我遇到了同样的问题。
我能够想出一个非常有效的解决方法。我已经把它推到了 Github 上：https://github.com/jfahrenkrug/UITabBarControllerMoreBugWorkaround
欢迎任何改进。
该错误的发生是因为您的 UINavigationController 的堆栈已从中删除并放入私有 UIMoreNavigationController。但是在旋转回常规宽度时，该堆栈没有正确放回其原始 UINavigationViewController。
解决方案是继承 UITabBarController 并将其 willTransitionToTraitCollection:withTransitionCoordinator: 替换为这个：
- (void)willTransitionToTraitCollection:(UITraitCollection *)newCollection withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
{
//#define MORE_TAB_DEBUG 1
#ifdef MORE_TAB_DEBUG
#define MoreTabDLog(fmt, ...) NSLog((@"[More Tab Debug] " fmt), ##__VA_ARGS__);
#else
#define MoreTabDLog(...)
#endif
MoreTabDLog(@"-- before willTransitionToTraitCollection");
/*
There is a bug when going in and out of the compact size class when a tab bar
controller has more than 5 tabs. See http://www.openradar.me/25393521
It comes down to this: When you have more than 5 tabs and a view controller on a tab
beyond the 4th tab is a UINavigationController, you have a problem.
When you are on this tab in compact and push one or more VCs onto the stack and then
change back to regular width, only the top most view controller will be added back onto the
stack.
This happens because the stack of your UINavigationController is taken out of that NavVC and put
into the private UIMoreNavigationController. But upon rotating back to regular, that stack is not
correctly put back into your own NavVC.
We have 3 cases we have to handle:
1) We are on the "More" tab in compact and are looking at the UIMoreListController and then change to
regular size.
2) While in compact width, we are on a tab greater than the 4th and are changing to regular width.
3) While in regular width, we are on a tab greater than the 4th and are changing to compact width.
*/
if ((self.traitCollection.horizontalSizeClass != newCollection.horizontalSizeClass) ||
(self.traitCollection.verticalSizeClass != newCollection.verticalSizeClass))
{
/*
Case 1: We are on the "More" tab in compact and are looking at the UIMoreListController and then change to regular size.
*/
if ([self.selectedViewController isKindOfClass:[UINavigationController class]] && [NSStringFromClass([self.selectedViewController class]) hasPrefix:@"UIMore"]) {
// We are on the root of the MoreViewController in compact, going into regular.
// That means we have to pop all the viewControllers in the MoreViewController to root
#ifdef MORE_TAB_DEBUG
UINavigationController *moreNavigationController = (UINavigationController *)self.selectedViewController;
UIViewController *moreRootViewController = [moreNavigationController topViewController];
MoreTabDLog(@"-- going OUT of compact while on UIMoreList");
MoreTabDLog(@"moreRootViewController: %@", moreRootViewController);
#endif
for (NSInteger overflowVCIndex = 4; overflowVCIndex < [self.viewControllers count]; overflowVCIndex++) {
if ([self.viewControllers[overflowVCIndex] isKindOfClass:[UINavigationController class]]) {
UINavigationController *navigationController = (UINavigationController *)self.viewControllers[overflowVCIndex];
MoreTabDLog(@"popping %@ to root", navigationController);
[navigationController popToRootViewControllerAnimated:NO];
}
}
} else {
BOOL isPotentiallyInOverflow = [self.viewControllers indexOfObject:self.selectedViewController] >= 4;
MoreTabDLog(@"isPotentiallyInOverflow: %i", isPotentiallyInOverflow);
if (isPotentiallyInOverflow && [self.selectedViewController isKindOfClass:[UINavigationController class]]) {
UINavigationController *selectedNavController = (UINavigationController *)self.selectedViewController;
NSArray<UIViewController *> *selectedNavControllerStack = [selectedNavController viewControllers];
MoreTabDLog(@"Selected Nav: %@, selectedNavStack: %@", selectedNavController, selectedNavControllerStack);
UIViewController *lastChildVCOfTabBar = [[self childViewControllers] lastObject];
if ([lastChildVCOfTabBar isKindOfClass:[UINavigationController class]] && [NSStringFromClass([lastChildVCOfTabBar class]) hasPrefix:@"UIMore"]) {
/*
Case 2: While in compact width, we are on a tab greater than the 4th and are changing to regular width.
