Question

It appears that ViewDidLoad() is sent to a ViewController only after its View is physically displayed (i.e. via NavigationController pushViewController), and not immediately after initWithNibName(). Is this a behavior I can rely on? I would like to get the chance to set the member variables of my view so that all the members are valid by the time ViewDidLoad() is invoked.

Answer 1

You can set up member variables and other such things in initWithNibName:bundle:.

- (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle {
    if (self = [super initWithNibName:nibName bundle:nibBundle]) {
        // set up ivars and other stuff here.
        someIvar = someValue;
    }
    return self;
}

You are correct that viewDidLoad: is only sent when the view is physically displayed, i.e when it is added to some visible view (which may sometimes be never if the user does not reach that view). So it’s useful to split the functionality and think about what you can do at init time and what happens at view load time.

As Marcelo Cantos notes in the comment, viewDidLoad: is generally a fine place to do all sorts of setup work, using the concept of “lazy loading,” so that you defer the setup until as late time as possible.