How to Apply Gradient to background view of iOS Swift App

Xcode 11 • Swift 5.1

You can design your own Gradient View as follow:

@IBDesignablepublic class Gradient: UIView {    @IBInspectable var startColor:   UIColor = .black { didSet { updateColors() }}    @IBInspectable var endColor:     UIColor = .white { didSet { updateColors() }}    @IBInspectable var startLocation: Double =   0.05 { didSet { updateLocations() }}    @IBInspectable var endLocation:   Double =   0.95 { didSet { updateLocations() }}    @IBInspectable var horizontalMode:  Bool =  false { didSet { updatePoints() }}    @IBInspectable var diagonalMode:    Bool =  false { didSet { updatePoints() }}    override public class var layerClass: AnyClass { CAGradientLayer.self }    var gradientLayer: CAGradientLayer { layer as! CAGradientLayer }    func updatePoints() {        if horizontalMode {            gradientLayer.startPoint = diagonalMode ? .init(x: 1, y: 0) : .init(x: 0, y: 0.5)            gradientLayer.endPoint   = diagonalMode ? .init(x: 0, y: 1) : .init(x: 1, y: 0.5)        } else {            gradientLayer.startPoint = diagonalMode ? .init(x: 0, y: 0) : .init(x: 0.5, y: 0)            gradientLayer.endPoint   = diagonalMode ? .init(x: 1, y: 1) : .init(x: 0.5, y: 1)        }    }    func updateLocations() {        gradientLayer.locations = [startLocation as NSNumber, endLocation as NSNumber]    }    func updateColors() {        gradientLayer.colors = [startColor.cgColor, endColor.cgColor]    }    override public func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {        super.traitCollectionDidChange(previousTraitCollection)        updatePoints()        updateLocations()        updateColors()    }}

The Colors you're providing to gradient must be of type CGColor. So set your array of CGColor to gl.colors.

The correct code is :

class Colors {    var gl:CAGradientLayer!    init() {        let colorTop = UIColor(red: 192.0 / 255.0, green: 38.0 / 255.0, blue: 42.0 / 255.0, alpha: 1.0).cgColor        let colorBottom = UIColor(red: 35.0 / 255.0, green: 2.0 / 255.0, blue: 2.0 / 255.0, alpha: 1.0).cgColor        self.gl = CAGradientLayer()        self.gl.colors = [colorTop, colorBottom]        self.gl.locations = [0.0, 1.0]    }}

Just modifying the above mentioned answer.

func setGradientBackground() {    let colorTop =  UIColor(red: 255.0/255.0, green: 149.0/255.0, blue: 0.0/255.0, alpha: 1.0).cgColor    let colorBottom = UIColor(red: 255.0/255.0, green: 94.0/255.0, blue: 58.0/255.0, alpha: 1.0).cgColor                    let gradientLayer = CAGradientLayer()    gradientLayer.colors = [colorTop, colorBottom]    gradientLayer.locations = [0.0, 1.0]    gradientLayer.frame = self.view.bounds                self.view.layer.insertSublayer(gradientLayer, at:0)}

Then call this method within viewWillAppear

override func viewWillAppear(_ animated: Bool) {    setGradientBackground()    super.viewWillAppear(animated)}