how do i set the background color of UIViews to be a gradient color in swift? - swift

Question

Im trying to set the color of my button and labels to a gradient color in swift with the following code:
extension UIView {
func setGradientColor(colorOne: UIColor, colorTwo: UIColor) {
let gradientLayer = CAGradientLayer()
gradientLayer.frame = bounds
gradientLayer.colors = [colorOne.cgColor, colorTwo.cgColor]
gradientLayer.locations = [0.0,0.1]
gradientLayer.startPoint = CGPoint(x: 1.0, y: 1.0)
gradientLayer.endPoint = CGPoint(x: 0.0, y: 0.0)
layer.insertSublayer(gradientLayer, at: 0)
}
}
and then in the sign in form i use the extension like this:
let logo: UILabel = {
let logo = UILabel()
logo.text = "Logo"
logo.setGradientColor(colorOne: UIColor.blue, colorTwo: UIColor.yellow)
logo.textAlignment = .center
logo.font = UIFont.boldSystemFont(ofSize: 59)
return logo
}()
but it still shows up as black.
how do i fix this?

Answer 1

What you posted i review that ... call setGradietColor(colorOne: UIColor.blue, colorTwo: UIColor.yellow) after setting the frame or constraints to the logo view
You can add gradient layer in your view
let gradient: CAGradientLayer = CAGradientLayer()
gradient.colors = [UIColor.black.cgColor, UIColor.blue.cgColor]
gradient.locations = [0.0 , 1.0]
gradient.startPoint = CGPoint(x : 0.0, y : 0)
gradient.endPoint = CGPoint(x :0.0, y: 0.5) // you need to play with 0.15 to adjust gradient vertically
gradient.frame = view.bounds
view.layer.addSublayer(gradient)

Answer 2

You're facing this issue because you're not updating the frame of gradientLayer when bounds of logo updates. For example in ViewController you can give this code if you can have the reference to your gradientLayer.
class ViewController: UIViewController {
var gradient: CAGradientLayer?
let logo: UILabel = {
let logo = UILabel()
logo.text = "Logo"
gradient = logo.setGradietColor(colorOne: UIColor.blue, colorTwo: UIColor.yellow)
logo.textAlignment = .center
logo.font = UIFont.boldSystemFont(ofSize: 59)
return logo
}()
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
gradient?.frame = logo.bounds
}
}
Try returning the layer from your method and modify your function like this:
extension UIView {
#discardableResult
func setGradietColor(colorOne: UIColor, colorTwo: UIColor) {
let gradientLayer = CAGradientLayer()
gradientLayer.frame = bounds
gradientLayer.colors = [colorOne.cgColor, colorTwo.cgColor]
gradientLayer.locations = [0.0,0.1]
gradientLayer.startPoint = CGPoint(x: 1.0, y: 1.0)
gradientLayer.endPoint = CGPoint(x: 0.0, y: 0.0)
layer.insertSublayer(gradientLayer, at: 0)
return layer
}
}