UIView with gradient not changing colors when button is tapped - ios

Question

When a user clicks on a button, it randomizes the colors used to create a gradient in a large circle. Beneath it are two small circles that display the solid colors used for the gradient. They all display correctly at the start (main circle is a gradient of the randomized smaller circles' color) but when I click on the button, only the smaller circles change color; the large circle stays at the same gradient colors.
Extensions and View Controller:
extension UIView {
func setupGradientBackground(colorOne: UIColor, colorTwo: UIColor) {
let gradientLayer: CAGradientLayer = CAGradientLayer()
gradientLayer.colors = [colorOne.cgColor, colorTwo.cgColor]
gradientLayer.locations = [0.0, 1.0]
gradientLayer.startPoint = CGPoint(x: 0.0, y: 1.0)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.0)
gradientLayer.frame = self.bounds
self.layer.insertSublayer(gradientLayer, at: 0)
}
}
extension UIColor {
static var random: UIColor {
return UIColor(red: .random(in: 0...1), green: .random(in: 0...1), blue: .random(in: 0...1), alpha: 1.0)
}
}
class GradientController: UIViewController {
let gradientView = GradientView()
let leftGradientColor: UIColor = .random
let rightGradientColor: UIColor = .random
}
override func viewDidLoad() {
super.viewDidLoad()
view = gradientView
newGradient()
}
func newGradient() {
gradientView.mainCircleView.setupGradientBackground(colorOne: leftGradientColor, colorTwo: rightGradientColor)
gradientView.colorCircleLeftView.backgroundColor = leftGradientColor
gradientView.colorCircleRightView.backgroundColor = rightGradientColor
gradientView.gradientGenerateButton.addTarget(self, action: #selector(randomGradient(sender:)), for: .touchUpInside)
}
#objc func randomGradient(sender: UIButton)
{
let leftGradient = UIColor.random
let rightGradient = UIColor.random
gradientView.colorCircleLeftView.backgroundColor = leftGradient
gradientView.colorCircleRightView.backgroundColor = rightGradient
//Here is where it's not changing colors. Doesn't seem like the VC recognizes it in this function
gradientView.mainCircleView.setupGradientBackground(colorOne: leftGradient, colorTwo: rightGradient)
}
View:
class GradientView: UIView {
//circle's UIView code in Extensions
let mainCircleView = UIView().circleView(width: 380, height: 380)
let colorCircleLeftView = UIView().circleView(width: 40, height: 40)
let colorCircleRightView = UIView().circleView(width: 40, height: 40)
...
func setupLayout() {
...
}
}
What I've tried is changing the mainCircleView color to solid UIColors, like gradientView.mainCircleView.setupGradientBackground(colorOne: .red, colorTwo: .orange) to see if the main Circle changes to those colors in both func newGradient() and #objc func randomGradient(sender: UIButton). It only changes in func newGradient() what I've set manually, so that means the VC isn't recognizing the main Circle in the #objc func but I'm lost on how to fix it...
Any help is appreciated!
What it looks like when I click the "Generate" button (large circle should be showing brown and purple):

Answer 1

Update your function with this, You have to remove old layer and then insert new Sublayer.
Solution 1 :
func setupGradientBackground(colorOne: UIColor, colorTwo: UIColor) {
if let gradientLayer = (self.layer.sublayers?.compactMap { $0 as? CAGradientLayer })?.first {
gradientLayer.removeFromSuperlayer()
}
let gradientLayer: CAGradientLayer = CAGradientLayer()
gradientLayer.colors = [colorOne.cgColor, colorTwo.cgColor]
gradientLayer.locations = [0.0, 1.0]
gradientLayer.startPoint = CGPoint(x: 0.0, y: 1.0)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.0)
gradientLayer.frame = self.bounds
self.layer.insertSublayer(gradientLayer, at: 0)
}
Solution 2 :
func setupGradientBackground(colorOne: UIColor, colorTwo: UIColor) {
let gradientLayer = layer.sublayers?.first as? CAGradientLayer ?? CAGradientLayer()
gradientLayer.colors = [colorOne.cgColor, colorTwo.cgColor]
gradientLayer.locations = [0.0, 1.0]
gradientLayer.startPoint = CGPoint(x: 0.0, y: 1.0)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.0)
gradientLayer.frame = self.bounds
guard gradientLayer.superlayer != self else {
return
}
layer.insertSublayer(gradientLayer, at: 0)
}
Solution 3 :
you can set name to your CAGradientLayer, This will help you for removing that particular layer.
func setupGradientBackground(colorOne: UIColor, colorTwo: UIColor) {
for layer in layer.sublayers ?? [] {
if layer.name == "GradientLayer" {
layer.removeFromSuperlayer()
}
}
let gradientLayer: CAGradientLayer = CAGradientLayer()
gradientLayer.colors = [colorOne.cgColor, colorTwo.cgColor]
gradientLayer.locations = [0.0, 1.0]
gradientLayer.startPoint = CGPoint(x: 0.0, y: 1.0)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.0)
gradientLayer.name = "GradientLayer"
gradientLayer.frame = self.bounds
self.layer.insertSublayer(gradientLayer, at: 0)
}

Answer 2

The gradient does not change because you add a new gradient below the existing one
extension UIView {
func setupGradientBackground(colorOne: UIColor, colorTwo: UIColor) {
let gradientLayer: CAGradientLayer = CAGradientLayer()
...
// ⬇ There is a mistake.
self.layer.insertSublayer(gradientLayer, at: 0)
}
}
You should change the current gradient with this new one. Or insert a new one above the old one.

Answer 3

Changing the gradient layer colors after setting it
extension CALayer {
func updateGradientColors(_ colors:CGColor...) {
if let layer = sublayers?.first as? CAGradientLayer {
let frame = CGRect(origin: self.bounds.origin, size: CGSize(width: self.bounds.size.width, height: self.bounds.size.height))
layer.frame = frame
layer.colors = colors
}
}
}