Question

I have searched far and wide for an answer to this question and would be really grateful of some help. I have removed the rest of my application to keep the question simple.

My root view is simply a blank view with one button. It has been initialised with a UINaviagationController. All I want to do is to have the button push a new view onto the stack when pressed. At the moment, the button does nothing when pushed, here is my code.

#import <UIKit/UIKit.h>

@class ViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) ViewController *viewController;

@end


@implementation AppDelegate

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = self.viewController;

    UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:self.viewController];  

    [self.window addSubview:navigationController.view];  

    [self.window makeKeyAndVisible];  

    return YES;
}

Then in my first view controller:

#import "ViewController.h"

@implementation ViewController

-(IBAction)switchView:(id)sender
{
View2 *v2 = [[View2 alloc] initWithNibName:@"View2" bundle:nil];

[self.navigationController pushViewController:v2 animated:YES];

}

The -(IBAction) is configured properly, but still nothing, any ideas?

EDIT::

I have found a workaround to this.

It seems that when trying to access the NavigationController from the root view, using [self.navigationController…. ] will not send the message to the instance of navigationController (no idea why!).

I got it working by adding an ivar to ViewController of type UINavigationController, and then setting the ivar from AppDelegate after initializing ViewController, like such:

    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = self.viewController;


  //The UINavigationController declared int AppDelegate.h
    navController = [[UINavigationController alloc] initWithRootViewController:self.viewController];  

    [self.window addSubview:navController.view];

  //Set the ivar on ViewController (navCon) to the UINavigationController we just 
  //initialized 
    self.viewController.navCon = navController; 

Now when sending the message to the NavigationController in ViewController.m, I use the lines

View2 *v2 = [[View2 alloc] initWithNibName:@"View2" bundle:nil];

[navCon pushViewController:v2 animated:YES];

This does work, but I feel as though this is not the way it should be done, any thoughts?

Answer 1

Your code in application: didFinishLaunchingWithOptions: is pretty messed up. You must make the navigation controller your window’s rootViewController, not the nav controller’s root view controller. Then, the line [self.window addSubview:navigationController.view]; is superfluous and should be removed.