Question

I am learning iOS and developing my first iPone app. I want to add a feature to my app: if a user has login before, I want to redirect the user to the main view. otherwise, I want to redirect the user to the login view.

I have read ios change storyboard default view controller at run time, but I am wondering whether I can write the code that decides the root view in AppDelegate. Therefore, I won’t have a view that is never launched.

this is my code in AppDelegate:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

    [[UIApplication sharedApplication] registerForRemoteNotificationTypes:
     (UIRemoteNotificationTypeSound | UIRemoteNotificationTypeAlert)];


    MainViewController *rootVC = [[MainViewController alloc] init];
    if (userNeverLogin) {
       LoginViewController *rootVC = [[LoginViewController alloc] init];
    }

    self.window.rootViewController = [[UINavigationController alloc] initWithRootViewController:rootVC];
    return YES;
}

this code doesn’t work (it will not trigger any error, but it will show nothing in the simulator). how should I revise it? Or it’s impossible to do this feature in AppDelegate?

I am sorry that I am a newbie to iOS. I hope this question is not stupid.

Answer 1

I finally found out the answer from @followben in Conditionally start at different places in storyboard from AppDelegate is actually the one I want.
this is sample code from him:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{        
    BOOL isLoggedIn = ...;    // from your server response

    NSString *segueId = isLoggedIn ? @"MainIdentifier" : @"LoginIdentifier";
    self.window.rootViewController = [self.window.rootViewController.storyboard instantiateViewControllerWithIdentifier:segueId];

    return YES;
}

the way to set view controller identifier:

I gave both @ekims and @X Slash a +1 for your inspiring discussion.
thank you guys sincerely.