如何在真实设备上将Gradient应用于iOS 10中的UIView

我有这个扩展,在Swift中为一个视图添加一个渐变:

extension UIView {
    func addGradientWithColor(colorTop: UIColor, colorButton: UIColor){
        let gradient = CAGradientLayer()
        gradient.frame = self.bounds
        gradient.colors = [colorTop.cgColor, colorButton.cgColor]

        self.layer.insertSublayer(gradient, at: 0)
    }
}

然后,我在我的UIViewController中使用它:

override func viewDidLoad(){
    self.view.addGradientWithColor(colorTop: UIColor.red, colorButton: UIColor.clear)        
    super.viewDidLoad()
}

我运行模拟器,效果很好.但是,当我想在真实设备上使用我的应用程序时,Gradient不起作用.

PD:我尝试了许多方法来做一个Gradient,但在真实设备上没有任何效果.

问题是当视图大小发生变化时,您没有调整图层大小,因此它保持在初始值,这主要取决于视图的创建方式.

我建议使用UIView子类,并更新方法中的图层大小,layoutSubviews在视图调整大小时始终会调用它:

@IBDesignable
open class GradientView: UIView {
    @IBInspectable
    public var startColor: UIColor = .white {
        didSet {
            gradientLayer.colors = [startColor.cgColor, endColor.cgColor]
            setNeedsDisplay()
        }
    }
    @IBInspectable
    public var endColor: UIColor = .white {
        didSet {
            gradientLayer.colors = [startColor.cgColor, endColor.cgColor]
            setNeedsDisplay()
        }
    }

    private lazy var gradientLayer: CAGradientLayer = {
        let gradientLayer = CAGradientLayer()
        gradientLayer.frame = self.bounds
        gradientLayer.colors = [self.startColor.cgColor, self.endColor.cgColor]
        return gradientLayer
    }()

    override init(frame: CGRect) {
        super.init(frame: frame)
        layer.insertSublayer(gradientLayer, at: 0)
    }

    public required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        layer.insertSublayer(gradientLayer, at: 0)
    }

    open override func layoutSubviews() {
        super.layoutSubviews()
        gradientLayer.frame = bounds
    }
}

上面的代码也让你调整Xcode的开始和结束颜色,这样你就可以估计部署时视图的样子.

试试这个,它对我有用.码:

let gradientLayer:CAGradientLayer = CAGradientLayer()
gradientLayer.frame.size = self.gradientView.frame.size
gradientLayer.colors = [UIColor.white.cgColor,UIColor.red.withAlphaComponent(1).cgColor] //Use diffrent colors
gradientLayer.startPoint = CGPoint(x: 0.0, y: 1.0)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 1.0)
self.gradientView.layer.addSublayer(gradientLayer)

有关详细说明,请参阅:渐变在UIView上