Question

使用此代码，我可以使用渐变添加背景到UIButton：

public func addBackgroundAndGradient(to: UIView, gradient1: CGColor, gradient2: CGColor, cornerRadius: CGFloat = 5){
    let backgroundImage = UIImageView()
    backgroundImage.frame.size = to.frame.size
    backgroundImage.clipsToBounds = true
    backgroundImage.layer.borderColor = UIColor.white.cgColor
    backgroundImage.layer.borderWidth = 0.5
    to.insertSubview(backgroundImage, at: 0)

    let gradient = CAGradientLayer()
        let gradient1 = UIColor(red: 200/255, green: 100/255, blue: 5/255, alpha: 1).cgColor
        let gradient2 = UIColor(red: 1, green: 128/255, blue: 0, alpha: 1).cgColor
        gradient.colors = [gradient1, gradient2, gradient2, gradient1]

    gradient.locations = [0.0, 0.35, 0.65, 1.0]
    gradient.frame.size = to.frame.size
    backgroundImage.layer.addSublayer(gradient)
    backgroundImage.layer.cornerRadius = cornerRadius
}

但是，当我为UIButton设置新标题时，背景将不会调整大小。当文本长于初始时，文本将超出背景。

如何使用UIButton的渐变调整背景大小？

Answer 1

为此，您需要创建自定义UIButton子类，并将CAGradientLayer设置为其图层类：

class ExpandableGradientButton: UIButton {

override class var layerClass: AnyClass {
    get {
            return CAGradientLayer.self
        }
    }
}

然后，您需要将您的功能更改为：

@IBOutlet weak var expandableGradientButton: ExpandableGradientButton!
...
public func addBackgroundAndGradient(to: UIView, gradient1: CGColor, gradient2: CGColor, cornerRadius: CGFloat = 5){
    let backgroundImage = UIImageView()
    backgroundImage.frame.size = to.frame.size
    backgroundImage.clipsToBounds = true
    backgroundImage.layer.borderColor = UIColor.white.cgColor
    backgroundImage.layer.borderWidth = 0.5

    let gradient1 = UIColor(red: 100/255, green: 140/255, blue: 2/255, alpha: 1).cgColor
    let gradient2 = UIColor(red: 123/255, green: 158/255, blue: 54.0/255.0, alpha: 1).cgColor
    if let butonLayer = to.layer as? CAGradientLayer
    {
        butonLayer.colors = [gradient1, gradient2, gradient2, gradient1]
        butonLayer.locations = [0.0, 0.35, 0.65, 1.0]
        butonLayer.cornerRadius = cornerRadius
    }
}

换句话说，您必须使用渐变图层作为UIButton的图层，并且它将自动调整大小。注意：这也可以用于任何其他UIView子类，不仅适用于UIButton。

使用渐变颜色添加调整大小的UIButton背景

1 个答案: