ios - Xcode/Swift 为所有同名按钮添加渐变层

Question

Xcode/Swift 如此新颖，我正在为应用程序中不同 View Controller 中的一堆按钮添加渐变层。我想知道是否有一种方法可以同时定位所有具有特定名称的按钮，而不是将我的代码单独添加到每个页面中。这是我的渐变代码:

let gradientLayer = CAGradientLayer()
gradientLayer.frame = self.btnSavePhoto.bounds

let color1 = UIColor(red:0.05, green:0.29, blue:0.49, alpha: 1.0).CGColor as CGColorRef
let color2 = UIColor(red:0.08, green:0.23, blue:0.39, alpha: 1.0).CGColor as CGColorRef

gradientLayer.colors = [color1, color2]

gradientLayer.locations = [0.0, 1.0]

self.btnSavePhoto.layer.addSublayer(gradientLayer)

Answer 1

您可以创建一个自定义类，使您的 UIButton 像这样以某种方式带有渐变

对于 Swift 3

import UIKit

public class GradientButton: UIButton {

    override public func layoutSubviews() {
        super.layoutSubviews()
        layoutGradientButtonLayer()
    }

    // MARK: Private
    private func layoutGradientButtonLayer() {
        let gradientLayer = CAGradientLayer()
        let color1 = UIColor(red:0.05, green:0.29, blue:0.49, alpha: 1.0).cgColor as CGColor
        let color2 = UIColor(red:0.08, green:0.23, blue:0.39, alpha: 1.0).cgColor as CGColor
        gradientLayer.colors = [color1, color2]
        gradientLayer.locations = [0.0, 1.0]
        self.layer.addSublayer(gradientLayer)
    }
}

对于 Swift 2.3

import UIKit

public class GradientButton: UIButton {

    override public func layoutSubviews() {
        super.layoutSubviews()
        layoutGradientButtonLayer()
    }

    // MARK: Private
    private func layoutGradientButtonLayer() {
         let gradientLayer = CAGradientLayer()
         let color1 = UIColor(red:0.05, green:0.29, blue:0.49, alpha: 1.0).CGColor as CGColorRef
         let color2 = UIColor(red:0.08, green:0.23, blue:0.39, alpha: 1.0).CGColor as CGColorRef
         gradientLayer.colors = [color1, color2]
         gradientLayer.locations = [0.0, 1.0]
         self.layer.addSublayer(gradientLayer)
    }
}

然后在按钮的检查器中，您可以将类设置为 GradientButton 检查图像

这样你就不需要为渐变按钮编写代码了。