ios - Swift 通用函数来推送任何 View Controller

Question

我正在尝试编写一个函数，1)实例化 UIViewController 的子类，2)推送到调用者 UIViewController 的导航 Controller 中。

到目前为止，我有这个:

func pushAnyViewController<T>(viewController:T, storyboardName:String) {
    // Instantiate the view controller of type T
    guard let nextViewController = UIStoryboard(name: storyboardName, bundle: nil).instantiateViewController(withIdentifier: String(describing: T.self)) as? T else {
        return
    }      
    
    viewController.navigationController.pushViewController(nextViewController, animated: true)
}

这会产生错误

Value of type 'T' has no member 'navigationController'

我不确定是否应该说 T 永远是 UIViewController 的子类。如果是这样的话，我不清楚我在哪里这样做。为此，我想到了:

func pushAnyViewController<T>(viewController:T & UIViewController, storyboardName:String)

但这会产生错误:

Generic parameter 'T' is not used in function signature

Non-protocol, non-class type 'T' cannot be used within a protocol-constrained type

Answer 1

您需要确定T是一个带有 <T:UIViewController> 的 vc

func pushAnyViewController<T:UIViewController>(viewController:T, storyboardName:String) {
    guard let nextViewController = UIStoryboard(name: storyboardName, bundle: nil).instantiateViewController(withIdentifier: String(describing: T.self)) as? T else { return } 
    viewController.navigationController?.pushViewController(nextViewController, animated: true)
}