popToViewController not animating

Question

Man I must say if it wasn't for this site, I would have no hair and I would've probably jumped off of a bridge right now. OK! My problem:

I'm using storyboard with xcode 4.4. I have a 3 view controllers (well 5 really but the others i THINK are irrelevant). View controller A pushes to view controller B. View controller B has a segmented control on its nav bar with 2 segments and a back button.View contoller B loads with segment 1 selected. When user selects segment 0, view controller C is then instantiated. All well and good on the first push. You get pushed to B from A, and can then when you press back it pops to A. My problem is when I popToViewController to an array list containing view controller A, it pops, but it doesnt animate! I know what you're thinking, "Animate:YES dummy!" However, animated IS yes..HUH? Here's my code:

heres whats goin on in view controller B

-(IBAction)Previous:(id)sender{
[self.navigationController popViewControllerAnimated:YES];
}

- (IBAction)segmentSwitch:(id)sender;
{
if ([sender selectedSegmentIndex] == 0)
{
    MapViewController *controller = [self.storyboard           instantiateViewControllerWithIdentifier:@"Map"];
    [self.navigationController pushViewController:controller animated:NO];
}
else if ([sender selectedSegmentIndex] == 1) {
    ListViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"List"];
    [self.navigationController pushViewController:controller animated:NO];

}
}

heres view controller C

-(IBAction)Previous:(id)sender
{
NSInteger index = -1;

ReportAppDelegate *appDelegate =
(ReportAppDelegate *)[[UIApplication sharedApplication]delegate];
MainOrangeTestViewController *orangeViewController = [appDelegate orangeViewController];

orangeViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"Orange"];
NSArray* newVCarray = [[NSArray alloc] initWithObjects:orangeViewController, nil];
self.navigationController.viewControllers = newVCarray;

for(int i=0 ; i<[newVCarray count] ; i++)
{

    if([[newVCarray objectAtIndex:i] isKindOfClass:NSClassFromString(@"MainOrangeTestViewController")])
    {
        index = i;
    }
}
[self.navigationController popToViewController:[newVCarray objectAtIndex:index] animated:YES];



}
- (IBAction)segmentSwitch2:(id)sender; {
if ([sender selectedSegmentIndex] == 0)
{
    MapViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"Map"];
    [self.navigationController pushViewController:controller animated:NO];
}
else if ([sender selectedSegmentIndex] == 1)
{
   ListViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"List"];
    [self.navigationController pushViewController:controller animated:NO];
}
}

I know when you instantiate you are creating a new instance of that view controller as well as creating a new nav stack (or something like that). I'm thinking that might have something to do with it. Regardless, why on earth is it not animating the pop? I'm hoping to implement something in my current build, however if it requires a rebuild then so be it! Any help is greatly appreciated. I've definitely done my homework on this one however no solution.

Thanks to all in advance!

EDIT: I should add that the initial POP back to A from view controller B is animated. HOwever when you start to toggle the segmented controls AND when you toggle to view contrller C, going back to view controller A doesn't animate the pop. So initially when you load to B from A it pops back with successful animation. But after the toggle it pops back to A with no animation and the animated method is YES.

Answer 1

Are you just trying to push A->B->C and then pop back to A again, skipping B? If so, there's no need to modify the navigation controller's viewControllers property.

// in vcC.m ...

-(IBAction)Previous:(id)sender
{
    [self.navigationController popToRootViewControllerAnimated:YES];
}

Check out the different varieties of pop in the class reference. You can pop back one, or pop to the root, or pop to a particular VC that's in your history. The way to do that is to read the viewControllers stack (not write it), find the the VC you want to pop to, then use the popTo... method that's in your code.

But it sounds like popToRoot is what you'll need.

Answer 2

Still a little confused about your situation, but here's another tip: You can create history beforehand. Let's say you want to push from VC0 to VC2, and when popping, you want to pop from VC2 to either VC1 or to VC0. Totally doable:

// in VC0.m, animated push to VC2
// push to vc1 invisibly
[self.navigationController pushViewController:vc1 animated:NO];
// we've made history!  now push visibly to vc2
[self.navigationController pushViewController:vc2 animated:YES];

To choose where to pop back...

// in VC2.m
if (/* user needs a regular pop back to VC1 */) {
    [self.navigationController popViewControllerAnimated:YES];
} else // pop back two, to VC0
    NSArray *viewControllers = [self.navigationController viewControllers];

    // we're not assuming that vc0 is the root here, the top of the navigation stack
    // is at index=count-1.  self is at the top.  a regular pop is just below == count-2.
    // two pops is at count-3, and so on.
    NSInteger backBackIndex = viewControllers.count - 3;

    // in case we get here by some other pushing path, worst case pop is to the root
    backBackIndex = MAX(backBackIndex, 0);

    UIViewController *backBackVC = [viewControllers objectAtIndex:backBackIndex];
    [self.navigationController popToViewController:backBackVC animated:YES];
}