Question

So I have an iPhone app. It has a simple structure, all based on a UINavigationController.

I have a storyboard that has one view, a segue to another view, etc. Now this other view has a UITextView that I do not want to edit on this screen – if the user taps this, I want it instead to fly over to a second screen which basically has the same text view, but this one is full-screen, and the user will edit the text on that screen before returning to the previous screen.

So I capture the textViewShouldBeginEditing method. I previously, in the storyboard editor, manually created a push segue from the previous view controller to this new view controller, and named it so that I can call it by it’s identity, which I do with:

- (BOOL)textViewShouldBeginEditing:(UITextView *)textView
{
    // This is called when the user clicks into the textView as if to edit it.

    // Instead of editing it, go to this other view here:
    [self performSegueWithIdentifier:@"editMemoSegue" sender:self];

    // Return NO, as I don't actually want to edit the text on this screen:
    return NO;
}

Seems reasonable. And it works. Sorta. It does in fact shoot me over to that other view. That other view’s events fire up, I set it’s text view to become first responder, I edit the text on that screen. Everyone’s happy.

Until I want to use the back button to return to the previous view.

Then I quickly find out – my navigation stack is foobared. Most of the time, I have, for some reason, TWO instances of my new editing controller on the stack, so the first time I hit the back button I get the same stuff over again. Then, oddly, occasionally, it will work as intended, and I will see my previous controller with only one back click.

I started reading the log, and I found this:

2012-12-09 09:41:03.463 APP[8368:c07] nested push animation can result in corrupted navigation bar
2012-12-09 09:41:03.818 APP[8368:c07] Finishing up a navigation transition in an unexpected state. Navigation Bar subview tree might get corrupted.
2012-12-09 09:41:03.819 APP[8368:c07] Unbalanced calls to begin/end appearance transitions for <SecondController: 0x83881d0>.

So obviously, I’m doing something incorrectly here. The question is, what? And how do I do what I want in the way that correctly appeases the tiki gods of the iPhone framework?

Answer 1

Check to see if the textViewShouldBeginEditing is being called twice. I’ve noticed that these kinds of delegate calls sometimes are.