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.

reinaldoluckman · Answer 1 · 2014-05-02T15:36:28.177

28

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.

edited May 02 '14 at 15:36

answered Feb 20 '14 at 18:20

reinaldoluckman

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could you elaborate on this? Im using a viewController of subclass MyController which I have set the viewcontroller I made in storyboard to. However, in my .m file, I only see a initWithNibName method and no initWithCoder method. Am i supposed to delete initWithNibName and put in initWithCoder or am I doing something else wrong? – snapfish Mar 02 '14 at 00:47
There is no need to delete initWithNibName. Just add the initWithCoder (this method isn't in the default template for a .m file). I've changed my answer to denote this. – reinaldoluckman Mar 03 '14 at 12:29
1

Thanks for accepting my edit, no idea why it was rejected or what they think self is going to be without the [super init] Grrr. Cheers :) – B_o_b May 03 '14 at 10:06
I don't know why too. Thanks for pointing that. I really forgot. :) – reinaldoluckman May 04 '14 at 03:34

score 23 · Answer 2 · answered Apr 21 '09 at 11:51

23

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.

answered Apr 21 '09 at 11:51

Pablo Santa Cruz

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Right after I posted my comment above, I realized why init wasn't being called... :P – farhany Apr 21 '09 at 23:19
The designated initializer. Override if you create the controller **programmatically** and want to perform customization that is not appropriate for viewDidLoad. – Apr 21 '11 at 10:46

score 3 · Accepted Answer · answered Apr 21 '09 at 11:48

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];
    //..
}

answered Apr 21 '09 at 11:48

Sean

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Thanks! That worked. Though it leaves a little sour taste in my mouth to see some inconsistencies in Obj-C on iPhone. Oh well. – farhany Apr 21 '09 at 11:53

score 2 · Answer 4 · answered Jan 24 '10 at 08:23

2

Refer 'designated initializer' in reference document too.

answered Jan 24 '10 at 08:23

eonil

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score 2 · Answer 5 · answered Sep 08 '10 at 22:14

2

But, a UI component has sometimes severals init* methods, do we need to override all these methods in order to do some init. stuff?

answered Sep 08 '10 at 22:14

eBuildy

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Seems like you only have to override the "designated initializer". The only way to find out which init* method this is is via the documentation. – Nestor Apr 07 '11 at 04:37

iPhone UIViewController init method not being called

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