Setting NavigationController.Viewcontrollers crashing (with custom transitions) - ios

Question

So this is my viewcontroller hierarchy:
-RootVC
-MapVC
-VC0
-VC1
-VC2
The app starts of by pushing #[Root, MapVC] to the view controller -- All good.
Then, my goal is to have the Map loaded (therefore, I don't want to pop the MapVC) while changing between the four main VCs (MapVC, VC0, VC1, VC2).
To do this, I use the following code:
-(void)presentViewController:(NSString*)viewControllerIdentifier{
UIViewController *vc = [self.storyboard instantiateViewControllerWithIdentifier:viewControllerIdentifier];
if (![[self.navigationController.viewControllers objectAtIndex:[[self.navigationController viewControllers] count]-1] isKindOfClass:[vc class]]){
NSMutableArray *viewControllers = [NSMutableArray arrayWithArray:[[self navigationController] viewControllers]];
if (![[viewControllers lastObject] isKindOfClass:[LLMapViewController class]]) {
[viewControllers removeLastObject];
}
[viewControllers addObject:vc];
[[self navigationController] setViewControllers:viewControllers animated:YES];
}
}
-(void)presentViewController0:(NSNotification*)notif{
[self presentViewController:[notif name]];
}
--
Method to present the map:
-(void)presentMapViewController:(NSNotification*)notif{
if (![[self.navigationController.viewControllers objectAtIndex:[[self.navigationController viewControllers] count]-1] isKindOfClass:[LLMapViewController class]]){
[self.navigationController popViewControllerAnimated:YES];
}
}
Well, it works well if I don't animate this transitions.
Also, when I do the following actions everything works well
App Launches:
->Root
->MapVC
ACTIONS:
0: Select VC0
->Root
->MapVC
->VC0
1: Select VC1 (Pops VC0 and pushes VC1, as you can see in the code above)
->Root
->MapVC
->VC1
2: Select MapVC (Pops VC1)
->Root
->MapVC
The problem is when I try to push another VC having the MapVC as main VC:
3: Select VC0
->Root
->Map
....
CRASH!
It doesn't show any consistent error.
Sometimes it doesn't show any error and sometimes it shows errors like these:
Example 1:
-[NSLayoutConstraint navigationController:animationControllerForOperation:fromViewController:toViewController:]:
Example 2:
-[UILabel navigationController:animationControllerForOperation:fromViewController:toViewController:]:
But it always highlights the part when I am setting the navigationcontroller's viewcontrollers .
MY PROBLEM: I have spent around 8 hours trying to fix this. I have no more ideas on how to debug this.
Can anyone please help me?
P.S. I am using custom transitions to push/pop the controllers.
Here's additional code:
-(id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC {
LLMenuAnimation *animationController = [[LLMenuAnimation alloc] initWithNavigationController:self.navigationController];
switch (operation) {
case UINavigationControllerOperationPush:
animationController.type = AnimationTypePush;
return animationController;
case UINavigationControllerOperationPop:
animationController.type = AnimationTypePop;
return animationController;
default:
NSLog(#"OTHER OPERATION");
return nil;
}
}
--
#pragma mark - Animated Transitioning
-(NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext {
return 0.2;
}
-(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext {
//Get references to the view hierarchy
UIView *containerView = [transitionContext containerView];
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
if (self.type == AnimationTypePush) {
//Add 'to' view to the hierarchy with 0.5 scale
toViewController.view.transform = CGAffineTransformMakeScale(0.5, 0.5);
[containerView insertSubview:toViewController.view aboveSubview:fromViewController.view];
//Scale the 'to' view to to its final position
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
// toViewController.view.frame = fromViewController.view.frame;
toViewController.view.transform = CGAffineTransformMakeScale(1.0, 1.0);
} completion:^(BOOL finished) {
[transitionContext completeTransition:YES];
}];
} else if (self.type == AnimationTypePop) {
//Add 'to' view to the hierarchy
[containerView insertSubview:toViewController.view belowSubview:fromViewController.view];
//Scale the 'from' view down
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
fromViewController.view.transform = CGAffineTransformMakeScale(0.5, 0.5);
} completion:^(BOOL finished) {
[transitionContext completeTransition:YES];
}];
}
}

Answer 1

I don't believe that you can use UINavigationController the way you are trying to do. If I have understood what you are trying to do, you are wanting to replace the navigationController's viewControllers property from underneath the navigation controller.
By the way, viewControllers property displayed is a copy. This is the way it is defined in the documentation:
#property(nonatomic, copy) NSArray *viewControllers
Your code:
NSMutableArray *viewControllers = [NSMutableArray arrayWithArray:[[self navigationController] viewControllers]];
if (![[viewControllers lastObject] isKindOfClass:[LLMapViewController class]]) {
[viewControllers removeLastObject];
}
[viewControllers addObject:vc];
[[self navigationController] setViewControllers:viewControllers animated:YES];
}
won't work the way you are expecting. You can push and pop view controllers onto the navigation controller. You can't replace the viewControllers the way you are trying to do.
By the way, the view controller hierarchy you drew in the first few lines of your question above is incomplete. Where is the navigation controller in the hierarchy?