通过App Delegate的UITabBarController检测何时按下tabBar项 [英] detect when a tabBar item is pressed via UITabBarController from App Delegate

问题描述

我知道这个问题已经问过几次了，但是当我在AppDelegate类中放置UITabBarController并且将viewControllers仅设置为

I know this question has been asked a few times, but I am still stuck on the case when I have my UITabBarController in my AppDelegate class and viewControllers are set there only as

self.tabBarController.viewControllers = 
     @[aboutUsNavController,myProfileNavController,
      projectsListNavController, feedsNavController,homeViewController];

现在我要执行的任务是在TabBar项目feedsNavController 不在 viewWillAppear中点击执行任务(因为它正在通过navigationController推动detailView).

Now what I want is to perform a task at the tap of TabBar item feedsNavController not in viewWillAppear (because it is pushing a detailView via navigationController ).

我已经在同一类中设置了委托以执行UITabBarController委托方法:

I have set delegate in the same class to perform a UITabBarController delegate method:

 AppDelegate *appDelegate = 
         (AppDelegate *)[[UIApplication sharedApplication] delegate];
appDelegate.tabBarController.delegate = self;

但是 -(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController仅在我切换TabBar项时起作用，但不是第一次?

But -(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController only works when I switch the TabBar Item, but not at the first time?

有什么方法可以代替UITabBarDelegate?

-(void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item

以便在按下tabBar item时获得参考?

in order to get the reference when tabBar item is pressed?

否则将不胜感激.

推荐答案

找出解决方法:

实际上，UITabBarControllerDelegate方法仅在加载该特定选项卡后才被调用.

Actually UITabBarControllerDelegate method only gets called once that particular tab it loaded.

因此，我第一次在viewDidLoad中执行了任务[self getFeedsFromServer];，然后在

Therefore, I performed task [self getFeedsFromServer]; in viewDidLoad (for first time), and then again in

-(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
    NSLog(@"Selected INDEX OF TAB-BAR ==> %i", tabBarController.selectedIndex);

    if (tabBarController.selectedIndex == 3) {
      [self getFeedsFromServer];
    }
}

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