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

只查看toppleft和TopRight角半径

lazy var footerBackgroundView: UIView = {

    let view = UIView()
    view.translatesAutoresizingMaskIntoConstraints = false
    view.backgroundColor = .blue

    //Make Corners Radius TopLeft & Top Right
    view.clipsToBounds = true
    view.layer.cornerRadius = 8
    view.layer.maskedCorners = [.layerMaxXMinYCorner, .layerMinXMinYCorner] 
    
    return view
}()

其他回答

只查看toppleft和TopRight角半径

lazy var footerBackgroundView: UIView = {

    let view = UIView()
    view.translatesAutoresizingMaskIntoConstraints = false
    view.backgroundColor = .blue

    //Make Corners Radius TopLeft & Top Right
    view.clipsToBounds = true
    view.layer.cornerRadius = 8
    view.layer.maskedCorners = [.layerMaxXMinYCorner, .layerMinXMinYCorner] 
    
    return view
}()
    // Create the path (with only the top-left corner rounded)
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds 
                           byRoundingCorners:(UIRectCornerBottomLeft | UIRectCornerBottomRight) 
                           cornerRadii:CGSizeMake(7.0, 7.0)];

// Create the shape layer and set its path
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = cell.stripBlackImnageView.bounds;
maskLayer.path = maskPath.CGPath; 
// Set the newly created shapelayer as the mask for the image view's layer
view.layer.mask = maskLayer;

我不知道为什么你的解决方案没有工作,但下面的代码是为我工作。创建一个贝塞尔蒙版,并将其应用到您的视图。在下面的代码中,我将_backgroundView的底角圆角化为3个像素。self是一个自定义的UITableViewCell:

UIBezierPath *maskPath = [UIBezierPath
    bezierPathWithRoundedRect:self.backgroundImageView.bounds
    byRoundingCorners:(UIRectCornerBottomLeft | UIRectCornerBottomRight)
    cornerRadii:CGSizeMake(20, 20)
];

CAShapeLayer *maskLayer = [CAShapeLayer layer];

maskLayer.frame = self.bounds;
maskLayer.path = maskPath.CGPath;

self.backgroundImageView.layer.mask = maskLayer;

Swift 2.0版本与一些改进:

let path = UIBezierPath(roundedRect:viewToRound.bounds, byRoundingCorners:[.TopRight, .BottomLeft], cornerRadii: CGSizeMake(20, 20))
let maskLayer = CAShapeLayer()

maskLayer.path = path.CGPath
viewToRound.layer.mask = maskLayer

Swift 3.0版本:

let path = UIBezierPath(roundedRect:viewToRound.bounds,
                        byRoundingCorners:[.topRight, .bottomLeft],
                        cornerRadii: CGSize(width: 20, height:  20))

let maskLayer = CAShapeLayer()

maskLayer.path = path.cgPath
viewToRound.layer.mask = maskLayer

这里的快速扩展

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;

如果你正在寻找一个界面构建器的唯一解决方案,有一个适用于iOS 11或更高版本。在这里可以看到我的答案:https://stackoverflow.com/a/58626264