Sometimes willHideViewController from UISplitViewControllerDelegate is not called

问题

I have a problem. My app is a tab bar controller and its first view controller is a split view controller. This seems to be not ok for Apple because documents say a split voew controller must be the root, so perhaps that is the reason of my problems.

The problem is that sometimes, willHideViewController from UISplitViewControllerDelegate is not called, so, for this reason, the upper/left button sometimes is not created, which is anoying. I realised, to reproduce this error, try several times this: -Landscape mode. -Select a tab different to split view controller tap. -Move the iPad to portrait in that tab. -Go to the split view controller tab, and sometimes, willHideViewController is not called so you will not see the upper button. However if I rotate my iPad to landscape and after that to portrait, it's fixed.

I tried to force manually several rotations to work around this problem, but no luck. I still have to try any split view controller clone class from github or similar. Do you have idea what's going on or any work around?

Here I show you two examples working properly.

Thanks a lot for your help.

回答1:

Where do you set the splitViewControllers delegate? Perhaps you can set the delegate when you load the tab. It sounds like you set it only when you have rotated once?

Otherwise, see this example

Here they have the TableViewController be the delegate of the splitviewcontroller. Perhaps you could do the same with the TabBarController?

回答2:

I've concluded that this can't be done in any way that I consider 'sufficiently' legitimate. It's possible to get frustratingly close, but the issue of having the willShow..., willHide disseminated to the split view controllers under each tab remains.

The solution that seems most likely to work is,

https://github.com/grgcombs/IntelligentSplitViewController/blob/master/IntelligentSplitViewController.m

Though this code is undoubtedly clever, it's a bit too 'side door' for me. I suspect (but don't know) that just invoking the delegate methods is not sufficient. Surely the UISplitViewController itself needs to change it's internal state as well as calling the delegate methods? This method 'just' invokes the delegate methods when there's an orientation change.

So... I've decided on a more legitimate solution, which is to use the new method introduced in iOS 5.

- (BOOL) splitViewController:(UISplitViewController *)svc
             shouldHideViewController:(UIViewController *)vc
             inOrientation:(UIInterfaceOrientation)orientation
{
     return NO;
}

So, the master menu is never hidden, and therefore the problem of managing the popover doesn't arise.

Of course, this is still not totally 'legit' as it still includes UISplitViewControllers that are not at the top level (the UITabViewController is at the top level, and the split views are on each tab)

Good luck with whichever solution you choose.

I'll update this reply when I've confirmed Apple will approve an app using this solution.

来源：https://stackoverflow.com/questions/8874149/sometimes-willhideviewcontroller-from-uisplitviewcontrollerdelegate-is-not-calle