Accessing a view controller created through Storyboard using the App Delegate

Question

I'm working on an iOS5 app using storyboard, and I have a method in a view controller class that i'd like to access from the App Delegate. The trouble is, this view controller gets instantiated via a tab bar controller in storyboard, so the App Delegate has no direct way of calling the method I want...

For a view controller to get in touch with the App Delegate, all one has to do is use:

MyAppDelegate *appDelegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];

Is there a similarly easy way of pointing to an already-instantiated view controller or class?

score 15 · Answer 1 · answered Jan 09 '12 at 16:47

Thanks to Jerry (above), here's the code that got me what I wanted:

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

//check to see if navbar "get" worked
if (navigationController.viewControllers) 

    //look for the nav controller in tab bar views 
    for (UINavigationController *view in navigationController.viewControllers) {

        //when found, do the same thing to find the MasterViewController under the nav controller
        if ([view isKindOfClass:[UINavigationController class]])
            for (UIViewController *view2 in view.viewControllers) 
                if ([view2 isKindOfClass:[MasterViewController class]])                    
                    result = (MasterViewController *) view2;
}

score 10 · Answer 2 · answered Nov 03 '12 at 22:40

I probably would do it in reverse. Create a method in AppDelegate call registerViewController or something. In every ViewController, call the method with itself with a name. Then in AppDelegate, you can do whatever you want afterward. It is messy to do all sort of drill

In AppDelegate

- (void)registerViewController:(NSString *)name controller:(UIViewController *)controller
{
    if(_viewControllers == nil)
    {
        _viewControllers = [[NSMutableDictionary alloc] init];

    }

    [_viewControllers setObject:controller forKey:name];
}

In any ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    [appDelegate registerViewController:@"feelings" controller:self];
}

In AppDelegate

XViewController *vc = (XViewController *)[_viewControllers objectForKey:@"X"];
[X startSpinner];

Hope this help

BS

great idea,but XViewController should be remove from _viewControllers when dealloc and I must remember many keys if there are many view controllers I need to access in app delegate. — Nick, Nov 05 '13 at 08:18

score 10 · Accepted Answer · edited Aug 28 '14 at 09:40

10

You'll have to traverse the view hierarchy from the app delegate. Assuming the AppDelegate holds a reference to the UITabBarController, you could use the viewControllers property or selectedViewController property to get to your view controller.

edited Aug 28 '14 at 09:40

Rinju Jain

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answered Jan 09 '12 at 05:13

Jerry

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So...an outlet from the tab bar in storyboard to the app delegate, and then figure out the tab bar's properties to find the view controller I need? Any reason not to just create a direct outlet from the view controller itself, since that's in storyboard too? – Amos Jan 09 '12 at 05:35
6

Ok, there is no way to create an outlet to the app delegate from the storyboard, so my statement was a little incorrect. There is a window property on the app delegate that is set automatically by the storyboard and it has a rootViewController property. That will be the first view controller in the storyboard. From there you should be able to get to the view you need. – Jerry Jan 09 '12 at 13:45
Bam! That did it...though it is a bit of a pain traversing all the views. Thanks, Jerry! – Amos Jan 09 '12 at 16:44
@jerry can u suggest some solution for a similar issue of mine. http://stackoverflow.com/questions/21373470/access-a-view-controller-from-appdelgate-using-storyboard – Suraj K Thomas Jan 31 '14 at 10:18

score 7 · Answer 4 · edited Apr 18 '14 at 11:28

7

If you are using a storyboard, and you want instance of a viewController in storyboard you can use the following

UIStoryboard *mystoryboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
id viewcontroller = [mystoryboard instantiateViewControllerWithIdentifier:@"identifier"];

Here the 'identifier' is the name provided in the particular viewController's 'storyBoard ID' in 'Identity' section in 'Identity Inspector'.

edited Apr 18 '14 at 11:28

Dilip Manek

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answered Jan 23 '14 at 05:37

infiniteLoop

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This worked great. Would you have any guidance on how to also load my tab bar and navigation controllers? – mreynol Dec 11 '14 at 23:51

score 6 · Answer 5 · edited Sep 17 '15 at 13:45

6

I have a better solution. You can use window.rootViewController.storyboard to get a reference to the storyboard of that view.

edited Sep 17 '15 at 13:45

Stéphane Bruckert

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answered Nov 16 '12 at 16:09

Steffen Brem

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score 2 · Answer 6 · answered Oct 26 '12 at 11:39

In the AppDelegate, you could simply use indexes to access the controllers via UITabBarController:

UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController;
firstViewController = [[tabBarController viewControllers] objectAtIndex:0];
secondViewController = [[tabBarController viewControllers] objectAtIndex:1];
thirdViewController = [[tabBarController viewControllers] objectAtIndex:2];

Naturally, this will get messed up if you change the ordering of the tab bar. Also, if you're looking for a controller deeper in the hierarchy, you need to do a bit more legwork.

score 1 · Answer 7 · edited May 23 '17 at 12:02

Swift

This is the Swift version of @infiniteLoop's answer.

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let myViewController = storyboard.instantiateViewControllerWithIdentifier("identifier") as! MyViewController

You need to replace the storyboard name, view controller name, and view controller identifier with whatever you used in your project.

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Accessing a view controller created through Storyboard using the App Delegate

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