添加子视图后 self.navigationController 为零
这是我的 productscontroller.h
ProductListViewController *productListViewController;
ProductGridViewController *productGridViewController;
UIButton *flipIndicatorButton;
，我在实现中添加列表和 gridview 作为子视图
ProductListViewController *listController = [[ProductListViewController alloc] initWithNibName:@"ProductListView" bundle:nil];
self.productListViewController = listController;
self.productListViewController.CurrentSale = CurrentSale;
[self.view insertSubview:listController.view atIndex:0];
，但是当我尝试从 ProductListViewController.m 推送详细视图控制器时，这样它
ProductDetailViewController *productDetailViewController = [[ProductDetailViewController alloc] init];
productDetailViewController.productIndexPath = indexPath;
[self.navigationController pushViewController:productDetailViewController animated:YES];
不起作用，然后我检查 [self.navigationController] ，为零， 现在如何处理这个问题。我准备提供更多代码和细节以使其更加清晰。谢谢
here is my productscontroller.h
ProductListViewController *productListViewController;
ProductGridViewController *productGridViewController;
UIButton *flipIndicatorButton;
and i am adding list and gridview as a subview like this in my implementation
ProductListViewController *listController = [[ProductListViewController alloc] initWithNibName:@"ProductListView" bundle:nil];
self.productListViewController = listController;
self.productListViewController.CurrentSale = CurrentSale;
[self.view insertSubview:listController.view atIndex:0];
but in when i tried to push detailview controller from ProductListViewController.m like this
ProductDetailViewController *productDetailViewController = [[ProductDetailViewController alloc] init];
productDetailViewController.productIndexPath = indexPath;
[self.navigationController pushViewController:productDetailViewController animated:YES];
it just does not work, then i check [self.navigationController] , it was nil,
now how to deal with this problem. i am ready to give some more code and detail to make more clear. thanks
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您在哪里创建导航控制器？在某些时候（可能在您的应用程序委托中）您必须有这样的东西：
然后将 navController 的视图作为子视图添加到您的窗口中。
另一件事是您似乎在一个屏幕上使用了太多视图控制器。 Apple 建议每个屏幕仅使用一个。
Where are you creating the Navigation Controller? At some point (probably in your App Delegate) you have to have something like this:
And then add the navController's view as a subview to your window.
The other thing is that you appear to be using too many View Controllers for one screen. Apple recommends only one per screen.
我最近也遇到了同样的问题！我在视图控制器的 viewWillAppear: 方法中“弹出”（[self.navigationController popViewControllerAnimated:YES]）视图控制器。所以我只是删除了这段代码并在 viewDidAppear: 方法中插入了相同的代码，它就起作用了！
I had the same problem recently! I "poped" ([self.navigationController popViewControllerAnimated:YES]) the viewController in the viewWillAppear: method of the viewcontroller. So I just removed this code and inserted the same code in the viewDidAppear: method and it worked!
我找到了解决这个问题的方法。
现在我正在做的是在本例中传递父控制器的引用 ProductsController 和写入的方法来推送下一个视图。接下来，我现在正在调用父方法来推送下一个视图，如下所示
[父pushNextview];
到目前为止，它运行良好，希望这是做我想做的事情的好方法。
i found workaround for this problem.
now what i am doing is i am passing ref of parent controller in this case ProductsController and written method to push next view. following this now i am calling parent method to push next view like this
[parent pushNextview];
so far it works fine, hope this is good way of doing what i wanted to.
我昨天遇到了类似的问题：
Tab Bar View - Table View - View在表视图控制器中，我想推送“详细视图”控制器，但是
[self navigationController]code> 这里是nil。解决方案是采用以下安排：Tab Bar View - Navigation View - Table View - View使用附加导航控制器，
[self navigationController]现在可以在表视图中工作控制器。I ran into a similar issue yesterday:
Tab Bar View - Table View - ViewIn the table view controller, I wanted to push the "detail view" controller, but
[self navigationController]wasnilhere. The solution was to go to this arrangement:Tab Bar View - Navigation View - Table View - ViewWith the additional navigation controller,
[self navigationController]now worked in the table view controller.我刚刚发现为什么 navigationController 总是为零。您的整个视图系列应该包含在 UINavigationController 中。这意味着层次结构中的第一个视图必须是 rootViewController。 bpapas 代码应该可以工作。
I just found out why the navigationController is always nil. Your whole series of views should be contained in a UINavigationController. This means that the first view in your hierarchy will have to be your rootViewController. bpapas code should work.