如何停止弹出到导航控制器的标签栏的第二次点击?

问题描述

我有一个基于标签栏的应用程序.所有选项卡都有一个导航控制器作为根.如果标签处于活动状态，用户再次点击标签，它会弹回导航控制器.

I have a tab bar based app. All tabs have a navigation controller as the root. If the user taps on the tab again if the tab is active, it pops back to the navigation controller.

我怎样才能阻止这种行为?

How can I stop this behavior?

所以实际上我有一个导航控制器 + 一个隐藏的 viewcontroller 可以做出一些决定 + 另一个视图控制器.对于原始问题中的误导性信息，我们深表歉意.我对所有选项卡(其中 3 个)使用隐藏的 viewcontroller，并将 1,2,3 单独的 viewcontrollers 放在每个选项卡上.

So in fact I have a navigation controller + a hidden viewcontroller that makes some decisions + another view controller. Sorry for the misleading information in the original question. I use the hidden viewcontroller for all the tabs, 3 of them, since I have the login screen on all 3 if the user is not logged in. If the user logs in, then I pop the login screen, and put the 1,2,3 individual viewcontrollers on each tab.

第一次点击:

 0 : class=Crossing: 0x645c8a0>  
 1 : class=FavoritesViewController: 0x64ac140>  
 shouldSelectViewController : UINavigationController  
 UINavigationController topclass:FavoritesViewController  
 myTabBarController.selectedViewController :UINavigationController  
 did disappear  
 didSelectViewController : UINavigationController  
 UINavigationController topclass:FavoritesViewController  

第二次点击:

 0 : class=Crossing: 0x645c8a0>  
 1 : class=FavoritesViewController: 0x64ac140>  
 shouldSelectViewController : UINavigationController  
 UINavigationController topclass:FavoritesViewController  
 myTabBarController.selectedViewController :UINavigationController  
 didSelectViewController : UINavigationController  
 UINavigationController topclass:Crossing  

推荐答案

@MarkGranoff 的做法是正确的，但方法是这样做:

@MarkGranoff was on the right track for doing this, but the way to do it is by doing something like this:

- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
{
    if ([tabBarController.viewControllers indexOfObject:viewController] == tabBarController.selectedIndex)
    {
        return NO;
    }
    else
    {
        return YES;
    }
}

或者用一种不那么冗长的方式:

or in a less verbose way:

- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
{
    return (viewController != tabBarController.selectedViewController);
}

如果您只想阻止某个选项卡的默认行为，那么您可以执行以下操作:

If you only want to block the default behaviour for a certain tab then you can do something like this:

- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
{
    NSUInteger indexOfNewViewController = [tabBarController.viewControllers indexOfObject:viewController];
    // Only the second tab shouldn't pop home 
    return ((indexOfNewViewController != 1) ||
            (indexOfNewViewController != tabBarController.selectedIndex));
}

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