iOS应用程序尝试在目标上推送一个nil视图控制器<uinavigationcontroller：

Question

=“”

XMPP 使用tableview我试图用特定的用户名转到下一个视图控制器。所以我已经正确地实现了UItablevie的didselectrowatIndexpath。但是当我点击用户名时，它会给出这样的错误。

  

应用程序试图在目标上推送一个nil视图控制器。

     

“＆lt;”UINavigationController：0x7fe831dac0d0＆gt;。   2015-06-04 14：22：51.063

我已经在appdelegate.m中宣布了故事板。

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
      ChatViewController *ChatViewController1 = [[ChatViewController alloc]init];
self.storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];


return YES;
}

这是我的tableview的Delegate方法。

 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
 {
[self.tblvwbuddy deselectRowAtIndexPath:indexPath animated:YES];
XMPPUserCoreDataStorageObject *user = nil;
user = [[self fetchedResultsController] objectAtIndexPath:indexPath];

ChathistryViewController *chathistory1 = [[ChathistryViewController alloc] init]; // or initWith...
chathistory1 = [appdelegate.storyboard instantiateViewControllerWithIdentifier:@"ChathistryViewController"];//My next view controller's name
     chathistory1.chatUserObject = user;

      chathistory1.hidesBottomBarWhenPushed = YES;

chathistory1.self.tabBarController.navigationItem.title = user.displayName;

[self.tabBarController.navigationController pushViewController:chathistory1 animated:YES];

}

我错过了什么？或者我错了？

Answer 1

试试这个：

 UITabBarController *vc = [self.storyboard instantiateViewControllerWithIdentifier:@"main"];
        NSArray *listViewController=vc.viewControllers;
        vc.selectedViewController=[listViewController objectAtIndex:1];
        [self presentViewController:vc animated:YES completion:nil];

ps .... listViewController objectAtIndex：1＆lt; ---表示你想要显示你的viewcontroller的位置

Answer 2

修改

          id: 1
  select_type: SIMPLE
        table: categories
         type: ALL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: 4
        Extra: 
1 row in set (0.00 sec)

结束修改

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
     ChatViewController *ChatViewController1 = [[ChatViewController alloc]init];
     self.storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];

     //HOW DID YOU DECLARE the rootViewController?
     /*
     you CANNOT do this: 
     self.window.rootViewController = ChatViewController1;
     */

     //you MUST have declared it like: right? becuase your are using navigationController
     UINavigationController *navigationView = self.storyboard instantiateViewControllerWithIdentifier:@"naviController"/*Storyboard ID*/];
     self.window.rootViewController = navigationView;

     //Manually setting navigationController rootViewController, example your rootViewController is ChatViewController
     UIViewController = self.storyboard instantiateViewControllerWithIdentifier:@"ChatViewController"/*Storyboard ID*/];
     [navigationView setViewControllers:UIViewController animated:NO];

     return YES;
}

在您的情况下，您必须设置自定义类：（ ChathistryViewController ）

确保您的故事板中存在 chathistory1 = [appdelegate.storyboard instantiateViewControllerWithIdentifier:@"ChathistryViewController"];troller Storyboard ID

来自您的代码：

ChathistryViewController

我觉得分配它更好：

chathistory1 = [appdelegate.storyboard instantiateViewControllerWithIdentifier:@"ChathistryViewController"];

更好的分配：

//From your code [[ChathistryViewController alloc] init]; will be use less
ChathistryViewController *chathistory1 = [[ChathistryViewController alloc] init]; 
chathistory1 = [appdelegate.storyboard instantiateViewControllerWithIdentifier:@"ChathistryViewController"];

另一个是你的ChathistryViewController *chathistory1 = [appdelegate.storyboard instantiateViewControllerWithIdentifier:@"ChathistryViewController"];

你在哪里宣布[appdelegate.storyboard instantiateViewControllerWithIdentifier:];？

您可以通过以下方式访问AppDelegates属性：

appdelegate

Answer 3

我猜你的故事板没有正确初始化，因为你得到了错误。

不是在委托类中创建storyboard对象，而是按照以下方法检索故事板对象。

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:[NSBundle mainBundle]];

让我知道它是否有效。