Android 给应用程序的icon添加未读消息个数提示（红圈内数字）

/** 
  * 绘制图标右上角的未读消息数量显示 
  * 
  * @param context 
  *   上下文 
  * @param icon 
  *   需要被添加的icon的资源ID 
  * @param news 
  *   未读的消息数量 
  * @return drawable 
  */ 
 @SuppressWarnings("unused") 
 public static Drawable displayNewsNumber(Context context, int icon, int news) { 
  // 初始化画布 
  int iconSize = (int) context.getResources().getDimension( 
    android.R.dimen.app_icon_size); 
  // Bitmap contactIcon = Bitmap.createBitmap(iconSize, iconSize, 
  // Config.ARGB_8888); 
  Bitmap iconBitmap = BitmapFactory.decodeResource( 
    context.getResources(), icon); 
  Canvas canvas = new Canvas(iconBitmap); 
  // 拷贝图片 
  Paint iconPaint = new Paint(); 
  iconPaint.setDither(true);// 防抖动 
  iconPaint.setFilterBitmap(true);// 用来对Bitmap进行滤波处理 
  Rect src = new Rect(0, 0, iconBitmap.getWidth(), iconBitmap.getHeight()); 
  Rect dst = new Rect(0, 0, iconBitmap.getWidth(), iconBitmap.getHeight()); 
  canvas.drawBitmap(iconBitmap, src, dst, iconPaint); 
  // 启用抗锯齿和使用设备的文本字距 
  Paint countPaint = new Paint(Paint.ANTI_ALIAS_FLAG 
    | Paint.DEV_KERN_TEXT_FLAG); 
  countPaint.setColor(Color.RED); 
  canvas.drawCircle(iconSize - 13, 20, 10, countPaint); 

  Paint textPaint = new Paint(); 
  textPaint.setColor(Color.WHITE); 
  // textPaint.setTypeface(Typeface.DEFAULT_BOLD); 
  textPaint.setTextSize(19f); 
  canvas.drawText(String.valueOf(news), iconSize - 18, 27, textPaint); 
  return new BitmapDrawable(iconBitmap); 
 } 

if (count > 0) {//显示右上角未读消息提示 
   Drawable mineDrawable = BitmapUtil.displayNewsNumber(this, 
     R.drawable.icon_mine, count); 
   mineButton.setCompoundDrawablesWithIntrinsicBounds(null, null, 
     null, mineDrawable);//这里就是设置背景，自行发挥。 
  } else {//隐藏 
   Drawable defaultDrawable = getResources().getDrawable( 
     R.drawable.icon_mine); 
   mineButton.setCompoundDrawablesWithIntrinsicBounds(null, null, 
     null, defaultDrawable); 
  }