Firebase + Swift：绕过用户登录屏幕

Question

因此，我正在开发一款新应用，并且我正在使用Firebase来管理用户登录等所有后端内容，我为用户创建了登录/注册屏幕他们加载应用程序。我想要做的是加载HomeScreenVC，如果用户已经登录，如果用户不是，那么他们会被引导到登录/注册vc。

如果用户已经是currentUser，但它的工作原理，我有种工作，但我遇到的问题是，如果用户从未加载应用程序然后崩溃，因为它无法检测currentUser 。

我的代码我在AppDelegate的是：

var window: UIWindow? 
var storyboard: UIStoryboard? 


func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { 
    // Override point for customization after application launch. 
    FIRApp.configure() 

    self.storyboard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle()) 
    let currentUser = FIRAuth.auth()?.currentUser! 
    if currentUser != nil 
    { 
     self.window?.rootViewController = self.storyboard?.instantiateViewControllerWithIdentifier("tabVC") 
    } 
    else 
    { 
     self.window?.rootViewController = self.storyboard?.instantiateViewControllerWithIdentifier("loginScreen") 
    } 
    return true 
} 

这是错误我得到：here

任何帮助将是巨大的！我使用的是Firebase和Swift 2的最新版本。

Answer 1

您正在强制展开零线，导致崩溃。卸下!从FIRAuth.auth()?.currentUser!

Answer 2

更新迅速3和火力4.8

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool { 
    UIApplication.shared.statusBarStyle = .lightContent 
    // Override point for customization after application launch. 
    // add firebase 
    FirebaseApp.configure() 

    // check user status then set initial Viewcontroller 

    self.window = UIWindow(frame: UIScreen.main.bounds) 
    let storyboard = UIStoryboard(name: "Main", bundle: nil) 
    let startMainVC = storyboard.instantiateViewController(withIdentifier: "MainVC") 
    let startIntroVC = storyboard.instantiateViewController(withIdentifier: "IntroVC") 

    // check if user is logged 
    if authProvider.Instance.userStatus() == true{ 

     self.window?.rootViewController = startMainVC 
    } 
    else 
    { 
     self.window?.rootViewController = startIntroVC 
    } 

    return true 
}