Question

我正在尝试以编程方式更改我的应用的根ViewController。一旦用户注册我想要不同的根ViewController。这是我的代码

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "tabBarVC")

UIApplication.shared.keyWindow?.rootViewController = vc
UIApplication.shared.keyWindow?.makeKeyAndVisible()

self.present(vc, animated: true, completion: nil)

在呈现vc之后我杀了应用程序，当我再次运行它时，根ViewControler是相同的。我究竟做错了什么？我也在AppDelegate中尝试了相同的代码，但没有成功。

Answer 1

根据当前应用设置在appDelegate的didFinishLaunchingWithOptions方法中设置此项，您也应使用window而不是keyWindow

if(userExists)
{
   let vc = storyboard.instantiateViewController(withIdentifier: "tabBarVC")

   UIApplication.shared.window.first?.rootViewController = vc

}
else
{
   let vc = storyboard.instantiateViewController(withIdentifier: "loginVC")

   UIApplication.shared.window.first?.rootViewController = vc
}

不要使用礼物，因为这会自动更改根

另一种访问窗口的方法（在AppDelegate有值时使用）

let appDelegate = UIApplication.shared.delegate as? AppDelegate
let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
let homeController =  mainStoryboard.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController
appDelegate?.window?.rootViewController = homeController

以编程方式更改根ViewController

1 个答案: