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

在swift 4.3中,修改代码后@apinho工作正常

extension UIView {
func roundCornersWithLayerMask(cornerRadii: CGFloat, corners: UIRectCorner) {
    let path = UIBezierPath(roundedRect: bounds,
                            byRoundingCorners: corners,
                            cornerRadii: CGSize(width: cornerRadii, height: cornerRadii))
    let maskLayer = CAShapeLayer()
    maskLayer.path = path.cgPath
    layer.mask = maskLayer
  }
}

为您的视图使用此函数

YourViewName. roundCornersWithLayerMask(cornerRadii: 20,corners: [.topLeft,.topRight])

其他回答

    // 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;

Emma: . topright和。bottom right对你不起作用,可能是因为视图调用。roundCorners是在最终视图边界计算之前完成的。注意,贝塞尔路径在被调用时起源于视图边界。例如,如果自动布局将缩小视图,右侧的圆角可能在视图之外。 尝试在viewDidLayoutSubviews中调用它,其中视图的边界是final。

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
}()

以下是Swift 5的最佳方法:

import UIKit

extension UIView {

func roundCorners(radius: CGFloat = 10, corners: UIRectCorner = .allCorners) {
        self.clipsToBounds = true
        self.layer.cornerRadius = radius
        if #available(iOS 11.0, *) {
            var arr: CACornerMask = []
            
            let allCorners: [UIRectCorner] = [.topLeft, .topRight, .bottomLeft, .bottomRight, .allCorners]
            
            for corn in allCorners {
                if(corners.contains(corn)){
                    switch corn {
                    case .topLeft:
                        arr.insert(.layerMinXMinYCorner)
                    case .topRight:
                        arr.insert(.layerMaxXMinYCorner)
                    case .bottomLeft:
                        arr.insert(.layerMinXMaxYCorner)
                    case .bottomRight:
                        arr.insert(.layerMaxXMaxYCorner)
                    case .allCorners:
                        arr.insert(.layerMinXMinYCorner)
                        arr.insert(.layerMaxXMinYCorner)
                        arr.insert(.layerMinXMaxYCorner)
                        arr.insert(.layerMaxXMaxYCorner)
                    default: break
                    }
                }
            }
            self.layer.maskedCorners = arr
        } else {
            self.roundCornersBezierPath(corners: corners, radius: radius)
        }
    }
    
    private func roundCornersBezierPath(corners: UIRectCorner, radius: CGFloat) {
        let path = UIBezierPath(roundedRect: bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
        let mask = CAShapeLayer()
        mask.path = path.cgPath
        layer.mask = mask
    }
    
}

最简单的方法是用圆角层做一个蒙版。

CALayer *maskLayer = [CALayer layer];
maskLayer.frame = CGRectMake(0,0,maskWidth ,maskHeight);
maskLayer.contents = (__bridge id)[[UIImage imageNamed:@"maskImageWithRoundedCorners.png"] CGImage];

aUIView.layer.mask = maskLayer;

别忘了:

#import <QuartzCore/QuartzCore.h>