iOS 給View 設定指定位置圓角

`

• (instancetype)initWithFrame:(CGRect)frame

  {

  if (self = [super initWithFrame:frame]) {

  UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerTopRight cornerRadii:CGSizeMake(20, 20)];
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = self.bounds;
    maskLayer.path = maskPath.CGPath;
    self.layer.mask = maskLayer;
    
    [self createUI];
             

  }

  return self;

}

`