有没有办法为一个UIView的左上角和右上角设置角半径?

我尝试了下面的方法,但最终它再也看不到视图了。

UIView *view = [[UIView alloc] initWithFrame:frame];

CALayer *layer = [CALayer layer];
UIBezierPath *shadowPath = [UIBezierPath bezierPathWithRoundedRect:frame byRoundingCorners:(UIRectCornerTopLeft|UIRectCornerTopRight) cornerRadii:CGSizeMake(3.0, 3.0)];
layer.shadowPath = shadowPath.CGPath;
view.layer.mask = layer;

当前回答

这是如何在c#中使用Xamarin为按钮的每个角落设置角半径:

var maskPath = UIBezierPath.FromRoundedRect(MyButton.Bounds, UIRectCorner.BottomLeft | UIRectCorner.BottomRight,
    new CGSize(10.0, 10.0));
var maskLayer = new CAShapeLayer
{
    Frame = MyButton.Bounds,
    Path = maskPath.CGPath
};
MyButton.Layer.Mask = maskLayer;

其他回答

最后,在iOS11中有CACornerMask ! 使用CACornerMask可以很容易地完成:

let view = UIView()
view.clipsToBounds = true
view.layer.cornerRadius = 10
view.layer.maskedCorners = [.layerMaxXMinYCorner, .layerMinXMinYCorner] // Top right corner, Top left corner respectively

下面是@JohnnyRockex的Swift版本的回答

extension UIView {

    func roundCorners(_ corners: UIRectCorner, radius: CGFloat) {
         let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
         let mask = CAShapeLayer()
         mask.path = path.cgPath
         self.layer.mask = mask
    }

}

view.roundCorners([.topLeft, .bottomRight], radius: 10)

Note

如果你正在使用自动布局,你需要子类化你的UIView,并在视图的layoutSubviews中调用roundCorners以获得最佳效果。

class View: UIView {
    override func layoutSubviews() {
        super.layoutSubviews()

        self.roundCorners([.topLeft, .bottomLeft], radius: 10)
    }
}

一种编程的方法是创建一个UIView在UIView顶部有圆角的部分。或者你可以把顶部藏在什么东西下面。

这是如何在c#中使用Xamarin为按钮的每个角落设置角半径:

var maskPath = UIBezierPath.FromRoundedRect(MyButton.Bounds, UIRectCorner.BottomLeft | UIRectCorner.BottomRight,
    new CGSize(10.0, 10.0));
var maskLayer = new CAShapeLayer
{
    Frame = MyButton.Bounds,
    Path = maskPath.CGPath
};
MyButton.Layer.Mask = maskLayer;

在Swift 4.2中,通过@IBDesignable创建它,如下所示:

@IBDesignable

class DesignableViewCustomCorner: UIView {

    @IBInspectable var cornerRadious: CGFloat = 0 {
        didSet {
            let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: [.topLeft, .topRight], cornerRadii: CGSize(width: cornerRadious, height: cornerRadious))
            let mask = CAShapeLayer()
            mask.path = path.cgPath
            self.layer.mask = mask
        }
    }

}