Executing ViewController's methods from UINavigationController - objective-c

Question

I have created several ViewControllers in a storyboard that each have their own class files. In AppDelegate I have programatically generated a UINavigationController that exists at the top of the app for every page. This will have two buttons that will be the same for every ViewController, one will load a ViewController called 'settings' and one will fire a method that reveals a side menu.
Screen shots to illustrate:
Currently, each ViewController has a button in the top left, that when pressed moves the current ViewController across revealing the menu below.
This works fine but what I want is for this button to be removed and replaced with the button that is on the NavigationController (currently place holder menu button seen in the purple NavigationController).
How do I implement the code that moves the ViewController in the AppDelegate, what the UINavigationController is generated?
AppDelegate.m
#implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:#"Main" bundle: nil];
MainViewController* mainVC = [mainStoryboard instantiateInitialViewController];
UINavigationController *navVC = [[UINavigationController alloc] initWithRootViewController:mainVC];
[mainVC setTitle:#"Congress app"];
UIBarButtonItem *showSettingsButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:self action:#selector(showSettings:)];
UIBarButtonItem *showMenuButton = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:#"menuButton.png"] style:UIBarButtonItemStylePlain target:self action:#selector(revealMenu:)];
mainVC.navigationItem.leftBarButtonItem = showMenuButton;
mainVC.navigationItem.rightBarButtonItem = showSettingsButton;
[self.window setRootViewController:navVC];
[_window makeKeyAndVisible];
return YES;
}
- (IBAction)revealMenu:(id)sender
{
// This obviously won't work but what should go here instead?
// Something like get instance of MainViewController and fire it's reveal menu
// method but passing the current ViewController Id and running slidingViewController anchorTopViewTo:ECRight on that?
[self.slidingViewController anchorTopViewTo:ECRight];
}
MainViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
self.view.layer.shadowOpacity = 0.75f;
self.view.layer.shadowRadius = 10.0f;
self.view.layer.shadowColor = [UIColor blackColor].CGColor;
if (![self.slidingViewController.underLeftViewController isKindOfClass:[MenuViewController class]]) {
self.slidingViewController.underLeftViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"MenuVC"];
}
[self.view addGestureRecognizer:self.slidingViewController.panGesture];
self.menuBtn = [UIButton buttonWithType:UIButtonTypeCustom];
_menuBtn.frame = CGRectMake(8, 80, 34, 24);
[_menuBtn setBackgroundImage:[UIImage imageNamed:#"menuButton.png"] forState:UIControlStateNormal];
[_menuBtn addTarget:self action:#selector(revealMenu:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.menuBtn];
NSLog(#"MainVC loaded");
}
- (IBAction)revealMenu:(id)sender
{
[self.slidingViewController anchorTopViewTo:ECRight];
}

Answer 1

You're better off not doing that...
This isn't app delegate responsibility
There are 3rd party implementations on github / CocoaControls which offer this and manage the navigation bar
It is much better to rework your current view hierarchy than to force a connection from the app delegate.
The responsibility of the app delegate is to respond to app level events (like foreground / background notifications). It might be involved in setting up the initial UI but other than that is should do basically nothing.