ios - 选项卡式应用程序不会显示登录 View

Question

我在 Xcode 4.3 中有一个标签栏应用程序，我试图在显示标签栏之前插入一个登录屏幕。如果presentModalViewController，应用程序运行正常有animated:YES但如果没有动画，则 View 不会显示。

@synthesize window = _window;

@synthesize tabBarController = _tabBarController;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
    UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];

    self.tabBarController = [[UITabBarController alloc] init];
    self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, nil];
    self.window.rootViewController = self.tabBarController;

    LogInViewController *logViewController = [[LogInViewController alloc] initWithNibName:@"LogInViewController" bundle:nil];
    [self.window addSubview:_tabBarController.view];

    [self.tabBarController presentModalViewController:logViewController animated:YES];
    //This wont work
    //[self.tabBarController presentModalViewController:logViewController animated:NO];

    [self.window makeKeyAndVisible];
    return YES;

}

-(void)loginDone{

    NSLog(@"back to the app delegate");
   [self.tabBarController dismissModalViewControllerAnimated:YES];


}

1. 这样做正确吗？
2. 为什么代码不能使用 animated:NO ？
3. 我也在输出中得到这个 Unbalanced calls to begin/end appearance transitions for <UITabBarController: 0x689d350> .

Answer 1

首先，在 View Controller 设置之前移动 [self.window makeKeyAndVisible];。

此外，您应该在首先可见的 View Controller 的 viewWillAppear: 方法中显示模态视图 Controller ，以确保您的应用 View 层次结构在显示您的登录之前已完全初始化屏幕。