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

 package com.gaosi.util;
 /**
  * @author Qianyukun
  *
  */
 import android.graphics.Bitmap;
 import android.graphics.Bitmap.Config;
 import android.graphics.Canvas;
 import android.graphics.LinearGradient;
 import android.graphics.Matrix;
 import android.graphics.Paint;
 import android.graphics.PixelFormat;
 import android.graphics.PorterDuff.Mode;
 import android.graphics.PorterDuffXfermode;
 import android.graphics.Rect;
 import android.graphics.RectF;
 import android.graphics.Shader.TileMode;
 import android.graphics.drawable.Drawable;

 public class BitmapUtil {
     // 放大缩小图片
     public static Bitmap zoomBitmap(Bitmap bitmap, int w, int h) {
         if (bitmap == null)
             return null;
         int width = bitmap.getWidth();
         int height = bitmap.getHeight();
         Matrix matrix = new Matrix();
         float scaleWidht = ((float) w / width);
         float scaleHeight = ((float) h / height);
         matrix.postScale(scaleWidht, scaleHeight);
         Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height,
                 matrix, true);
         return newbmp;
     }

     // 将Drawable转化为Bitmap
     public static Bitmap drawableToBitmap(Drawable drawable) {
         if (drawable == null)
             return null;
         int width = drawable.getIntrinsicWidth();
         int height = drawable.getIntrinsicHeight();
         Bitmap bitmap = Bitmap.createBitmap(width, height, drawable
                 .getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                 : Bitmap.Config.RGB_565);
         Canvas canvas = new Canvas(bitmap);
         drawable.setBounds(0, 0, width, height);
         drawable.draw(canvas);
         return bitmap;
     }

     // 获得圆角图片的方法
     public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) {
         if (bitmap == null)
             return null;
         Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
                 bitmap.getHeight(), Config.ARGB_8888);
         Canvas canvas = new Canvas(output);

         final int color = 0xff424242;
         final Paint paint = new Paint();
         final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
         final RectF rectF = new RectF(rect);

         paint.setAntiAlias(true);
         canvas.drawARGB(0, 0, 0, 0);
         paint.setColor(color);
         canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
         paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
         canvas.drawBitmap(bitmap, rect, rect, paint);
         return output;
     }

     // 获得带倒影的图片方法
     public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap) {
         if (bitmap == null)
             return null;
         final int reflectionGap = 4;
         int width = bitmap.getWidth();
         int height = bitmap.getHeight();

         Matrix matrix = new Matrix();
         matrix.preScale(1, -1);

         Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, height / 2,
                 width, height / 2, matrix, false);

         Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
                 (height + height / 2), Config.ARGB_8888);

         Canvas canvas = new Canvas(bitmapWithReflection);
         canvas.drawBitmap(bitmap, 0, 0, null);
         Paint deafalutPaint = new Paint();
         canvas.drawRect(0, height, width, height + reflectionGap, deafalutPaint);

         canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

         Paint paint = new Paint();
         LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,
                 bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff,
                 0x00ffffff, TileMode.CLAMP);
         paint.setShader(shader);
         paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
         canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
                 + reflectionGap, paint);

         return bitmapWithReflection;
     }

 }

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: