Question

要跳过登录（如果用户已登录），我正在使用用户默认值，并且在应用程序委托中，我正在调用主视图控制器，但问题是数据没有像错误一样显示为nil错误Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value in swreal view controller

这里是我的代码

 if UserDefaults.standard.bool(forKey: "login") {
        //YES Already Login

        self.window = UIWindow(frame:UIScreen.main.bounds)
                    let storyboard = UIStoryboard.init(name: "Main", bundle: nil)
                    let viewController = storyboard.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController
                    let navigationController = UINavigationController.init(rootViewController: viewController)
                    self.window?.rootViewController = navigationController
                    self.window?.makeKeyAndVisible()
    } else {
        //NOT Login
        self.window = UIWindow(frame:UIScreen.main.bounds)
                    let storyboard = UIStoryboard.init(name: "Main", bundle: nil)
                    let viewController = storyboard.instantiateViewController(withIdentifier: "signinpage") as! ViewController
                    let navigationController = UINavigationController.init(rootViewController: viewController)
                    self.window?.rootViewController = navigationController
                    self.window?.makeKeyAndVisible()
    }

，然后跳过登录到第3行中显示的home nil值的操作。自我看法...

super.viewDidLoad()
    menuButton.target = self.revealViewController()
    menuButton.action = #selector(SWRevealViewController.revealToggle(_:))
    self.view.addGestureRecognizer(self.revealViewController().panGestureRecognizer())

 @IBAction func logoutButton(_ sender: Any) {


    let alert = UIAlertController(title: "Alert", message: "Are you Sure You want to Logout", preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { action in
        GIDSignIn.sharedInstance().signOut()
        let secondViewController = self.storyboard?.instantiateViewController(withIdentifier: "signinpage") as! ViewController
        UserDefaults.standard.set(false, forKey: "login")
        self.navigationController?.setViewControllers([secondViewController], animated: true)
    }))
    alert.addAction(UIAlertAction(title: "Cancel", style: .default, handler:nil))
    self.present(alert, animated: true, completion: nil)



}

Answer 1

首先检查您的故事板ID ，是否正确。您可以检查以下代码以获取更多信息。希望它可以帮助您解决问题。

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        if UserDefaults.standard.object(forKey: "login") != nil {
                    let storyboard = UIStoryboard(name: "Main", bundle: nil)
                    let viewController: HomeViewController = storyboard.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController
                    let mainViewController = storyboard.instantiateViewController(withIdentifier: "MainViewController") as! MainViewController
                    let navigationController = storyboard.instantiateViewController(withIdentifier: "NavigationController") as! NavigationController
                    navigationController.setViewControllers([viewController], animated: false)
                    mainViewController.rootViewController = navigationController
                    let window = UIApplication.shared.delegate!.window!
                    window!.rootViewController = mainViewController
                    UIView.transition(with: window!, duration: 0.3, options: [.transitionCrossDissolve], animations: nil, completion: nil)
                }
        }

Answer 2

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
     // Override point for customization after application launch.

     //Check that user login or not        
     if let isLogin = UserDefaults.standard.object(forKey: "login") as? Bool {

        //If already login then show Dashboard screen    
        self.showDashboardScreen()
     } else {

        //If not login then show Login screen
        self.showLoginScreen()
     }

     return true 
}

func showLoginScreen() {

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let loginViewController: LoginViewController = storyboard.instantiateViewController(withIdentifier: "#LoginViewControllerStoryboardID") as! LoginViewController

     var navigationController = UINavigationController()
     navigationController = UINavigationController(rootViewController: loginViewController)

     //It removes all view controllers from the navigation controller then sets the new root view controller and it pops.
     window?.rootViewController = navigationController

     //Navigation bar is hidden
     navigationController.isNavigationBarHidden = true 
}

func showDashboardScreen() {

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let dashboardViewController: DashboardViewController = storyboard.instantiateViewController(withIdentifier: "#DashboardViewControllerStoryboardID") as! DashboardViewController

     var navigationController = UINavigationController()
navigationController = UINavigationController(rootViewController: dashboardViewController)

     //It removes all view controllers from the navigation controller then sets the new root view controller and it pops.
     window?.rootViewController = navigationController

     //Navigation bar is hidden
     navigationController.isNavigationBarHidden = true 
 }

Answer 3

根据我的观察， self.revealViewController()为零。为了确保它是否为零，请在第三行添加一个断点，并通过在控制台中打印self.revealViewController（）

po self.revealViewController()

如果为零，请参阅以下链接：

Self.revealViewController() returns nil

https://github.com/John-Lluch/SWRevealViewController/issues/627

https://www.codebeaulieu.com/programming/2017/5/5/a-cleaner-swrevealviewcontroller-implementation-using-swift-extensions

另外，显示您用于配置SWRevealcontroller的代码。

Answer 4

更改此代码

self.window = UIWindow(frame:UIScreen.main.bounds)
                let storyboard = UIStoryboard.init(name: "Main", bundle: nil)
                let viewController = storyboard.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController
                let navigationController = UINavigationController.init(rootViewController: viewController)
                self.window?.rootViewController = navigationController
                self.window?.makeKeyAndVisible()

对此：

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewController(withIdentifier: "SWRevealViewController")
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()

假设

您有一个类型为SWRevealViewController的导航控制器，其sw_front上有HomeViewController标记，或者前面有一个NavigationController，而菜单VC上有sw_rear。因此，您必须实例化SWRevealViewController才能显示菜单，因为您的代码直接进入主屏幕，因此SWRevealViewController为nil，因为它没有在HomeViewController之前实例化。

PD：这是一个示例，说明了如何在项目中使用上面的代码进行计算并在身份检查器中进行设置

Answer 5

您可以使用多故事板概念。

登录故事板

家庭情节提要

+(void) LoginHomeScreen:(NSString*)strController andIndex:(int)index 
{ 
     NSData *data = [[NSUserDefaults standardUserDefaults] dataForKey:USERDETAILS];

     NSDictionary *userData = [NSKeyedUnarchiver unarchiveObjectWithData:data];

     if (userData != NULL && [userData count] > 0) {
         //DashboardVC
         UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Home" bundle:nil];
         UINavigationController *navigationController = [storyboard instantiateViewControllerWithIdentifier:@"SideMenuNavigationVC"];
         [navigationController setViewControllers:@[[storyboard instantiateViewControllerWithIdentifier:strController]]];

         LGSideMenuController *mainViewController = [storyboard instantiateInitialViewController];
         mainViewController.rootViewController = navigationController;

         UIViewController * SideMenu = [storyboard instantiateViewControllerWithIdentifier:@"SideMenuVC"];
         mainViewController.leftViewController = SideMenu;
         mainViewController.leftViewPresentationStyle = LGSideMenuPresentationStyleSlideBelow;

         UIWindow *window = UIApplication.sharedApplication.delegate.window;
         window.rootViewController = mainViewController;

         [UIView transitionWithView:window duration:0.3 options:UIViewAnimationOptionTransitionCrossDissolve animations:nil completion:nil];

     } else {
         UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
         LoginVC *loginVC = (LoginVC *)[storyboard instantiateViewControllerWithIdentifier:@"LoginVC"];
         UINavigationController *navLogin = [[UINavigationController alloc] initWithRootViewController:loginVC];
         navLogin.navigationBar.hidden = true;
         [[UIApplication sharedApplication].delegate.window setRootViewController:navLogin];
     }
}

如果用户已经迅速登录，如何跳过登录

5 个答案: