Android自定义带圆角的ImageView

package com.yizooo.yizooo.ui;
 
 
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.RectF;
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;
 
import com.lidroid.xutils.bitmap.core.AsyncDrawable;
 
 
/**
 * Created by 雪宝宝 on 2016/3/27.
 * 自定义圆角工具
 */
public class RoundImageView extends ImageView {
  private Paint paint;
 
  public RoundImageView(Context context) {
    this(context,null);
  }
 
  public RoundImageView(Context context, AttributeSet attrs) {
    this(context, attrs,0);
  }
 
  public RoundImageView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    paint = new Paint();
  }
 
  /**
   * 绘制圆角矩形图片
   */
  @Override
  protected void onDraw(Canvas canvas) {
    Drawable drawable = getDrawable();
    Bitmap bitmap = null;
    if (null != drawable && drawable instanceof BitmapDrawable ) {
      BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
       bitmap = bitmapDrawable.getBitmap();
      //Bitmap bitmap =( (BitmapDrawable)drawable).getBitmap();
      Bitmap b = getRoundBitmap(bitmap, 10);
      final Rect rectSrc = new Rect(0, 0, b.getWidth(), b.getHeight());
      final Rect rectDest = new Rect(0,0,getWidth(),getHeight());
      paint.reset();
      canvas.drawBitmap(b, rectSrc, rectDest, paint);
 
    }//防止出现类型转换异常
    else if(this.getDrawable() instanceof AsyncDrawable){
      bitmap = Bitmap
          .createBitmap(
              getWidth(),
              getHeight(),
              drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                  : Bitmap.Config.RGB_565);
      Canvas canvas1 = new Canvas(bitmap);
      // canvas.setBitmap(bitmap);
      drawable.setBounds(0, 0, getWidth(),
          getHeight());
      drawable.draw(canvas1);
    }
    else {
      super.onDraw(canvas);
    }
  }
 
  /**
   * 获取圆角矩形图片方法
   * @param bitmap
   * @param roundPx,一般设置成14
   * @return Bitmap
   * @author caizhiming
   */
  private Bitmap getRoundBitmap(Bitmap bitmap, int roundPx) {
    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());
    final RectF rectF = new RectF(rect);
    paint.setAntiAlias(true);
    canvas.drawARGB(0, 0, 0, 0);
    paint.setColor(color);
    int x = bitmap.getWidth();
 
    canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
    paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
    canvas.drawBitmap(bitmap, rect, rect, paint);
    return output;
 
 
  }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/swipelayout"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content" >
 
    <com.yizooo.yizooo.ui.RoundImageView
      android:id="@+id/item_frag_news_icon"
      android:layout_width="@dimen/dp_47"
      android:layout_height="@dimen/dp_50"
      android:scaleType="fitXY"
      android:src="@mipmap/fuwutongzhi"
      android:layout_margin="@dimen/dp_10"
      />
</RelativeLayout>