什么是错误“应用程序尝试在目标上推送零视图控制器。”？

Question

我的编码是

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

FirstTabBarItem = [[FirstMuseum alloc] init];
SecondTabBarItem = [[SecondMaps alloc] init];
ThirdTabBarItem = [[ThirdExhibition alloc] init];
FourthTabBarItem = [[FourthTabBarItem alloc] init];


first = [[UINavigationController alloc] initWithRootViewController:FirstTabBarItem];
second = [[UINavigationController alloc] initWithRootViewController:SecondTabBarItem];
third = [[UINavigationController alloc] initWithRootViewController:ThirdTabBarItem];
fourth = [[UINavigationController alloc] initWithRootViewController:FourthTabBarItem];


first.title = @"Hello";
second.title = @"Hello";
third.title = @"Hello";
fourth.title = @"Hello";

myControllerArray = [[NSMutableArray alloc] init];

[myControllerArray addObject:first];
[myControllerArray addObject:second];
[myControllerArray addObject:third];
[myControllerArray addObject:fourth];


myTabBar = [[UITabBarController alloc] init];

[myTabBar setViewControllers:myControllerArray];

localNavigationController = [[UINavigationController alloc] initWithRootViewController:myTabBar];

NSLog(@"Hello, You Tapped !");  }

什么错误， 我正在尝试制作一个包含四个项目的 UITabBarController，所以现在我应该做什么 ????

Answer 1

这意味着您尝试推送的视图控制器尚未正确分配。请检查视图控制器的分配情况，看看它是否分配干净

Answer 2

是的，你可能忘记分配视图控制器，所以试试我的代码：

按钮操作

_forgotviewcontroller means my second view property eg:

@property (nonatomic,strong) ForgotPassword *forgotviewController;

1）tapaction意味着在我的第一个视图中声明的

-(void) tapAction:(id)sender
{
    _forgotviewController=[[ForgotPassword alloc]init];
    [self.navigationController pushViewController:self.forgotviewController animated:YES];
}

尝试这个你会得到导航