UIViewController -viewDidLoad not being called

Question

Being new to Cocoa, I'm having a few issues with Interface Builder, UIViewController and friends.

I have a UIViewController subclass with a UIView defined in a xib, and with the controller's view outlet connected to the view. The xib's "file's owner" is set as myViewcontroller subclass.

In this one instance, the following code to load the controller/view (from the main view controller) doesn't work as expected:

if ( self.myViewController == nil )
{
    self.myViewController = [[MyViewController alloc]
        initWithNibName:@"MyViewController" bundle:nil];
}

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

In MyViewController's methods, I have placed breakpoints and log messages to see what is going on:

-(id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {

    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        NSLog(@"initWithNibName\n");
    }

    return self;
}

-(void)viewDidLoad {

    [super viewDidLoad];
    NSLog(@"viewDidLoad\n");
}

Expected result

Both -initWithNibName and -viewDidLoad methods are called, and myViewController's view is displayed.

Observed result

Only -initWithNibName is called, the view is not displayed.

Have I missed something? Can anyone recommend anything to check? (Particularly in the wondrously opaque Interface Builder tool).

Answer 1

SOLUTION FOUND!!!!!

Even something as innocuous as this makes the viewDidLoad method call happen.

Insert this right after alloc initWithNibName

viewController.view.hidden = NO; //calls viewDidLoad

Answer 2

Check your run log for errors. Almost certainly, the NIB is not loading, and there should be an error to that effect. The most likely cause for that is failure to put it in the bundle. Look in your "Copy Resources" build phase and make sure that the XIB is actually being copied. Build for the simulator, and go down into the build directory and make sure that the NIB is in the .app bundle.

Answer 3

Ok, I have a partial answer - maybe the gurus can explain some more. The problem is:

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

Looking more closely, in this case self.navigationController is nil - so the push message is going no-where.

Instead, if I send:

[self.view addSubview:self.myViewController.view];

Then the view appears and -viewDidLoad is called.

I'm not entirely sure why self.navigationController is not set in this instance - the only thing I can think of is that self is a subclass of UIViewController rather than UITableViewController (where the pushViewController code came from).

Also, silently allowing messages to go to nil seems like a bad idea, although these answers say otherwise. See also my question here.

Final edit:

Answers in comments below, I've realised the display function that I was actually after (given myViewController is modal) is:

[self presentModalViewController:myViewController animated:YES];

Thanks everyone for their helpful responses.