viewDidAppear only gets called under certain circumstances? - ios

Question

I have this problem that has popped up out of the blue, I have checked all of the changes I have made in the past week and nothing seems to explain why my viewDidAppear only gets called when pushing to my VC under certain circumstances. These are the two ways I push to my VC.
-(void)receiveOnHostRoomConnectNotification:(NSNotification *)notificaiton
{
[[NSNotificationCenter defaultCenter]removeObserver:self name:kInitialize object:nil];
[[NSNotificationCenter defaultCenter]removeObserver:self name:kOnHostRoomConnect object:nil];
[[NSNotificationCenter defaultCenter]removeObserver:self name:kOnConnect object:nil];
dispatch_async(dispatch_get_main_queue(), ^{
[self performSegueWithIdentifier:#"toSetListRoomVC" sender:self];
});
}
Upon getting this 'onHost' notification I perform the segue. Pushing to the VC like this works EVERY TIME. viewDidAppear gets called in SetListRoomVC ever time.
However, when pushing upon this notification. the destinationVC's viewDidAppear will NEVER get fired.I havnt made any changes to these methods in a while and I doubt it has to do with them, but just giving explanation as to what is happening.
-(void)receiveInitializeNotification:(NSNotification *)notificaiton
{
[[NSNotificationCenter defaultCenter]removeObserver:self name:kInitialize object:nil];
[[NSNotificationCenter defaultCenter]removeObserver:self name:kOnHostRoomConnect object:nil];
[[NSNotificationCenter defaultCenter]removeObserver:self name:kOnConnect object:nil];
if (self.joinLabelSelected) {
self.roomCodeTextField.inputAccessoryView.hidden = YES;
[self.roomCodeTextField resignFirstResponder];
self.menuView.hidden = YES;
[self returnJoinLabel];
[UIView animateWithDuration:.25 animations:^{
self.roomCodeView.alpha = 0;
self.blurEffectView.alpha = 0;
} completion:^(BOOL finished) {
dispatch_async(dispatch_get_main_queue(), ^{
[self performSegueWithIdentifier:#"toSetListRoomVC" sender:self];
});
}];
}
}
I am also using a custom segue and a embedded navigation controller. This is how I have my custom segue set up.
#implementation CustomSegue
-(void) perform{
[[[self sourceViewController] navigationController] pushViewController:[self destinationViewController] animated:NO];
}
#end
All of my viewDidLoad,viewWillAppear,viewDidAppear implement [super view...:animated];
again, I haven't made any significant changes to any of my load,appear, methods in a while. I really don't understand why this is happening now.
Can anyone give an explanation for this? Also, every once in a while, maybe 10% of the time, the viewDidAppear method will get fired upon pushing the 'onHost' notification.
Thanks for any help. This boggling my mind.
EDIT: I rolled back to a commit from a few days ago and began rebuilding my project. So far viewDidAppear is working. I'll try to pinpoint what exactly is screwing everything up. Very strange though since most of what I have to rebuild is just Helper methods and minor UI updates.

Answer 1

These methods should be invoked every time and I've never seen them not being called.
Maybe you are using multiple subclasses inheriting from UIViewController and forgot to invoke super? In this case the super implementation is indeed not called:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
// do your stuff
}
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
// do your stuff
}
- (void)viewWillDisappear:(BOOL)animated {
// do your stuff
[super viewWillDisappear:animated];
}
- (void)viewDidDisappear:(BOOL)animated {
// do your stuff
[super viewDidDisappear:animated];
}
There might be some rare cases with interactive UINavigationController transitions, where a -viewWillDisappear: might get called, but no -viewDidDisappear:. E.g. if the user wipes from the left of the screen to navigate back and then cancels this action. This could result in a -viewWillDisappear:, but no corresponding -viewDidDisappear:.

Answer 2

Is your navigation controller ever behind anything? For example I think if you used presentViewController: to display a modal view controller on top of your navigation controller, and then pushed your VC onto the navigation controller, viewDidAppear wouldn't get called since iOS would think it was offscreen.
Have you tried putting NSLogs your navigation controller's viewWillAppear and viewWillDisappear methods to make sure that the navigation controller thinks it is visible when you push your new view controller?