Iphone TabBar应用程序，CoreData相关应用程序崩溃

在我的项目中，我使用一个tabBarController作为rootView控制器，然后在我的一个选项卡上，添加我现有的ToDoList应用程序。我遇到的问题是：如果我在AppDelegate中使用此代码：ToDoList将作为RootView加载。但我希望它只显示在适当的标签选择

- (void)applicationDidFinishLaunching:(UIApplication *)application {  
    //todoRootController.managedObjectContext = self.managedObjectContext;
    ToDoRootViewController *todoRootViewController = [[ToDoRootViewController alloc]initWithNibName:@"ToDoRootViewController" bundle:nil];
    NSManagedObjectContext *context = [self managedObjectContext];

    if (!context) {
        // Handle the error.
    }

    // Pass the managed object context to the view controller.
    todoRootViewController.managedObjectContext = context;
    UINavigationController *aNavigationController = [[UINavigationController alloc]                                                  
                                                     initWithRootViewController:todoRootViewController];
    self.navigationController = aNavigationController;

    [window addSubview:[navigationController view]];
    [window makeKeyAndVisible];
    [todoRootViewController release];

    [aNavigationController release];
}

I replace applicationdFinishLaunching：（UIApplication*）应用程序方法作为CoreDataReceipeis示例代码

- (void)applicationDidFinishLaunching:(UIApplication *)application {  
    todoRootController.managedObjectContext = self.managedObjectContext;

//////////////// same stuff
}

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但随后它给出了“NSInternalInconsistencyException”，原因：“+entityForName:找不到实体名称“任务”的NSManagedObjectModel

使用界面生成器设置在键入选项卡时将显示的选项卡视图控制器

如果必须以编程方式执行，则应查看TabBarController的文档

的

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默认情况下，在调用选项卡控制器时显示第一个选项卡。是否希望第一个选项卡的视图控制器仅在触摸时显示？我已在interface builder中将ToDoListViewController设置为相应的选项卡。但正如我所提到的，如果我使用第一个代码段，ToDoListViewController将加载为rootview。如果我使用第二个代码段，它会给出上述异常。我真的对这件事感到厌烦：（：(

- (void)applicationDidFinishLaunching:(UIApplication *)application { 

  tabBarController = [[UITabBarController alloc] init]; 

  MyViewController* vc1 = [[MyViewController alloc] init]; 

  MyOtherViewController* vc2 = [[MyOtherViewController alloc] init]; 

  NSArray* controllers = [NSArray arrayWithObjects:vc1, vc2, nil]; 

  tabBarController.viewControllers = controllers; 

  // Add the tab bar controller's current view as a subview of the window 
  [window addSubview:tabBarController.view];

}