有条件地从AppDelegate的情节提要中的不同位置开始

Question

我有一个故事板设置了正常的登录名和主视图控制器，主视图控制器是登录成功后用户导航到的视图控制器。我的目标是如果身份验证（存储在钥匙串中）成功，则立即显示主视图控制器，如果身份验证失败，则显示登录视图控制器。基本上，我想在AppDelegate中执行以下操作：

// url request & response work fine, assume success is a BOOL here

// that indicates whether login was successful or not

if (success) {

          // 'push' main view controller

} else {

          // 'push' login view controller

}

我知道方法performSegueWithIdentifier：但是该方法是UIViewController的实例方法，因此无法从AppDelegate中调用。如何使用现有的情节提要板来完成此任务？

编辑：

情节提要的初始视图控制器现在是导航控制器，没有连接任何东西。我使用了setRootViewController：区别，因为MainIdentifier是UITabBarController。这就是我的代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{        

    BOOL isLoggedIn = ...;    // got from server response

    NSString *segueId = isLoggedIn ? @"MainIdentifier" : @"LoginIdentifier";

    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Storyboard" bundle:nil];

    UIViewController *initViewController = [storyboard instantiateViewControllerWithIdentifier:segueId];

    if (isLoggedIn) {

        [self.window setRootViewController:initViewController];

    } else {

        [(UINavigationController *)self.window.rootViewController pushViewController:initViewController animated:NO];

    }

    return YES;

}

欢迎提出建议/改进！

Answer 1

我假设您的情节提要板被设置为“主情节提要板”（UIMainStoryboardFileInfo.plist中的键）。在这种情况下，UIKit将加载情节提要，并将其初始视图控制器设置为窗口的根视图控制器，然后再发送application:didFinishLaunchingWithOptions:到AppDelegate。我还假设情节提要中的初始视图控制器是导航控制器，您要将主视图或登录视图控制器推入该导航控制器。您可以向窗口询问其根视图控制器，并将performSegueWithIdentifier:sender:消息发送给它：NSString *segueId = success ? @"pushMain" : @"pushLogin";[self.window.rootViewController performSegueWithIdentifier:segueId sender:self];

Answer 2

我对这里提出的一些解决方案感到惊讶。故事板中实际上不需要虚拟的导航控制器，无需在viewDidAppear：或任何其他黑客上隐藏视图并触发segues。如果没有在plist文件中配置情节提要，则必须自己创建窗口和根视图控制器：- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{            BOOL isLoggedIn = ...;    // from your server response    NSString *storyboardId = isLoggedIn ? @"MainIdentifier" : @"LoginIdentifier";    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Storyboard" bundle:nil];    UIViewController *initViewController = [storyboard instantiateViewControllerWithIdentifier:storyboardId];    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    self.window.rootViewController = initViewController;    [self.window makeKeyAndVisible];    return YES;}如果在应用程序的plist中配置了故事板，则在调用application：didFinishLaunching：时将已经设置了窗口和根视图控制器，并且将在窗口上为您调用makeKeyAndVisible。在这种情况下，它甚至更简单：- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{            BOOL isLoggedIn = ...;    // from your server response    NSString *storyboardId = isLoggedIn ? @"MainIdentifier" : @"LoginIdentifier";    self.window.rootViewController = [self.window.rootViewController.storyboard instantiateViewControllerWithIdentifier:storyboardId];    return YES;}

Answer 3

如果您的情节提要的入口点不是UINavigationController：- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    //Your View Controller Identifiers defined in Interface Builder    NSString *firstViewControllerIdentifier  = @"LoginViewController";    NSString *secondViewControllerIdentifier = @"MainMenuViewController";    //check if the key exists and its value    BOOL appHasLaunchedOnce = [[NSUserDefaults standardUserDefaults] boolForKey:@"appHasLaunchedOnce"];    //if the key doesn't exist or its value is NO    if (!appHasLaunchedOnce) {        //set its value to YES        [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"appHasLaunchedOnce"];        [[NSUserDefaults standardUserDefaults] synchronize];    }    //check which view controller identifier should be used    NSString *viewControllerIdentifier = appHasLaunchedOnce ? secondViewControllerIdentifier : firstViewControllerIdentifier;    //IF THE STORYBOARD EXISTS IN YOUR INFO.PLIST FILE AND YOU USE A SINGLE STORYBOARD    UIStoryboard *storyboard = self.window.rootViewController.storyboard;    //IF THE STORYBOARD DOESN'T EXIST IN YOUR INFO.PLIST FILE OR IF YOU USE MULTIPLE STORYBOARDS    //UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"YOUR_STORYBOARD_FILE_NAME" bundle:nil];    //instantiate the view controller    UIViewController *presentedViewController = [storyboard instantiateViewControllerWithIdentifier:viewControllerIdentifier];    //IF YOU DON'T USE A NAVIGATION CONTROLLER:    [self.window setRootViewController:presentedViewController];    return YES;}如果您的情节提要的入口点是UINavigationController替换项：//IF YOU DON'T USE A NAVIGATION CONTROLLER:[self.window setRootViewController:presentedViewController];与：//IF YOU USE A NAVIGATION CONTROLLER AS THE ENTRY POINT IN YOUR STORYBOARD:UINavigationController *navController = (UINavigationController *)self.window.rootViewController;[navController pushViewController:presentedViewController animated:NO];