swift - 从 C 导入的扩展结构

Question

我是 Swift 的新手，我有这个扩展：

extension UIView.KeyframeAnimationOptions {
    init(animationOptions: UIView.AnimationOptions) {
        rawValue = animationOptions.rawValue
    }
}

由于 Swift 4.2rawValue = animationOptions.rawValue产生了这个警告：

Initializer for struct 'UIView.KeyframeAnimationOptions' must use "self.init(...)" or "self = ..." because the struct was imported from C

我使用这样的扩展名：

UIView.animateKeyframes(withDuration: 1.2, delay: 0.0, options: [.repeat, UIView.KeyframeAnimationOptions(animationOptions: .curveEaseOut)], animations: {
...
}

如何从 中修复此警​​告消息struct was imported from C？

Answer 1

Answer 2

你的代码从来都不正确。它应该是：

extension UIView.KeyframeAnimationOptions {
    init(animationOptions: UIView.AnimationOptions) {
        self.init(rawValue: animationOptions.rawValue)
    }
}

但是，这是个坏主意。您将一个枚举的选项强制转换为一个不相关的枚举。这将导致问题。