对UITabBarController的开始/结束外观转换的不平衡调用

Question

我有一个UITabBarController,在初始运行时,我想覆盖登录视图控制器但收到错误.

对<UITabBarController:0x863ae00>的开始/结束外观转换的不平衡调用.

下面是代码.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

    // Override point for customization after application launch.

    UIViewController *lessonVC = [[[LessonViewController alloc] initWithNibName:@"LessonViewController" bundle:nil] autorelease];

    UIViewController *programVC = [[[ProgramViewController alloc] initWithNibName:@"ProgramViewController" bundle:nil] autorelease];

    UIViewController *flashcardVC = [[[FlashCardViewController alloc] initWithNibName:@"FlashCardViewController" bundle:nil] autorelease];

    UIViewController *moreVC = [[[MoreViewController alloc] initWithNibName:@"MoreViewController" bundle:nil] autorelease];

    UINavigationController *lessonNVC = [[[UINavigationController alloc] initWithRootViewController:lessonVC] autorelease];

    UINavigationController *programNVC = [[[UINavigationController alloc] initWithRootViewController:programVC] autorelease];

    UINavigationController *flashcardNVC = [[[UINavigationController alloc] initWithRootViewController:flashcardVC] autorelease];

    UINavigationController *moreNVC = [[[UINavigationController alloc] initWithRootViewController:moreVC] autorelease];

    self.tabBarController = [[[UITabBarController alloc] init/*WithNibName:nil bundle:nil*/] autorelease];
    self.tabBarController.viewControllers = [NSArray arrayWithObjects:lessonNVC, programNVC, flashcardNVC, moreNVC, nil];
    self.tabBarController.selectedIndex = 0;
    self.window.rootViewController = self.tabBarController;

    [self.window makeKeyAndVisible];

    if (![[ZYHttpRequest sharedRequest] userID]) 
    {
        // should register or login firstly
        LoginViewController *loginVC = [[LoginViewController alloc] initWithNibName:@"LoginViewController"
                                                                             bundle:nil];
        loginVC.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
        [self.tabBarController presentModalViewController:loginVC animated:YES];
        ZY_SAFE_RELEASE(loginVC);
    }

    return YES;
}

谁可以帮助我？提前致谢!

Answer 1

您需要等待呈现模态视图控制器,直到下一个运行循环.我最终使用一个块(使事情更简单)来安排下一个运行循环的演示:

更新:
正如Mark Amery在下面提到的,只是一个简单的dispatch_async工作,不需要计时器:

dispatch_async(dispatch_get_main_queue(), ^(void){     
  [self.container presentModalViewController:nc animated:YES]; 
});

/* Present next run loop. Prevents "unbalanced VC display" warnings. */
double delayInSeconds = 0.1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
    [self.container presentModalViewController:nc animated:YES];
});

Answer 2

我怀疑问题是你在presentModalViewController:标签栏完成加载之前试图调用.尝试将最终逻辑移动到下一个事件循环:

  [self.window makeKeyAndVisible];
  [self performSelector:(handleLogin) withObject:nil afterDelay:0];
}

- (void)handleLogin
{
  if (![[ZYHttpRequest sharedRequest] userID]) 
    {
        // should register or login firstly
        LoginViewController *loginVC = [[LoginViewController alloc] initWithNibName:@"LoginViewController"
                                                                             bundle:nil];
        loginVC.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
        [self.tabBarController presentModalViewController:loginVC animated:YES];
        ZY_SAFE_RELEASE(loginVC);
    }
}

Answer 3

[self.tabBarController presentModalViewController:loginVC animated:**NO**];