How to create an action for a UITabBarItem?

Question

我已经创建了一个没有UITabBarController的UITabBar和UITabBarItems，现在我想知道如何在点击UITabBarItem时放置一个动作。我应该用什么方法对UITabBarItem采取行动？

Answer 1

You can't set an action on a UITabBarItem object directly. Instead, your view controller should implement the following UITabBarDelegate method:

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

This method is called when the user selects a tab (ie UITabBarItem ).

Answer 2

Are you using a UINavigationController? If so, from the active view controller subclass you get the navigationItem and add the buttons to it, eg:

- (void) viewWillAppear:(BOOL)animated;
{
    [super viewWillAppear: animated];
    UIBarButtonItem * leftButtonItem = [[[UIBarButtonItem alloc] initWithTitle: @"Don't Show Again" style: UIBarButtonItemStyleBordered target: self action: @selector(permanentlyCloseWelcomeView)] autorelease];
    [[self navigationItem] setLeftBarButtonItem: leftButtonItem];
}

Answer 3

Can you get away with using instances of UIToolbar and UIBarButtonItem instead? It could be more straightforward.

toolBar = [[UIToolbar alloc] init];
newPlayerItem = [[UIBarButtonItem alloc] initWithTitle:@"+"
                                    style:UIBarButtonItemStyleBordered
                                    target:self
                                    action:@selector(newPlayer:)];

NSArray *toolBarItemsArray = [[NSArray alloc] initWithObjects:newPlayerItem, nil];
[toolBar setItems:toolBarItemsArray];
[toolBarItemsArray release];

Answer 4

There is a better method than didSelectItem: for each TabBarItem you create an action:
[item1 setAction:@selector(pressItem1:)];
[item2 setAction:@selector(pressItem2:)];
[item3 setAction:@selector(pressItem3:)];
[item4 setAction:@selector(pressItem4:)];
and then you can use the new actions:

-(void)pressItem1:(UITabBarItem *) item1 {<br/>
    // Here comes your code which<br/>
    // occurs after pressing item1.<br/>
}

That works for me