阴影+边界+角半径

    scrollview.backgroundColor = [UIColor whiteColor]; 
    CALayer *ScrlViewLayer = [scrollview layer];
    [ScrlViewLayer setMasksToBounds:NO ];
    [ScrlViewLayer setShadowColor:[[UIColor lightGrayColor] CGColor]];
    [ScrlViewLayer setShadowOpacity:1.0 ];
    [ScrlViewLayer setShadowRadius:6.0 ];
    [ScrlViewLayer setShadowOffset:CGSizeMake( 0 , 0 )];
    [ScrlViewLayer setShouldRasterize:YES];
    [ScrlViewLayer setCornerRadius:5.0];
    [ScrlViewLayer setBorderColor:[UIColor lightGrayColor].CGColor];
    [ScrlViewLayer setBorderWidth:1.0];
    [ScrlViewLayer setShadowPath:[UIBezierPath bezierPathWithRect:scrollview.bounds].CGPath];

如果你特别想为uibutton定制圆角，有很多不同的方法来实现。

下面的代码示例(感谢Erica)很好地概述了所有可能性。

iOS 15之前的圆角按钮

在iOS 15之前，你可以通过设置图层来制作圆角按钮。cornerRadius, backgroundColor和setTitleColor。

let button = UIButton(type: .system)
button.setTitle("Button", for: .normal)
button.setTitleColor(.white, for: .normal)
button.backgroundColor = .systemPink
button.layer.cornerRadius = 8

button.contentEdgeInsets = UIEdgeInsets(
  top: 10,
  left: 20,
  bottom: 10,
  right: 20
)

胶囊按钮

如果我们增加足够大的角半径值，您可以创建一个胶囊风格的按钮。为了创建一个胶囊风格的按钮，我们设置角半径等于按钮高度的一半。由于按钮的高度可能会根据标题大小或布局而变化，我通常为胶囊样式创建一个UIButton子类。

class CapsuleButton: UIButton {
  override func layoutSubviews() {
    super.layoutSubviews()
    let height = bounds.height
    layer.cornerRadius = height/2
  }
}

let capsule = CapsuleButton(type: .system)
capsule.setTitle("Button", for: .normal)
capsule.setTitleColor(.white, for: .normal)
capsule.backgroundColor = .systemPink
capsule.contentEdgeInsets = UIEdgeInsets(
  top: 10,
  left: 20,
  bottom: 10,
  right: 20
)

光滑的角落

如果你想复制苹果平滑角，你也可以用拐角曲线属性来做。要创建连续的平滑角，请设置图层。按钮连续的曲线。

let button = UIButton(type: .system)
button.setTitle("Button", for: .normal)
button.setTitleColor(.white, for: .normal)
button.backgroundColor = .systemPink
button.layer.cornerRadius = 8
button.layer.cornerCurve = .continuous

button.contentEdgeInsets = UIEdgeInsets(
  top: 10,
  left: 20,
  bottom: 10,
  right: 20
)

圆角按钮在iOS 15使用UIButton。配置

在iOS 15中，苹果引入了一种通过UIButton.Configuration自定义按钮的新方法。

var configuration = UIButton.Configuration.filled()

configuration.title = "Button"
configuration.baseBackgroundColor = UIColor.systemPink
configuration.contentInsets = NSDirectionalEdgeInsets(
  top: 10,
  leading: 20,
  bottom: 10,
  trailing: 20
)

let button = UIButton(configuration: configuration, primaryAction: nil)

使用cornerStyle控制角的半径

UIButton。配置有许多内置的角样式供您选择。你可以用cornerStyle属性来设置。

configuration.cornerStyle = .small
configuration.cornerStyle = .medium
configuration.cornerStyle = .large
configuration.cornerStyle = .capsule

自定义角半径

如果你想要一些更独特的东西，你可以通过UIBackgroundConfiguration的cornerRadius指定角的半径。

var configuration = UIButton.Configuration.filled()
configuration.title = "Button"
configuration.baseBackgroundColor = UIColor.systemPink
configuration.contentInsets = NSDirectionalEdgeInsets(
  top: 10,
  leading: 20,
  bottom: 10,
  trailing: 20
)
configuration.background.cornerRadius = 20

configuration.cornerStyle = .fixed


let button = UIButton(configuration: configuration, primaryAction: nil)

extension UIView {
    func dropRoundedShadowForAllSides() {
        let backgroundView = UIView(frame:self.frame)
        let radius = frame.height/2
        backgroundView.layer.masksToBounds = false
        self.layer.masksToBounds = true
        backgroundView.layer.shadowOffset = CGSize(width: 0.0, height: 0.0)
        backgroundView.layer.shadowRadius = 4
        backgroundView.layer.shadowOpacity = 0.4

        let path = UIBezierPath()

        // Start at the Top Left Corner + radius distance
        path.move(to: CGPoint(x: 2*radius, y: 0.0))

        // Move to the Top Right Corner - radius distance
        path.addLine(to: CGPoint(x: backgroundView.frame.size.width - radius, y: 0.0))

        // Move to top right corner + radius down as curve
        let centerPoint1 = CGPoint(x:backgroundView.frame.size.width - radius,y:radius)
        path.addArc(withCenter: centerPoint1, radius: radius, startAngle: 3*(.pi/2), endAngle: 0, clockwise: true)

        // Move to the Bottom Right Corner - radius
        path.addLine(to: CGPoint(x: backgroundView.frame.size.width, y: backgroundView.frame.size.height - radius))

        // Move to top right corner + radius left as curve
        let centerPoint2 = CGPoint(x:backgroundView.frame.size.width - radius,y:backgroundView.frame.size.height - radius)
        path.addArc(withCenter: centerPoint2, radius: radius, startAngle: 0, endAngle: .pi/2, clockwise: true)

