how to get the event that switch tab menu on iphon

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:?