最近有一个实现一个带有圆角的ImageView的需求，在网上找了找三方，虽然Demo都是正确的，但是移植过来就不可以了，因为请求链接的时候用的是xUtils中Bitmap来进行解析的，这样就总是会报类型转换异常的错误。

就这样只能自己定义一个了.

Demo:

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,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,b.getWidth(),b.getHeight());
      final Rect rectDest = new Rect(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,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,bitmap.getWidth(),bitmap.getHeight());
    final RectF rectF = new RectF(rect);
    paint.setAntiAlias(true);
    canvas.drawARGB(0,0);
    paint.setColor(color);
    int x = bitmap.getWidth();

    canvas.drawRoundRect(rectF,roundPx,paint);
    paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
    canvas.drawBitmap(bitmap,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>

最终的效果图就不发照片了,各位朋友尝试一下就可以看出效果图了。

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