Programmatically set rootViewcontroller for UINavi

问题:

I have a value in NSUserdefaults. I am using storyboard, it is embedded in UINavigationController.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
     if([[NSUserDefaults standardUserDefaults]objectForKey:@"isLoggedIn"]){
         //show home page here
        }else{
           // show login view
        }
}

I can open the app using a URL also

- (BOOL)application:(UIApplication *)application handleOpenURL:(NSURL *)url {
         NSString *text = [[url host] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

         if(text.length > 0){
           // show home page 

         }else {
          // show settings page
        }

        return YES;
}

How can I set the rootViewController for the UINavigationController based on the value that is retrieved .Can anyone please help me out?

回答1:

You can create an object of UINavigationController with your ViewController as per if/else condition and set the navigation controller as rootViewController property of window in AppDelegate as follows:

LoginViewController *loginController = [[UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil] instantiateViewControllerWithIdentifier:@"loginController"]; //or the homeController
UINavigationController *navController = [[UINavigationController alloc]initWithRootViewController:loginController];
self.window.rootViewController = navController;

回答2:

This is what i used in my code

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    // Get user preference
 NSString * wxyz=[defaults stringForKey:@"wxyz"];
    //Get value at wxyz field

if ([self isInValidwxyz:wxyz]) {
    //check if wxyz is invalid
    //If wxyz is invalid, write custom code
}
else{
    //if valid, 
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone){
        UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"myStoryBoardiPhone" bundle:nil];
        self.window.rootViewController = [storyboard instantiateInitialViewController];
    }
    else{

        UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"myStoryBoardiPad" bundle:nil];
        self.window.rootViewController = [storyboard instantiateInitialViewController];;
    }
    [self.window makeKeyAndVisible];
}

and then, go through this link for implementation with navigation controller