从 collectionView 呈现一个 viewController

Question

我正在扩展 UICollectionView 以创建一个空视图，我无法调用 self.present。有没有更好的方法来处理空视图？我应该如何处理 collectionView 中的 self.present？

extension UICollectionView {
    func setEmptyView() {

        let signUpButton = UIButton(type: .custom)
        signUpButton.addTarget(self, action: #selector(onSignIn), for: .touchUpInside)
    }

    @objc func onSignIn() {
        let viewController = SignInController()
        viewController.modalPresentationStyle = .fullScreen
    
    }
}

Answer 1

您可以从顶级控制器呈现..使用此扩展程序您将获得顶级控制器...

extension UIApplication {

    class func getTopMostViewController() -> UIViewController? {
        let keyWindow = UIApplication.shared.windows.filter {$0.isKeyWindow}.first
        if var topController = keyWindow?.rootViewController {
            while let presentedViewController = topController.presentedViewController {
                topController = presentedViewController
            }
            return topController
        } else {
            return nil
        }
    }
}

然后在您的集合视图扩展中

extension UICollectionView {
    func setEmptyView() {

        let signUpButton = UIButton(type: .custom)
        signUpButton.addTarget(self, action: #selector(onSignIn), for: .touchUpInside)
    }

    @objc func onSignIn() {
        let viewController = SignInController()
        viewController.modalPresentationStyle = .fullScreen
        UIApplication.getTopMostViewController()?.present(viewController, animated: true, completion: nil)
    }

}