UINavigationController Title Overlap - objective-c

Question

I am using a UINavigationController and pushing/popping UIViewControllers onto it. In some instances I am attempting to pop to the root view controller and then push a view controller after a short delay (0.1f).
My push code for the Message View Controller is as follows. My app fires two notifications. The first to select a tab and the second to push the correct view controller onto the stack of that tab.
//user taps a button and the app needs to switch tab and push the correct viewController
//onto the tab. I have tried setting pop == NO to avoid a 'double pop' but I still get
//overlapped titles
-(IBAction)messages:(id)sender {
NSDictionary* dictionary = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:[NSNumber numberWithInt:4], [NSNumber numberWithBool:YES] , nil] forKeys:[NSArray arrayWithObjects:#"tab",#"pop", nil]];
[[NSNotificationCenter defaultCenter] postNotificationName:kAutoSelectTab object:dictionary];
[[NSNotificationCenter defaultCenter] performSelector:#selector(postNotificationName:object:) withObject:kMessages afterDelay:0.1f];
}
//responds to the first notification
-(void)autoSelectTab:(NSNotification*)notification {
NSDictionary* dictionary = (NSDictionary*)[notification object];
int tab = [[dictionary objectForKey:#"tab"] intValue];
BOOL pop = [[dictionary objectForKey:#"pop"] boolValue];
[self.tabBarController setSelectedIndex:tab];
UIViewController* vc = [[self.tabBarController childViewControllers] objectAtIndex:tab];
PSLogDebug(#"Selecting tab:%#",[vc class]);
[self tabBarController:self.tabBarController didSelectViewController:vc];
if (pop == YES) {
if ([vc isKindOfClass:[UINavigationController class]]) {
[(UINavigationController*)vc popToRootViewControllerAnimated:YES];
}
}
}
//responds to the second notification
-(IBAction)messages:(id)sender {
[self.navigationController popToRootViewControllerAnimated:NO];
MessagesViewController* vc = [[MessagesViewController alloc] init];
[self.navigationController pushViewController:vc animated:YES];
[vc release];
}
Functionally the views appear to pop and push correctly BUT the titles do not pop and each new title is overlaid atop the old one.
I set the titles for each of the view controllers in viewDidLoad
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
self.navigationItem.title = #"More";
}
When I don't attempt the pop to root followed by the delay followed by the push - the titles and views behave as expected with no overlapping occurring.
Example Images from screenshots
I've had a good dig around stack overflow but I can't see any questions which describe the same issue as the one I am having.
Qn.1: Is there something fundamentally incorrect with the popToRoot, Delay, push View approach?
Qn.2: If anyone out there has seen this kind of behaviour before, how did you resolve it?

Answer 1

Increasing the delay from 0.1f to 0.5f fixed the problem
Change
[[NSNotificationCenter defaultCenter] performSelector:#selector(postNotificationName:object:) withObject:kMessages afterDelay:0.1f];
to
[[NSNotificationCenter defaultCenter] performSelector:#selector(postNotificationName:object:) withObject:kMessages afterDelay:0.5f];