how to get the event that switch tab menu on iphone

问题

I'm trying to figure out how to catch the event that controls the switch tabs on the UITabBarController. How could I accomplish this?

回答1:

If you are using storyboard, do this

in didFinishLaunchingWithOptions

UITabBarController *tabBar = (UITabBarController *)self.window.rootViewController;
[tabBar setDelegate:self];

Also in AppDelegate, keep <UITabBarControllerDelegate>

And then

-(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
   //Write your code here
}

回答2:

Implement UITabBarControllerDelegate e.g. in your app delegate's applicationDidFinishLaunching

- (void)applicationDidFinishLaunching:(UIApplication *)application
{
    tabBarController.delegate = self;
    [window addSubview:tabBarController.view];
}

Then implement either:

- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController;

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController;

The first method is called before the view switch and gives you a chance to 'veto' the view switch by returning NO

The second method is called after the view switch has taken place

回答3:

Have a look at the following method in UITabBarControllerDelegate:

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController

Tells the delegate that the user selected an item in the tab bar.

回答4:

Is UITabBarControllerDelegate what you're looking for, particularly -tabBarController:didSelectViewController:?

回答5:

Better late than never. In case of swift 4 you can do it in the following way.

tabBarViewController.delegate = self

And implement UITabBarDelegate in your class. You will get the callback in

override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
  //Stuff to do
}

来源：https://stackoverflow.com/questions/2041982/how-to-get-the-event-that-switch-tab-menu-on-iphone