CODEWITHSUNDEEP
calayercagradientlayer
Nick Kohrn
Nick Kohrn

Reputation: 6049

How Can I Make CAGradientLayer Subclass Backing Layer of UIView Subclass

I have created a subclass of CAGradientLayer with desired values for colors, startPoint, and endPoint. It looks like this:

public final class GradientBackgroundLayer: CAGradientLayer {

    // MARK: - Properties

    private let leftColor = UIColor(red: 0.96, 
                                    green: 0.64, 
                                    blue: 0.42, 
                                    alpha: 1.00)

    private let rightColor = UIColor(red: 0.88, 
                                     green: 0.36, 
                                     blue: 0.38, 
                                     alpha: 1.00)

    // MARK: - Initialization

    public override init() {
        super.init()
        configure()
    }

    public override init(layer: Any) {
        super.init(layer: layer)
        configure()
    }

    required public init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    // MARK: - Helpers

    private func configureColors() {
        colors = [leftColor,
                  rightColor]
    }

    private func configureLocations() {
        gradientLayer.locations = [0.1, 
                                   0.9]
        }

    private func configure() {
        configureColors()
        configureLocations()
    }

}

I also have a subclass of UIView that I want to have an instance of GradientBackgroundLayer as its backing layer. It looks like this:

public final class GradientView: UIView {

    // MARK: - Properties

    override public class var layerClass: AnyClass {
        return GradientBackgroundLayer.self
    }

    // MARK: - Initialization

    public override init(frame: CGRect) {
        super.init(frame: frame)
    }

    public required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}

I call call the following initializer in a Playground file:

let view = GradientView(frame: CGRect(x: 0, y: 0, width: 400, height: 100))

I get a black view. I see it update if I change the layer's backgroundColor, but I can't figure out what I am doing incorrectly to cause the layer to not display the gradient.

Upvotes: 1

Views: 217

Answers (1)

Nick Kohrn
Nick Kohrn

Reputation: 6049

It turns out that I forgot to add .cgColor to the gradient's colors when I set the colors property of GradientBackgroundLayer. Adding the required .cgColor to the UIColor instances solved my issue.

Upvotes: 1

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