iphone – 在加载Storyboard之前调用应用程序didFinishLaunching

我有一个应用程序,在启动时实现Facebook登录,使用与此完全相似的代码： Facebook Scrumptious Tutorial,除了故事板.

代码的基本要点是,在应用程序启动时,应用程序委托会检查您是否已经登录,如果是,它会直接进入主视图,如果没有,则要求主视图提供登录查看,以便用户可以登录.

我已经解决了我的另一个问题,能够告诉故事板中的主视图呈现不同的视图,从视图heirarchy获取主视图,然后在视图上调用segue.一切正常,但我有一个最后要解决的问题：

据我所知,应用程序didFinishLaunchingWithOptions方法应该在故事板完全加载后调用.但是在我的代码中,如果我试图告诉主视图呈现另一个视图,它会给我一个错误,基本上说它还没有加载(警告：尝试提供< QLoginViewController：0x955c020> on< UINavigationController：0xa28c6e0>其视图不在窗口层次结构中！).

如果我告诉它在延迟后提出视图：

[self performSelector:@selector(showLoginViewAnimated:) withObject:NO afterDelay:.001];

(其中showLoginViewAnimated：是告诉主视图呈现登录视图的方法),然后它工作正常.

任何人都可以帮我弄清楚这里出了什么问题,以及我怎么能解决它？延迟执行选择器显然是一个糟糕的解决方法,因为我永远不知道不同的设备是否可能需要更长的时间才能加载视图…

这是我的appDelegate didFinishLaunchingWithOptions代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.

    self.navigationController = (UINavigationController *)self.window.rootViewController;

    // Navigation Bar Color
    [[UINavigationBar appearance] setTintColor:[UIColor colorWithRed:255.0/255.0 green:128.0/255.0 blue:60.0/255.0 alpha:1.0]];


    /* Facebook Login */    // THIS IS THE RELEVANT CODE: 
    // See if we have a valid token for the current state
    if (FBSession.activeSession.state == FBSessionStateCreatedTokenLoaded) {
        // Yes,valid token exists - open the session (don't display login page)
        [self openSession];
    } else {
        // No,valid token does not exist -  display the login page.
        if ([self.navigationController isViewLoaded]) {
            [self showLoginViewAnimated:NO];   // MY ATTEMPT TO AVOID USING THE DELAY IF POSSIBLE
        }
        else {
            [self performSelector:@selector(showLoginViewAnimated:) withObject:NO afterDelay:.001]; // Delay needed to allow for storyboard loading
        }
    }

    return YES;
}

这是showLoginViewAnimated：代码：

- (void)showLoginViewAnimated:(BOOL)animated
{
    UIViewController *topViewController = [self.navigationController topViewController];
    UIViewController *presentedViewController = [topViewController presentedViewController];

    // If the login screen is not already displayed,display it. If the login screen is
    // displayed,then getting back here means the login in progress did not successfully
    // complete. In that case,notify the login view so it can update its UI appropriately.

    if (![presentedViewController isKindOfClass:[QLoginViewController class]]) {
        if (animated) {
            [topViewController performSegueWithIdentifier:@"ShowLoginViewAnimated" sender:self];
        }
        else {
            [topViewController performSegueWithIdentifier:@"ShowLoginViewStatic" sender:self];
        }
    }
    else {
        QLoginViewController *loginViewController = (QLoginViewController *)presentedViewController;
        [loginViewController loginFailed];
    }
}

在应用程序的原始非故事板版本中,showLoginViewAnimated：方法不会在应用程序didFinishLaunchingWithOptions中调用,直到我已经手动创建了这样的视图：

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.viewController = [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];
self.navController = [[UINavigationController alloc] initWithRootViewController:self.viewController];

self.window.rootViewController = self.navController;
[self.window makeKeyAndVisible];

因此,在我尝试告诉他们提出新观点之前,我已经100％知道这些观点存在.然而,在应用程序的故事板版本中,没有任何代码存在,所以我只需要相信理论上应用程序didFinishLaunchingWithOptions方法在故事板视图完全加载之前不会被调用 – 但是,似乎并非如此.也许它是异步地做它？我不知道…

有任何想法吗？
谢谢你的帮助！

编辑：这是教程中的原始代码,它完全正常 – 几乎完全相同的东西,只是与笔尖.我已经在我的代码中将(BOOL)动画参数添加到了showLoginView方法中,但这是针对别的东西并且没有改变任何东西(我已经检查过).

这是原始(非故事板)appDelegate didFinishLaunchingWithOptions方法：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.viewController = [[FBLViewController alloc] initWithNibName:@"FBLViewController" bundle:nil];
    self.navController = [[UINavigationController alloc] initWithRootViewController:self.viewController];

    self.window.rootViewController = self.navController;
    [self.window makeKeyAndVisible];


    // See if we have a valid Facebook token for the current state
    if (FBSession.activeSession.state == FBSessionStateCreatedTokenLoaded) {
        // Yes,so just open the session (this won't display any UX).
        [self openSession];
    }
    else {
        // No,display the login page.
        [self showLoginView];
    }

    return YES;
}

这是原始(非故事板)showLoginView方法：

- (void)showLoginView
{
    UIViewController *topViewController = [self.navController topViewController];
    UIViewController *presentedViewController = [topViewController presentedViewController];

    // IF the login screen is not already displayed,notify the login view so it can update its UI appropriately.

    if (![presentedViewController isKindOfClass:[FBLLoginViewController class]]) {
        FBLLoginViewController *loginViewController = [[FBLLoginViewController alloc] initWithNibName:@"FBLLoginViewController" bundle:nil];
        loginViewController.delegate = self;
        [topViewController presentViewController:loginViewController animated:NO completion:nil];
    }
    else {
        FBLLoginViewController *loginViewController = (FBLLoginViewController *)presentedViewController;
        [loginViewController loginFailed];
    }
}

[self.window makeKeyAndVisible];