类似QQ在线离线好友界面

把头像设置成圆形的代码如下：

 package com.example.lesson6_11_id19;

 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffXfermode;
 import android.graphics.RectF;
 import android.graphics.Xfermode;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.NinePatchDrawable;
 import android.util.AttributeSet;
 import android.widget.ImageView;

 public class CircleImageView extends ImageView {
     private static final Xfermode MASK_XFERMODE;
     private Bitmap mask;
     private Paint paint;
     private int mBorderWidth = 10;
     private int mBorderColor = Color.parseColor("#f2f2f2");
     private boolean useDefaultStyle = false;

     static {
         PorterDuff.Mode localMode = PorterDuff.Mode.DST_IN;
         MASK_XFERMODE = new PorterDuffXfermode(localMode);
     }

     public CircleImageView(Context context) {
         super(context);
     }

     public CircleImageView(Context context, AttributeSet attrs) {
         this(context, attrs, 0);
     }

     public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
         TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CircularImage);
         mBorderColor = a.getColor(R.styleable.CircularImage_border_color, mBorderColor);
         final int def = (int) (2*context.getResources().getDisplayMetrics().density + 0.5f);
         mBorderWidth = a.getDimensionPixelOffset(R.styleable.CircularImage_border_width, def);
         a.recycle();
     }

     private void useDefaultStyle(boolean useDefaultStyle) {
         this.useDefaultStyle = useDefaultStyle;
     }

     @Override
     protected void onDraw(Canvas canvas) {
         if(useDefaultStyle) {
             super.onDraw(canvas);
             return ;
         }
         final Drawable localDraw = getDrawable();
         if(localDraw == null) {
             return ;
         }
         if(localDraw instanceof NinePatchDrawable) {
             return ;
         }
         if (this.paint == null) {
             final Paint localPaint = new Paint();
             localPaint.setFilterBitmap(false);
             localPaint.setAntiAlias(true);
             localPaint.setXfermode(MASK_XFERMODE);
             this.paint = localPaint;
         }
         final int width = getWidth();
         final int height = getHeight();
         /** ����layer */
         int layer = canvas.saveLayer(0.0F, 0.0F, width, height, null, 31);
         /** ����drawable�Ĵ�С */
         localDraw.setBounds(0, 0, width, height);
         /** ��drawable