iPhone UIViewController init method not being called

Question

I am very new to iPhone programming and am running into a little bit of weirdness. For the following class, the init method just never gets called -- I have an NSLog function which should tell me when init is executed. Here's the relevant code:

@interface MyViewController : UIViewController {
}
@end

@implementation MyViewController
- (id) init
{
    NSLog(@"init invoked");
    return self;
}
@end

Any ideas as to what I am doing wrong -- if anything? Hopefully I provided enough information.

Thanks.

Answer 1

If you are using a Storyboard, initWithCoder: will be called. Reference document says:

If your app uses a storyboard to define a view controller and its associated views, your app never initializes objects of that class directly. Instead, view controllers are either instantiated by the storyboard—either automatically by iOS when a segue is triggered or programmatically when your app calls the storyboard object’s instantiateViewControllerWithIdentifier: method. When instantiating a view controller from a storyboard, iOS initializes the new view controller by calling its initWithCoder: method instead. iOS automatically sets the nibName property to a nib file stored inside the storyboard.

The initWithCoder: method isn't part of the default template of a .m file, so you have to add yourself in your UIViewController subclass:

- (id)initWithCoder:(NSCoder *)aDecoder {

    self = [super initWithCoder:aDecoder];

    if (self) {
        // Custom initialization
        NSLog(@"Was called...");
    }

    return self;
}

There is no need to delete initWithNibName:bundle: from your code, but it won't be called anyway.

Answer 2

You are probably creating your view controller from a NIB file. So, instead of calling "init" message, this is the one creator message being called:

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Custom initialization
    }
    return self;
}

Try if that is the one being called. What Sean said is true. You could use those messages to accomplish similar things.

Good luck.

Answer 3

Is the view coming up? Use these methods for additional initialization:

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    //...
}

// Implement viewDidLoad to do additional setup after loading the view.
- (void)viewDidLoad {   
    [super viewDidLoad];
    //..
}

Answer 4

Refer 'designated initializer' in reference document too.