / height);
 30         matrix.postScale(scaleWidht, scaleHeight);
 31         Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height,
 32                 matrix, true);
 33         return newbmp;
 34     }
 35 
 36     // 将Drawable转化为Bitmap
 37     public static Bitmap drawableToBitmap(Drawable drawable) {
 38         if (drawable == null)
 39             return null;
 40         int width = drawable.getIntrinsicWidth();
 41         int height = drawable.getIntrinsicHeight();
 42         Bitmap bitmap = Bitmap.createBitmap(width, height, drawable
 43                 .getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
 44                 : Bitmap.Config.RGB_565);
 45         Canvas canvas = new Canvas(bitmap);
 46         drawable.setBounds(0, 0, width, height);
 47         drawable.draw(canvas);
 48         return bitmap;
 49     }
 50 
 51     // 获得圆角图片的方法
 52     public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) {
 53         if (bitmap == null)
 54             return null;
 55         Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
 56                 bitmap.getHeight(), Config.ARGB_8888);
 57         Canvas canvas = new Canvas(output);
 58 
 59         final int color = 0xff424242;
 60         final Paint paint = new Paint();
 61         final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
 62         final RectF rectF = new RectF(rect);
 63 
 64         paint.setAntiAlias(true);
 65         canvas.drawARGB(0, 0, 0, 0);
 66         paint.setColor(color);
 67         canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
 68         paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
 69         canvas.drawBitmap(bitmap, rect, rect, paint);
 70         return output;
 71     }
 72 
 73     // 获得带倒影的图片方法
 74     public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap) {
 75         if (bitmap == null)
 76             return null;
 77         final int reflectionGap = 4;
 78         int width = bitmap.getWidth();
 79         int height = bitmap.getHeight();
 80 
 81         Matrix matrix = new Matrix();
 82         matrix.preScale(1, -1);
 83 
 84         Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, height / 2,
 85                 width, height / 2, matrix, false);
 86 
 87         Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
 88                 (height + height / 2), Config.ARGB_8888);
 89 
 90         Canvas canvas = new Canvas(bitmapWithReflection);
 91         canvas.drawBitmap(bitmap, 0, 0, null);
 92         Paint deafalutPaint = new Paint();
 93         canvas.drawRect(0, height, width, height + reflectionGap, deafalutPaint);
 94 
 95         canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);
 96 
 97         Paint paint = new Paint();
 98         LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,
 99                 bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff,
100                 0x00ffffff, TileMode.CLAMP);
101         paint.setShader(shader);
102         paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
103         canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
104                 + reflectionGap, paint);
105 
106         return bitmapWithReflection;
107     }
108 
109 }
将要显示的图片过滤成圆角，再装载到imageview中
bitmap=BitmapUtil.getRoundedCornerBitmap(bitmap, Configs.BITMAPROUNDPX);//设置圆角角度（int）
imageview.setImageBitmap(bitmap);
效果: