Swift - Problems with corner radius and drop shado

问题:

I'm trying to create a button with rounded corners and a drop shadow. No matter how I switch up, the button will not display correctly. I've tried masksToBounds = false and masksToBounds = true, but either the corner radius works and the shadow does not or the shadow works and the corner radius doesn't clip the corners of the button.

import UIKit
import QuartzCore

@IBDesignable
class Button : UIButton
{
    @IBInspectable var masksToBounds: Bool    = false                {didSet{updateLayerProperties()}}
    @IBInspectable var cornerRadius : CGFloat = 0                    {didSet{updateLayerProperties()}}
    @IBInspectable var borderWidth  : CGFloat = 0                    {didSet{updateLayerProperties()}}
    @IBInspectable var borderColor  : UIColor = UIColor.clearColor() {didSet{updateLayerProperties()}}
    @IBInspectable var shadowColor  : UIColor = UIColor.clearColor() {didSet{updateLayerProperties()}}
    @IBInspectable var shadowOpacity: CGFloat = 0                    {didSet{updateLayerProperties()}}
    @IBInspectable var shadowRadius : CGFloat = 0                    {didSet{updateLayerProperties()}}
    @IBInspectable var shadowOffset : CGSize  = CGSizeMake(0, 0)     {didSet{updateLayerProperties()}}

    override func drawRect(rect: CGRect)
    {
        updateLayerProperties()
    }

    func updateLayerProperties()
    {
        self.layer.masksToBounds = masksToBounds
        self.layer.cornerRadius = cornerRadius
        self.layer.borderWidth = borderWidth
        self.layer.borderColor = borderColor.CGColor
        self.layer.shadowColor = shadowColor.CGColor
        self.layer.shadowOpacity = CFloat(shadowOpacity)
        self.layer.shadowRadius = shadowRadius
        self.layer.shadowOffset = shadowOffset
    }
}

回答1:

The following Swift 3 code shows how to set a subclass of UIButton that allows to create instances with rounded corners and shadow around it:

import UIKit

class CustomButton: UIButton {

    var shadowLayer: CAShapeLayer!

    override func layoutSubviews() {
        super.layoutSubviews()

        if shadowLayer == nil {
            shadowLayer = CAShapeLayer()
            shadowLayer.path = UIBezierPath(roundedRect: bounds, cornerRadius: 12).cgPath
            shadowLayer.fillColor = UIColor.white.cgColor

            shadowLayer.shadowColor = UIColor.darkGray.cgColor
            shadowLayer.shadowPath = shadowLayer.path
            shadowLayer.shadowOffset = CGSize(width: 2.0, height: 2.0)
            shadowLayer.shadowOpacity = 0.8
            shadowLayer.shadowRadius = 2

            layer.insertSublayer(shadowLayer, at: 0)
            //layer.insertSublayer(shadowLayer, below: nil) // also works
        }        
    }

}

---

According to your needs, you may add a UIButton in your Storyboard and set its class to CustomButton or you may create an instance of CustomButton programmatically. The following UIViewController implementation shows how to create and use a CustomButton instance programmatically:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let button = CustomButton(type: .system)
        button.setTitle("Button", for: .normal)
        view.addSubview(button)

        // Auto layout code using anchors (iOS9+)
        // set witdh and height constraints if necessary
        button.translatesAutoresizingMaskIntoConstraints = false
        let horizontalConstraint = button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        let verticalConstraint = button.centerYAnchor.constraint(equalTo: view.centerYAnchor)        
        let widthConstraint = button.widthAnchor.constraint(equalToConstant: 100)
        let heightConstraint = button.heightAnchor.constraint(equalToConstant: 100)
        NSLayoutConstraint.activate([horizontalConstraint, verticalConstraint, widthConstraint, heightConstraint])
    }

}

---

The previous code produces the image below in the iPhone simulator:

回答2:

To expand on Imanou's post, it's possible to programmatically add the shadow layer in the custom button class

@IBDesignable class CustomButton: UIButton {
    var shadowAdded: Bool = false

    @IBInspectable var cornerRadius: CGFloat = 0 {
        didSet {
            layer.cornerRadius = cornerRadius
            layer.masksToBounds = cornerRadius > 0
        }
    }

    override func drawRect(rect: CGRect) {
        super.drawRect(rect)

        if shadowAdded { return }
        shadowAdded = true

        let shadowLayer = UIView(frame: self.frame)
        shadowLayer.backgroundColor = UIColor.clearColor()
        shadowLayer.layer.shadowColor = UIColor.darkGrayColor().CGColor
        shadowLayer.layer.shadowPath = UIBezierPath(roundedRect: bounds, cornerRadius: self.cornerRadius).CGPath
        shadowLayer.layer.shadowOffset = CGSize(width: 1.0, height: 1.0)
        shadowLayer.layer.shadowOpacity = 0.5
        shadowLayer.layer.shadowRadius = 1
        shadowLayer.layer.masksToBounds = true
        shadowLayer.clipsToBounds = false

        self.superview?.addSubview(shadowLayer)
        self.superview?.bringSubviewToFront(self)
    }
}

回答3:

An alternative way to get more usable and consistent button.

Swift 2

func getImageWithColor(color: UIColor, size: CGSize, cornerRadius:CGFloat) -> UIImage {
    let rect = CGRectMake(0, 0, size.width, size.height)
    UIGraphicsBeginImageContextWithOptions(size, false, 1)
    UIBezierPath(
        roundedRect: rect,
        cornerRadius: cornerRadius
        ).addClip()
    color.setFill()
    UIRectFill(rect)
    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
}

let button = UIButton(type: .Custom)
button.frame = CGRectMake(20, 20, 200, 50)
button.setTitle("My Button", forState: UIControlState.Normal)
button.setTitleColor(UIColor.blackColor(), forState: UIControlState.Normal)
self.addSubview(button)

let image = getImageWithColor(UIColor.whiteColor(), size: button.frame.size, cornerRadius: 5)
button.setBackgroundImage(image, forState: UIControlState.Normal)

button.layer.shadowRadius = 5
button.layer.shadowColor = UIColor.blackColor().CGColor
button.layer.shadowOpacity = 0.5
button.layer.shadowOffset = CGSizeMake(0, 1)
button.layer.masksToBounds = false

Swift 3

func getImageWithColor(_ color: UIColor, size: CGSize, cornerRadius:CGFloat) -> UIImage? {
    let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
    UIGraphicsBeginImageContextWithOptions(size, false, 0)
    color.setFill()
    UIBezierPath(roundedRect: rect, cornerRadius: cornerRadius).addClip()
    color.setFill()
    UIRectFill(rect)
    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    return image
}

let button = UIButton(type: .custom)
button.frame = CGRect(x:20, y:20, width:200, height:50)
button.setTitle("My Button", for: .normal)
button.setTitleColor(UIColor.black, for: .normal)
self.addSubview(button)

if let image = getImageWithColor(UIColor.white, size: button.frame.size, cornerRadius: 5) {
    button.setBackgroundImage(image, for: .normal)
}

button.layer.shadowRadius = 5
button.layer.shadowColor = UIColor.black.cgColor
button.layer.shadowOpacity = 0.5
button.layer.shadowOffset = CGSize(width:0, height:1)
button.layer.masksToBounds = false

回答4:

My custom button with some shadow and rounded corners, I use it directly within the Storyboard with no need to touch it programmatically.

Swift 4

class RoundedButtonWithShadow: UIButton {
    override func awakeFromNib() {
        super.awakeFromNib()
        self.layer.masksToBounds = false
        self.layer.cornerRadius = self.frame.height/2
        self.layer.shadowColor = UIColor.black.cgColor
        self.layer.shadowPath = UIBezierPath(roundedRect: self.bounds, cornerRadius: self.layer.cornerRadius).cgPath
        self.layer.shadowOffset = CGSize(width: 0.0, height: 3.0)
        self.layer.shadowOpacity = 0.5
        self.layer.shadowRadius = 1.0
    }
}

回答5:

To improve PiterPan's answer and show a real shadow (not just a background with no blur) with a circular button in Swift 3:

override func viewDidLoad() {
    super.viewDidLoad()
    myButton.layer.masksToBounds = false
    myButton.layer.cornerRadius = myButton.frame.height/2
    myButton.clipsToBounds = true
}

override func viewDidLayoutSubviews() {
    addShadowForRoundedButton(view: self.view, button: myButton, opacity: 0.5)
}

func addShadowForRoundedButton(view: UIView, button: UIButton, opacity: Float = 1) {
    let shadowView = UIView()
    shadowView.backgroundColor = UIColor.black
    shadowView.layer.opacity = opacity
    shadowView.layer.shadowRadius = 5
    shadowView.layer.shadowOpacity = 0.35
    shadowView.layer.shadowOffset = CGSize(width: 0, height: 0)
    shadowView.layer.cornerRadius = button.bounds.size.width / 2
    shadowView.frame = CGRect(origin: CGPoint(x: button.frame.origin.x, y: button.frame.origin.y), size: CGSize(width: button.bounds.width, height: button.bounds.height))
    self.view.addSubview(shadowView)
    view.bringSubview(toFront: button)
}

回答6:

If somebody need add shadows to rounded buttons in Swift 3.0, here is a good method to do it.

func addShadowForRoundedButton(view: UIView, button: UIButton, shadowColor: UIColor, shadowOffset: CGSize, opacity: Float = 1) {
    let shadowView = UIView()
    shadowView.backgroundColor = shadowColor
    shadowView.layer.opacity = opacity
    shadowView.layer.cornerRadius = button.bounds.size.width / 2
    shadowView.frame = CGRect(origin: CGPoint(x: button.frame.origin.x + shadowOffset.width, y: button.frame.origin.y + shadowOffset.height), size: CGSize(width: button.bouds.width, height: button.bounds.height))
    self.view.addSubview(shadowView)
    view.bringSubview(toFront: button)
}

Use this method in func viewDidLayoutSubviews() as bellow:

override func viewDidLayoutSubviews() {
    addShadowForRoundedButton(view: self.view, button: button, shadowColor: .black, shadowOffset: CGSize(width: 2, height: 2), opacity: 0.5)
}

The effect of this method is:

回答7:

Refactored this to support any view. Subclass your view from this and it should have rounded corners. If you add something like a UIVisualEffectView as a subview to this view you likely need to use the same rounded corners on that UIVisualEffectView or it won't have rounded corners.

/// Inspiration: https://stackoverflow.com/a/25475536/129202
class ViewWithRoundedcornersAndShadow: UIView {
    private var theShadowLayer: CAShapeLayer?

    override func layoutSubviews() {
        super.layoutSubviews()

        if self.theShadowLayer == nil {
            let rounding = CGFloat.init(22.0)

            let shadowLayer = CAShapeLayer.init()
            self.theShadowLayer = shadowLayer
            shadowLayer.path = UIBezierPath.init(roundedRect: bounds, cornerRadius: rounding).cgPath
            shadowLayer.fillColor = UIColor.clear.cgColor

            shadowLayer.shadowPath = shadowLayer.path
            shadowLayer.shadowColor = UIColor.black.cgColor
            shadowLayer.shadowRadius = CGFloat.init(3.0)
            shadowLayer.shadowOpacity = Float.init(0.2)
            shadowLayer.shadowOffset = CGSize.init(width: 0.0, height: 4.0)

            self.layer.insertSublayer(shadowLayer, at: 0)
        }
    }
}

回答8:

Just add the following code for corner radius and shadow,you need to give background color to the view, So the shadow doesn't affect the subviews.

      func shadowOnviewWithcornerRadius(YourView:UIView) 
{  
        YourView.layer.shadowColor = UIColor.black.cgColor;
        YourView.layer.shadowOpacity = 0.5;
        YourView.layer.shadowRadius  = 5;
        YourView.layer.shadowOffset  = CGSize(width :0, height :0)
        YourView.layer.masksToBounds = false;
        YourView.layer.cornerRadius  =  2.0;
        YourView.layer.borderWidth   = 0.5;
        YourView.backgroundColor     = UIColor.white;
}