We are going OUT of compact
*/
UINavigationController *moreNavigationController = (UINavigationController *)lastChildVCOfTabBar;
NSArray *moreNavigationControllerStack = [moreNavigationController viewControllers];
MoreTabDLog(@"--- going OUT of compact");
MoreTabDLog(@"moreNav: %@, moreNavStack: %@, targetNavStack: %@", moreNavigationController, moreNavigationControllerStack, selectedNavControllerStack);
if ([moreNavigationControllerStack count] > 1) {
NSArray *fixedTargetStack = [moreNavigationControllerStack subarrayWithRange:NSMakeRange(1, moreNavigationControllerStack.count - 1)];
MoreTabDLog(@"fixedTargetStack: %@", fixedTargetStack);
dispatch_async(dispatch_get_main_queue(), ^{
NSArray *correctVCList = [NSArray arrayWithArray:self.viewControllers];
[selectedNavController willMoveToParentViewController:self];
[selectedNavController setViewControllers:fixedTargetStack animated:NO];
// We need to do this because without it, the selectedNavController doesn't
// have a parentViewController anymore.
[self addChildViewController:selectedNavController];
// We need to do this because otherwise the previous call will cause the given
// Tab to show up twice in the UIMoreListController.
[self setViewControllers:correctVCList];
});
} else {
MoreTabDLog(@"popping to root");
dispatch_async(dispatch_get_main_queue(), ^{
[selectedNavController popToRootViewControllerAnimated:NO];
});
}
} else {
/*
Case 3: While in regular width, we are on a tab greater than the 4th and are changing to compact width.
We are going INTO compact
*/
MoreTabDLog(@"-- going INTO compact");
if ([selectedNavControllerStack count] > 0) {
[coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> _Nonnull context) {
// no op
} completion:^(id<UIViewControllerTransitionCoordinatorContext> _Nonnull context) {
UIViewController *parentViewControllerOfTopVC = [[selectedNavControllerStack lastObject] parentViewController];
MoreTabDLog(@"parentViewControllerOfTopVC: %@", parentViewControllerOfTopVC);
if ([parentViewControllerOfTopVC isKindOfClass:[UINavigationController class]] && [NSStringFromClass([parentViewControllerOfTopVC class]) hasPrefix:@"UIMore"]) {
UINavigationController *moreNavigationController = (UINavigationController *)parentViewControllerOfTopVC;
NSArray *moreNavigationControllerStack = [moreNavigationController viewControllers];
BOOL isOriginalRootVCInMoreStack = [moreNavigationControllerStack containsObject:[selectedNavControllerStack firstObject]];
MoreTabDLog(@"moreNav: %@, moreNavStack: %@, isOriginalRootVCInMoreStack: %i", moreNavigationController, moreNavigationControllerStack, isOriginalRootVCInMoreStack);
if (!isOriginalRootVCInMoreStack) {
NSArray *fixedMoreStack = [@[moreNavigationControllerStack[0]] arrayByAddingObjectsFromArray:selectedNavControllerStack];
MoreTabDLog(@"fixedMoreStack: %@", fixedMoreStack);
[selectedNavController setViewControllers:selectedNavControllerStack animated:NO];
dispatch_async(dispatch_get_main_queue(), ^{
[moreNavigationController setViewControllers:fixedMoreStack animated:NO];
});
}
}
}];
}
}
}
}
}
[super willTransitionToTraitCollection:newCollection withTransitionCoordinator:coordinator];
MoreTabDLog(@"-- after willTransitionToTraitCollection");
}
享受吧！
约翰内斯