Pushing View Controller - viewDidAppear not called

Question

I have this piece of code to push a view controller:

        // Setup the animation
[self.navigationController pushViewController:self.productView animated:YES];

self.productView.imageURL = [product imageURL];

// Set the title of the view to the product's name
self.productView.title = [product name];

// Set the label text of all the labels in the view
[self.productView.caloriesL setText:[product calories]];
[self.productView.fatL setText:[product fat]];
[self.productView.saturatesL setText:[product saturates]];
[self.productView.sugarL setText:[product sugar]];
[self.productView.fibreL setText:[product fibre]];
[self.productView.saltL setText:[product salt]];

But the delegate method viewDidAppear does not get called when the productView appears. I looked up the problem on google and theres a lot of different solutions, none of which I could apply to my problem.. I had a similar problem in a previous solution but I got around it by manually calling viewDidApear in the viewDidLoad method. Unfortunately in this case I can't do that as viewDidLoad is called only once (on the first push). Does anyone know how to fix this?

Thanks,

Jack Nutkins

EDIT:

Here is the viewDidAppear method in the productView (and selector):

- (void)viewDidAppear:(BOOL)animated{
//Start animating the activity indicator
[indicator startAnimating];
//Perform this method in background
[self performSelectorInBackground:@selector(loadImage) withObject:nil];

}

- (void) loadImage {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    // Load the animals image into a NSData boject and then assign it to the UIImageView
    NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:imageURL]];
    UIImage *image = [[UIImage alloc] initWithData:imageData];
    self.imageView.image = image;

    //Stop animating the activity indicator
    [indicator stopAnimating];

    [pool drain]; //see comment below
}

Well is your self.productView a view or a view controller? Because the viewDidAppear is only called if your class is a view controller! — Wesley
Sorry yes, I should have mentioned that, its a view controller. — Jack Nutkins

Craig Otis Craig Otis · Accepted Answer · 2011-11-07T02:50:54

First: You definitely don't want to be calling any of the standard viewWillLoad, viewDidLoad, viewWillAppear, etc. methods manually. Let the OS do it for you.

Second: Can you show us how your viewDidAppear method is implemented in your self.productView instance? (Just a hunch, you're not expecting this method to be called on your navigation controller, right?) I just want to make sure your method signature is exactly correct. If it's not (due to a mispelling, improper args, etc.) then it definitely won't be called.

Third: I would move your pushViewController: call to after the rest of the code you provided. You don't want the view to be pushed on the screen (so the user can see it) and then have a bunch of on-screen values immediately change. Set your ivars and title property first, then push the view controller. This eliminates any weird flickering.

Pushing View Controller - viewDidAppear not called

2 Answers