objective c - 呈现视图控制器时出错

Question

我试图从两个不同的角度展示一个视图控制器，我将在一秒钟内解释：

1. 我放置在标签栏中的自定义按钮
2. 来自UIBarButtonItem

两种方式都会给我以下错误：

Warning: Attempt to present <UINavigationController: 0x14e627c10> on <UINavigationController: 0x14e6211e0> whose view is not in the window hierarchy!

我会把“很少”的代码行放在可能相关的位置：

标签栏的初始化：

- (void)presentTabBarController {
    UIStoryboard *tabbarStoryboard = [UIStoryboard storyboardWithName:@"MainTabBarViews" bundle:nil];

    self.feedViewController = [tabbarStoryboard instantiateViewControllerWithIdentifier:@"GSFeedViewController"];
    self.exploreViewController = [tabbarStoryboard instantiateViewControllerWithIdentifier:@"GSExploreViewController"];
    self.createGroupViewController = [tabbarStoryboard instantiateViewControllerWithIdentifier:@"GSCreateGroupViewController"];
    self.messagingViewController = [tabbarStoryboard instantiateViewControllerWithIdentifier:@"GSMessagingViewController"];
    self.profileViewController = [tabbarStoryboard instantiateViewControllerWithIdentifier:@"GSProfileViewController"];

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

    UINavigationController *feedNavigationController = [[UINavigationController alloc]initWithRootViewController:self.feedViewController];    
    UINavigationController *exploreNavigationController = [[UINavigationController alloc]initWithRootViewController:self.exploreViewController];
    UINavigationController *createGroupNavigationController = [[UINavigationController alloc]initWithRootViewController:self.createGroupViewController];
    UINavigationController *messagingNavigationController = [[UINavigationController alloc]initWithRootViewController:self.messagingViewController];
    UINavigationController *profileNavigationController = [[UINavigationController alloc]initWithRootViewController:self.profileViewController];

    UITabBarItem *feedItem = [[UITabBarItem alloc]init];
    feedItem.image = [UIImage imageNamed:@"tabbar-feed-icon1"];
    feedItem.title = @"Timeline";
    [feedNavigationController setTabBarItem:feedItem];

    UITabBarItem *exploreItem = [[UITabBarItem alloc]init];
    exploreItem.image = [UIImage imageNamed:@"tabbar-explore-icon1"];
    exploreItem.title = @"Explore";
    [exploreNavigationController setTabBarItem:exploreItem];

    UITabBarItem *messageItem = [[UITabBarItem alloc]init];
    messageItem.image = [UIImage imageNamed:@"tabbar-message-icon1"];
    messageItem.title = @"Messages";
    [messagingNavigationController setTabBarItem:messageItem];

    UITabBarItem *profileItem = [[UITabBarItem alloc]init];
    profileItem.image = [UIImage imageNamed:@"tabbar-profile-icon1"];
    profileItem.title = @"Profile";
    [profileNavigationController setTabBarItem:profileItem];


    self.tabBarController.viewControllers = @[feedNavigationController, exploreNavigationController, createGroupNavigationController, messagingNavigationController, profileNavigationController];
    self.tabBarController.tabBar.translucent = YES;

    UIButton* button = [UIButton buttonWithType:UIButtonTypeCustom];
    UIImage *buttonImage = [UIImage imageNamed:@"tabbar-group-icon"];
    UIImage *highlightImage = [UIImage imageNamed:@"tabbar-group-selected-icon"];
    button.autoresizingMask = UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleBottomMargin | UIViewAutoresizingFlexibleTopMargin;
    button.frame = CGRectMake(0.0, 0.0, buttonImage.size.width -0, buttonImage.size.height -1);
    button.clipsToBounds = YES;
    button.userInteractionEnabled = YES;
    button.layer.borderColor = [[UIColor blackColor]CGColor];
    button.layer.borderWidth = 0.5f;
    //button.layer.cornerRadius = buttonImage.size.width / 6;
    [button setBackgroundImage:buttonImage forState:UIControlStateNormal];
    [button setBackgroundImage:highlightImage forState:UIControlStateHighlighted];
    [button addTarget:self action:@selector(popCreateGroupModel) forControlEvents:UIControlEventTouchUpInside];


    CGFloat heightDifference = buttonImage.size.height - self.tabBarController.tabBar.frame.size.height;
    if (heightDifference < 0)
        button.center = self.tabBarController.tabBar.center;
    else
    {
        CGPoint center = self.tabBarController.tabBar.center;
        center.y = center.y - heightDifference/2.0;
        button.center = center;
    }

    [self.tabBarController.view addSubview:button];

    self.navController = [[UINavigationController alloc]init];
    [self.navController setViewControllers:@[self.tabBarController] animated:NO];
}  

弹出呈现ViewController

-(void)popCreateGroupModel
{
    UINavigationController *nav = [[UINavigationController alloc]
                                   initWithRootViewController:self.createGroupViewController];
    [[self.tabBarController navigationController] presentViewController:nav animated:YES completion:nil];
}

这是第一种方式，第二种方式就是我说出一个呈现VC的按钮。

- (IBAction)openNewGroupModal:(id)sender {
    UINavigationController *nav = [[UINavigationController alloc]
                                   initWithRootViewController:[GSAppDelegate sharedDelegate].createGroupViewController ];
    [[[[GSAppDelegate sharedDelegate] tabBarController] navigationController] presentViewController:nav animated:YES completion:nil];
}

最后但并非最不重要：我的AppDelegate的属性

@interface GSAppDelegate : UIResponder <UIApplicationDelegate, UITabBarControllerDelegate>

@property (strong, nonatomic) UIWindow *window;
@property (nonatomic, strong) UITabBarController *tabBarController;
@property (nonatomic, strong) UINavigationController *navController;
@property (strong, nonatomic) Device *deviceInformation;
@property (nonatomic, strong) GSFeedViewController *feedViewController;
@property (nonatomic, strong) GSExploreViewController *exploreViewController;
@property (nonatomic, strong) GSCreateGroupViewController *createGroupViewController;
@property (nonatomic, strong) GSMessagingViewController *messagingViewController;
@property (nonatomic, strong) GSProfileViewController *profileViewController;

@property (nonatomic, readonly) int networkStatus;

- (BOOL)isParseReachable;
+ (GSAppDelegate *)sharedDelegate;
- (void)presentTabBarController;
@end

我尝试了stackoverflow返回给我的有关此错误的所有解决方案。任何建议表示赞赏！

故事板：

非常简单。我通过代码来做最多的事情。