下面用 Path 画一个菱形

		
      Paint milestonesPaint = new Paint();
      milestonesPaint.setStyle(Paint.Style.FILL);
      milestonesPaint.setColor(Color.BLACK);

      Path path = new Path();
      path.moveTo(startCoordinates.x + calendarFontSpacing / 2, startY);
      path.lineTo(startCoordinates.x + calendarFontSpacing, stopY - calendarFontSpacing / 2);
      path.lineTo(startCoordinates.x + calendarFontSpacing / 2, stopY);
      path.lineTo(startCoordinates.x, stopY - calendarFontSpacing / 2);
      path.close();//封闭
      canvas.drawPath(path, milestonesPaint);