public class TipNumberView extends TextView {

  private Paint mBgPaint ;
  PaintFlagsDrawFilter pfd; 
  public TipNumberView(Context context, AttributeSet attrs) {
    super(context, attrs);
    //初始化畫筆
    mBgPaint = new Paint();
    mBgPaint.setColor(Color.RED);
    mBgPaint.setAntiAlias(true);

    pfd = new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG); 
  }
  public TipNumberView(Context context) {
    this(context,null);

  }
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    //得到測量的高度和寬度
    int measuredWidth = getMeasuredWidth();
    int measuredHeight = getMeasuredHeight();
    int max = Math.max(measuredWidth, measuredHeight);
    //設(shè)置控件區(qū)域大小
    setMeasuredDimension(max, max);
  }

  //設(shè)置背景顏色
  @Override
  public void setBackgroundColor(int color){
    mBgPaint.setColor(color);
  }

  /**
   * 設(shè)置通知個數(shù)顯示
   * @param text
   */
  public void setNotifiText(int text){
    setText(text+"");
  }

  public void setNotifiText(String text){
    setText(text);
  }

  //繪圖
  @Override
  public void draw(Canvas canvas) {
    //設(shè)置繪圖無鋸齒
    canvas.setDrawFilter(pfd);
    canvas.drawCircle(getWidth()/2, getHeight()/2, Math.max(getWidth()/2, getHeight())/2, mBgPaint);
    super.draw(canvas);
  }
}