使用自动布局为 UIView 应用渐变背景 [英] Applying gradient background for UIView using auto layout
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问题描述
我扩展了 UIView 以添加一个 addGradientWithColor() 方法来获取渐变背景:
I extended UIView to add a addGradientWithColor() method to get the gradient background:
extension UIView {
func addGradientWithColor() {
let gradient = CAGradientLayer()
gradient.frame = self.bounds
gradient.colors = [gradientEndColor.CGColor, gradientStartColor.CGColor]
gradient.startPoint = CGPointMake(1,0)
gradient.endPoint = CGPointMake(0.2,1)
self.layer.insertSublayer(gradient, atIndex: 0)
} }
我的问题是当我运行横向模式时,UIView 没有被拉伸
My issue is when I run landscape mode, the UIView is not stretched
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
self.view.addGradientWithColor() }
我尝试调用 viewDidLayoutSubviews() 但它无法正常工作
I tried to calling viewDidLayoutSubviews() but its not working properly
这是屏幕截图:
删除 viewDidLayoutSubviews() 后
after removing viewDidLayoutSubviews()
推荐答案
您可以子类化 UIView 并覆盖添加渐变的 drawRect 方法.
You can subclass the UIView and override drawRect method where you add your gradient.
更新到 Swift 4
class GradientView: UIView {
private let gradient : CAGradientLayer = CAGradientLayer()
private let gradientStartColor: UIColor
private let gradientEndColor: UIColor
init(gradientStartColor: UIColor, gradientEndColor: UIColor) {
self.gradientStartColor = gradientStartColor
self.gradientEndColor = gradientEndColor
super.init(frame: .zero)
}
required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") }
override func layoutSublayers(of layer: CALayer) {
super.layoutSublayers(of: layer)
gradient.frame = self.bounds
}
override public func draw(_ rect: CGRect) {
gradient.frame = self.bounds
gradient.colors = [gradientEndColor.cgColor, gradientStartColor.cgColor]
gradient.startPoint = CGPoint(x: 1, y: 0)
gradient.endPoint = CGPoint(x: 0.2, y: 1)
if gradient.superlayer == nil {
layer.insertSublayer(gradient, at: 0)
}
}
}
创建 UIView 后,您只需要将约束添加到该视图.
After you create your UIView you just need to add your constraints to that view.
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