When is viewDidLoad called?

Question

Is it safe to assume that an attribute, namely fetchedResultsController, of chatViewController, an instance of a subclass of UITableViewController, is always nil when viewDidLoad is called, assuming that it's set to nil in viewDidUnload? Phew!

If that's the case, then I see no immediate need to redefine the accessor function like in the Xcode example application CoreDataBooks. I'd rather just put all that code in viewDidLoad instead of in a separate function because that's the only place I'll use it.

score 4 · Accepted Answer · edited Oct 16 '18 at 20:41

viewDidLoad is called after your view is loaded. Whether or not fetchedResultsController is nil or not depends on how the viewController is initialized. For example, when creating the detailViewController, you could set its fetchedViewController before viewDidLoad is called:

RecipeDetailViewController *detailViewController = [[RecipeDetailViewController alloc] initWithStyle:UITableViewStyleGrouped];
detailViewController.fetchedResultsController = fetchedResultsController;

[self.navigationController pushViewController:detailViewController animated:animated];
[detailViewController release];

That said, then nil'ing fetchedResultsController in viewDidUnload would ensure that it's nil.

Cool. Thanks. I think your last sentence there has answered my question. That's good to know! :) — ma11hew28, Oct 16 '10 at 23:54

score 3 · Answer 2 · answered Jul 28 '15 at 10:59

ViewDidLoad Called in These Secnarion:-

1.when we push the view controller after creating it’s object by segue or by stoary board id.

2.it called more than one in the case of creating instance more time in application and push it again and again.for example:-if you implement like coaursal(that having required to additional controller during scrolling) like that it’s need so it can called multiple times viewDidLoad.

3.it called when all memory instance (uiviewcontroller and it’s subclass instantiated) that means when our view is ready to load in memory with the address.

4.Remember only child class controller object is created..parent class object never been instantiated during normal Secnarion.

score 2 · Answer 3 · answered Oct 16 '10 at 18:03

2

You have to assume that viewDidLoad can be called multiple times. If there is a memory warning sent, your view controller will unload the view from memory, and the next time it is needed viewDidLoad will be called.

answered Oct 16 '10 at 18:03

Aaron Saunders

33,180
5
60
80

2

Just to be clear, `viewDidLoad` won't be called multiple times consecutively. – Shaggy Frog Oct 16 '10 at 20:24
2

That makes sense. So, I can assume that if I set `fetchedResultsController` in `viewDidLoad` and `nil` it in `viewDidUnload`, then I won't be unnecessarily setting it again in `viewDidLoad`? In other words, `viewDidUnload` is always called before another call of `viewDidLoad`, correct? – ma11hew28 Oct 16 '10 at 23:53

score 1 · Answer 4 · answered Jul 13 '16 at 19:44

viewDidLoad is called only when view is instantiated for first time . If you're not recreating the view controller each time in your application, you'll only get it called once (and called again if you get a memory warning, and the view is nil'd out).

When is viewDidLoad called?

4 Answers4

Linked