        // Move to the Bottom Left Corner - radius
        path.addLine(to: CGPoint(x: radius, y: backgroundView.frame.size.height))

        // Move to left right corner - radius up as curve
        let centerPoint3 = CGPoint(x:radius,y:backgroundView.frame.size.height - radius)
        path.addArc(withCenter: centerPoint3, radius: radius, startAngle: .pi/2, endAngle: .pi, clockwise: true)

        // Move to the top Left Corner - radius
        path.addLine(to: CGPoint(x: 0, y: radius))

        // Move to top right corner + radius down as curve
        let centerPoint4 = CGPoint(x:radius,y:radius)
        path.addArc(withCenter: centerPoint4, radius: radius, startAngle: .pi, endAngle: 3 * (.pi/2), clockwise: true)

        path.close()

        backgroundView.layer.shadowPath = path.cgPath
        if let superView = self.superview {
            superView.addSubview(backgroundView)
            superView.sendSubview(toBack: backgroundView)
            superView.bringSubview(toFront: self)
        }

    }
}

这里有一个肯定有效的解决方案!

我已经创建了UIView扩展所需的边应用阴影如下

enum AIEdge:Int {
    case
    Top,
    Left,
    Bottom,
    Right,
    Top_Left,
    Top_Right,
    Bottom_Left,
    Bottom_Right,
    All,
    None
}

extension UIView {
        
    func applyShadowWithCornerRadius(color:UIColor, opacity:Float, radius: CGFloat, edge:AIEdge, shadowSpace:CGFloat, cornerRadius: CGFloat)    {

        var sizeOffset:CGSize = CGSize.zero
        
        switch edge {
        case .Top:
            sizeOffset = CGSize(width: 0, height: -shadowSpace)
        case .Left:
            sizeOffset = CGSize(width: -shadowSpace, height: 0)
        case .Bottom:
            sizeOffset = CGSize(width: 0, height: shadowSpace)
        case .Right:
            sizeOffset = CGSize(width: shadowSpace, height: 0)
            
            
        case .Top_Left:
            sizeOffset = CGSize(width: -shadowSpace, height: -shadowSpace)
        case .Top_Right:
            sizeOffset = CGSize(width: shadowSpace, height: -shadowSpace)
        case .Bottom_Left:
            sizeOffset = CGSize(width: -shadowSpace, height: shadowSpace)
        case .Bottom_Right:
            sizeOffset = CGSize(width: shadowSpace, height: shadowSpace)
            
            
        case .All:
            sizeOffset = CGSize(width: 0, height: 0)
        case .None:
            sizeOffset = CGSize.zero
        }

        self.layer.cornerRadius = cornerRadius
        self.layer.masksToBounds = true

        self.layer.shadowColor = color.cgColor
        self.layer.shadowOpacity = opacity
        self.layer.shadowOffset = sizeOffset
        self.layer.shadowRadius = radius
        self.layer.masksToBounds = false

        self.layer.shadowPath = UIBezierPath(roundedRect:self.bounds, cornerRadius:self.layer.cornerRadius).cgPath
    }
}

最后，你可以为你的UIView子类调用下面的阴影函数，你也可以指定边缘上应用阴影，尝试不同的变化根据你需要改变下面方法调用的参数。

viewRoundedToBeShadowedAsWell.applyShadowWithCornerRadius(color: .gray, opacity: 1, radius: 15, edge: AIEdge.All, shadowSpace: 15)

注意:如果仍然不工作，试着从主线程调用它

DispatchQueue.main.async {
   viewRoundedToBeShadowedAsWell.applyShadowWithCornerRadius(color: .gray, opacity: 1, radius: 15, edge: AIEdge.All, shadowSpace: 15)
}

希望有人觉得这有用!

以下是结果图片:

检查GitHub上的示例项目，以确保正确使用组件。

简单的Swift 5解决方案，没有任何额外的子视图或子类化:

extension UIView {

    func addShadow(offset: CGSize, color: UIColor, radius: CGFloat, opacity: Float) {
        layer.masksToBounds = false
        layer.shadowOffset = offset
        layer.shadowColor = color.cgColor
        layer.shadowRadius = radius
        layer.shadowOpacity = opacity

        let backgroundCGColor = backgroundColor?.cgColor
        backgroundColor = nil
        layer.backgroundColor =  backgroundCGColor
    }
}

请注意，在调用addShadow之前，您应该使用角半径和其他属性设置视图。

之后，像这样从viewDidLoad调用这个:

button.addShadow(offset: CGSize.init(width: 0, height: 3), color: UIColor.black, radius: 2.0, opacity: 0.35)

最终结果:

超级简单!

这就是你怎么做的，有圆角和圆角阴影，而不用担心路径。

//Inner view with content
[imageView.layer setBorderColor:[[UIColor lightGrayColor] CGColor]];
[imageView.layer setBorderWidth:1.0f];
[imageView.layer setCornerRadius:8.0f];
[imageView.layer setMasksToBounds:YES];

//Outer view with shadow
UIView* shadowContainer = [[UIView alloc] initWithFrame:imageView.frame];
[shadowContainer.layer setMasksToBounds:NO];
[shadowContainer.layer setShadowColor:[[UIColor blackColor] CGColor]];
[shadowContainer.layer setShadowOpacity:0.6f];
[shadowContainer.layer setShadowRadius:2.0f];
[shadowContainer.layer setShadowOffset: CGSizeMake(0.0f, 2.0f)];

[shadowContainer addSubview:imageView];

带有内容的视图，在我的例子中是UIImageView，有一个角半径，因此必须屏蔽到边界。

我们为阴影创建另一个同样大小的视图，设置它的maskToBounds为NO，然后将内容视图添加到容器视图(例如shadowContainer)。