如何识别标签栏项目？

Question

我想知道如何识别标签栏中的项目？

我有一个包含 NAvigationController 的 tabBarController，如下所示：

NSMutableArray *localViewControllersArray = [[NSMutableArray alloc] initWithCapacity:6];

每个 navigationController 都位于该数组内。

---

我使用以下方法管理每个选项卡栏项目中的操作：

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

我在这种方法中，即：

if (viewController == [self.tabBarController.viewControllers objectAtIndex:0])

像这样，我识别我单击的选项卡栏项目。

但问题是你可以在iphone屏幕中编辑Tabbar（因为数组中有6个viewControllers初始化tabbar）然后，我使用的方式是不正确的，因为我可以改变viewcontrollers的位置当我使用此编辑工具时在选项卡栏中。

谢谢

Answer 1

但是，我正在创建这样的 ViewController：（然后我无法进行#define，或输入不同的名称）

(UINavigationController *)createNavigationControllerWrappingViewControllerForDataSourceOfClass:(Class)datasourceClass {

id<VideosDataSource,UITableViewDataSource> dataSource = [[datasourceClass alloc] init];

// create the VideosTableViewController and set the datasource
VideosTableViewController *theViewController;   
theViewController = [[VideosTableViewController alloc] initWithDataSource:dataSource];

// create the navigation controller with the view controller
UINavigationController *theNavigationController;
theNavigationController = [[UINavigationController alloc] initWithRootViewController:theViewController];

// before we return we can release the dataSource (it is now managed by the ElementsTableViewController instance
[dataSource release];

// and we can release the viewController because it is managed by the navigation controller
[theViewController release];

return theNavigationController;

}

(void)setupPortraitUserInterface {

// a local navigation variable
// this is reused several times
UINavigationController *localNavigationController;

// Create a tabbar controller and an array to contain the view controllers
tabBarController = [[UITabBarController alloc] init];

// define a custom frame size for the entire tab bar controller that will be in the
// bottom half of the screen.
CGRect tabBarFrame;
tabBarFrame = CGRectMake(0, 0, 320, 460);
tabBarController.view.frame = tabBarFrame;

NSMutableArray *localViewControllersArray = [[NSMutableArray alloc] initWithCapacity:6];

// setup the 6 view controllers for the different data representations

// create the view controller and datasource for the VideosSortedBySuggestionsDataSource
// wrap it in a UINavigationController, and add that navigationController to the 
// viewControllersArray array

localNavigationController = [self createNavigationControllerWrappingViewControllerForDataSourceOfClass:[VideosSortedBySuggestionsDataSource class]];
[localViewControllersArray addObject:localNavigationController];

// the localNavigationController data is now retained by the application delegate
// so we can release the local variable
[localNavigationController release];


// repeat the process for the VideosSortedBySuggSearchDataSource
localNavigationController = [self createNavigationControllerWrappingViewControllerForDataSourceOfClass:[VideosSortedBySuggSearchDataSource class]];
[localViewControllersArray addObject:localNavigationController];

// the localNavigationController data is now retained by the application delegate
// so we can release the local variable
[localNavigationController release];            


// repeat the process for the VideosSortedByMostViewedDataSource
localNavigationController = [self createNavigationControllerWrappingViewControllerForDataSourceOfClass:[VideosSortedByMostViewedDataSource class]];
[localViewControllersArray addObject:localNavigationController];

// the localNavigationController data is now retained by the application delegate
// so we can release the local variable
[localNavigationController release];


// repeat the process for the VideosSortedByTopRatedDataSource
localNavigationController = [self createNavigationControllerWrappingViewControllerForDataSourceOfClass:[VideosSortedByTopRatedDataSource class]];
[localViewControllersArray addObject:localNavigationController];

// the localNavigationController data is now retained by the application delegate
// so we can release the local variable
[localNavigationController release];


// repeat the process for the VideosSortedBySearchDataSource
localNavigationController = [self createNavigationControllerWrappingViewControllerForDataSourceOfClass:[VideosSortedBySearchDataSource class]];
[localViewControllersArray addObject:localNavigationController];

// the localNavigationController data is now retained by the application delegate
// so we can release the local variable
[localNavigationController release];


// repeat the process for the VideosSortedBySearchDataSource
localNavigationController = [self createNavigationControllerWrappingViewControllerForDataSourceOfClass:[VideosSortedBySearchDataSource class]];
[localViewControllersArray addObject:localNavigationController];

// the localNavigationController data is now retained by the application delegate
// so we can release the local variable
[localNavigationController release];


// set the tab bar controller view controller array to the localViewControllersArray
tabBarController.viewControllers = localViewControllersArray;
// the localViewControllersArray data is now retained by the tabBarController
// so we can release this version
[localViewControllersArray release];
// set the window subview as the tab bar controller
[self.view addSubview:tabBarController.view];

}

Answer 2

您可以使用 UITabBarItem 的 tag 属性为每个 UITabBarItem 提供唯一的数字标识符，然后进行比较。

示例：

#define FirstViewController 1
#define SecondViewController 2
switch ([[viewController tabBarItem] tag]) {
  case FirstViewController:
    //the user selected your first view controller, no matter where it is on the tabbar
    break;
  case SecondViewController:
    break;
  ... etc
}

您可以记住指向每个 navigationControllers 的指针，并将它们与 viewController 参数进行比较。

示例：

//during your initial setup of the tabBarController:
UIViewController * firstViewController = //The view controller in the first tab
UIViewController * secondViewController = //The view controller in the second tab

...

if (viewController == firstViewController) {
  ...
} else if (viewController == secondViewController) {
  ...
}

您可以禁止在 UITabBarController 上进行编辑（将空数组或 nil 传递给控制器​​的 customizedViewControllers 属性）。

例子：

[myTabBarController setCustomizableViewControllers:nil];

Answer 3

为此，我从 Elements 演示开始。 在该演示中，每个数据源都有自己的覆盖名称。 然后，每当我需要为特定选项卡执行某些操作（因为它具有与其他选项卡不同的数据源）时，在我的主导航控制器中，我会执行以下操作：

if (datasource.name == @"Some name") {
    // something
}