popToRootViewController when another tab is selected

问题:

Context:

I am using TabViewController and NavigationController at the same time. The two tabs are RECENT and POPULAR and they show a list of posts. Imagine you're inside RECENT tab and click a post, and you go into a postsShow view. So you're one deeper in a navigation stack. When you go to POPULAR tab and come back to RECENT tab, you are still seeing the post you clicked before. But I want to show a list of posts instead.

What I am trying:

I am setting PostsShowViewController a TabBarControllerDelegate and when a tab item is selected, I am trying to pop to its root view controller. Then, when the user comes back, he will see the rootViewController, which is the list of posts instead of PostsShow view.

Code:

viewDidAppear self.tabBarController.delegate = self;

viewDidDisappear self.tabBarController.delegate = nil;

header UITabBarControllerDelegate

- (BOOL) tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController {     [self.navigationController popToRootViewControllerAnimated:NO];     return YES; } 

How it doesn't work:

1. Go to recent tab
2. Click a post to go to PostsShow view
3. Go to popular tab
4. Go back to recent tab (I am expecting to see a list of posts instead of PostsShow view)
5. Error! EXC_BAD_ACCESS

EDIT: Following what the answers suggest doing, I get a slightly better behavior but still end up with an error.

Code

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController{     UINavigationController *navigation = (UINavigationController*) viewController;     [navigation popToRootViewControllerAnimated:NO]; } 

1. go to recent tab
2. click post to go to PostsShowview
3. go to popular tab
4. go back to recent tab
5. I see a list of posts (no error!)
6. go back to popular tab : ERR_BAD_ACCESS!

EDIT: this is my storyboard

EDIT2:

full stack track:

* thread #1: tid = 0x4a37c, 0x0000000197bb7bd0 libobjc.A.dylib`objc_msgSend + 16, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x10)     frame #0: 0x0000000197bb7bd0 libobjc.A.dylib`objc_msgSend + 16     frame #1: 0x000000018ab52078 UIKit`-[UITabBarController _tabBarItemClicked:] + 104     frame #2: 0x000000018a9891ec UIKit`-[UIApplication sendAction:to:from:forEvent:] + 96     frame #3: 0x000000018ab51fb4 UIKit`-[UITabBar _sendAction:withEvent:] + 468     frame #4: 0x000000018a9891ec UIKit`-[UIApplication sendAction:to:from:forEvent:] + 96     frame #5: 0x000000018a9722c8 UIKit`-[UIControl _sendActionsForEvents:withEvent:] + 612     frame #6: 0x000000018ab51bec UIKit`-[UITabBar(Static) _buttonUp:] + 128     frame #7: 0x000000018a9891ec UIKit`-[UIApplication sendAction:to:from:forEvent:] + 96     frame #8: 0x000000018a9722c8 UIKit`-[UIControl _sendActionsForEvents:withEvent:] + 612     frame #9: 0x000000018a988b88 UIKit`-[UIControl touchesEnded:withEvent:] + 592     frame #10: 0x000000018a947da8 UIKit`_UIGestureRecognizerUpdate + 8536     frame #11: 0x0000000185e8fff0 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 32     frame #12: 0x0000000185e8cf7c CoreFoundation`__CFRunLoopDoObservers + 360     frame #13: 0x0000000185e8d35c CoreFoundation`__CFRunLoopRun + 836     frame #14: 0x0000000185db8f74 CoreFoundation`CFRunLoopRunSpecific + 396     frame #15: 0x000000018f8136fc GraphicsServices`GSEventRunModal + 168     frame #16: 0x000000018a9bad94 UIKit`UIApplicationMain + 1488   * frame #17: 0x0000000100023ff4 toaster-objc`main(argc=1, argv=0x000000016fdeba50) + 124 at main.m:14     frame #18: 0x000000019824ea08 libdyld.dylib`start + 4 

回答1:

Here is how I did it in swift:

func tabBarController(tabBarController: UITabBarController, didSelectViewController viewController: UIViewController) {      self.tabBarSelectedIndex = tabBarController.selectedIndex     var navigation = viewController as! UINavigationController     navigation.popToRootViewControllerAnimated(false)     // rest of the logic } 

Similar in objective-C:

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {     self.tabBarSelectedIndex = tabBarController.selectedIndex;     UINavigationController *navigation = (UINavigationController*) viewController;     [navigation popToRootViewControllerAnimated:NO]; } 

Notice that I used didSelectViewController method for UITabBarController.

You can check it here:

回答2:

Try This:

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController{  if ([viewController isKindOfClass:[UINavigationController class]]) {     UINavigationController *navController = (UINavigationController *)viewController;      [navController popToRootViewControllerAnimated:NO];  } } 

回答3:

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {     if ([viewController isKindOfClass:[UINavigationController class]]) {         [(UINavigationController *)viewController popToRootViewControllerAnimated:YES];     } } 

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