切换根视图控制器答案

【问题标题】：Switching root view controller切换根视图控制器
【发布时间】：2016-06-29 01:11:46
【问题描述】：

我已经有一个带有 UINavigationController 的应用程序，但我想切换到 UITabBarController，问题是当我从一开始切换到 UItab 时它不起作用，所以我在委托方法中切换它但它没有也不行！ 应用委托中的所有代码。

self.navigationController = [[UINavigationController alloc] initWithRootViewController:[[UIViewController alloc] init]];
    self.tabBarController = [[UITabBarController alloc] init];


    if ([PFUser currentUser]) {
        // Present wall straight-away
        [self presentWallViewControllerAnimated:NO];
    } else {
        // Go to the welcome screen and have them log in or create an account.
        [self presentLoginViewController];
    }

    [PFAnalytics trackAppOpenedWithLaunchOptions:launchOptions];

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.rootViewController = self.navigationController;
    [self.window makeKeyAndVisible];

我要开启的委托方法：

- (void)presentWallViewControllerAnimated:(BOOL)animated {
    NSLog(@"Called:presentWallViewControllerAnimated ");
//    self.navigationController = nil;

    self.tabBarController = [[UITabBarController alloc] init];

    PAWWallViewController *wallViewController = [[PAWWallViewController alloc] initWithNibName:nil bundle:nil];
    wallViewController.delegate = self;


    // Set up the first View Controller
    UIViewController *vc1 = [[UIViewController alloc] init];
    vc1.view.backgroundColor = [UIColor orangeColor];
    vc1.tabBarItem.title = @"Orange";
    vc1.tabBarItem.image = [UIImage imageNamed:@"heart"];

    // Set up the second View Controller
    UIViewController *vc2 = [[UIViewController alloc] init];
    vc2.view.backgroundColor = [UIColor purpleColor];
    vc2.tabBarItem.title = @"Purple";
    vc2.tabBarItem.image = [UIImage imageNamed:@"star"];

    // Set up the Tab Bar Controller to have two tabs

    [self.tabBarController setViewControllers:@[ vc1, vc2]];

    self.window.rootViewController = self.tabBarController;

    [self.window makeKeyAndVisible];



//    [self.window addSubview:tabBarController.view];
//    [self.navigationController setViewControllers:@[ tabBarController ] animated:animated];
}

【问题讨论】：

标签： ios objective-c uiviewcontroller uinavigationcontroller uitabbarcontroller

【解决方案1】：

记得处理视图转换：

UIViewController *vc = // any vc that's initialized properly    
window.rootViewController = vc;

[UIView transitionWithView:window
                  duration:0.3  // 0.0 for immediate
                   options:UIViewAnimationOptionTransitionCrossDissolve // several enums to choose from here
                animations:nil
                completion:nil];

第一次之后你就不需要makeKeyAndVisible了。

【讨论】：

这也不起作用，我仍然看到带有 blackview 的导航栏

【解决方案2】：

你打电话给- (void)presentWallViewControllerAnimated:(BOOL)animated，但在didFinishLaunchingWithOptions结尾你打电话

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.window.rootViewController = self.navigationController;
[self.window makeKeyAndVisible];

所以标签栏永远不会起作用！

【讨论】：

那我该怎么办？
删除didFinishLaunchingWithOptions末尾的这些代码。并检查上面 if/else if ([PFUser currentUser]) 代码中的 rootViewController
但我需要导航控制器来显示登录或注册视图？
好的。我认为您可以将 rootViewController 设置为标签栏。如果您需要登录视图，您可以呈现不带动画的登录/注册视图。完成后，关闭它并返回标签栏。
我得到“试图在上显示，其视图不在窗口层次结构中！”