///设置圆角[左上、右上角]
- (void)setCircular{
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerTopRight cornerRadii:CGSizeMake(20,20)];
    //创建 layer
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = self.bounds;
    //赋值
    maskLayer.path = maskPath.CGPath;
    self.layer.mask = maskLayer;
}