One UINavigationcontroller for the whole app?

Question

i´ve created a UINavigationController in my appdelegate and initialized it with my "modelselectionViewController". This VC has different uibuttons and when touched, a new VC ("modelViewController") is pushed on the navigationstack.

This "modelViewController" acts as my template view and has a uitabbarcontroller with different tabs. The first VC is shown immediately but any changes on the navigationcontroller doesn´t work. I would like to set the name of the title but that navigationcontroller is null.

NSLog(@"navi: %@", self.navigationController);

If i change my code to push the different VC when touching the different tabs, navigation works but only with a third level of navigation hierachy.

I want to know if it´s possible to use only one navigationcontroller for all my different tabs. Hope i made my setup clear. Appreciate all your help. thanks

Answer 1

I think you might want to read Combining ViewControllers.

In general, you should have the tabbar controller as a 'root' controller, not as a 'child' controller. A quick search in Apple's doc didn't yield a formal 'forbidden', but it might be.

Answer 2

If you create a UITabBarController from a view that's managed in a UINavigationController (ie: if you create a navigationcontroller first, and it's still around when you create the tabbarcontroller), you're starting a fight with the frameworks. Here's the admonishment from the docs on combining viewcontroller interfaces:

An application that uses a tab bar controller can also use navigation controllers in one or more tabs. When combining these two types of view controller in the same user interface, the tab bar controller always acts as the wrapper for the navigation controllers. You never want to push a tab bar controller onto the navigation stack of a navigation controller. Doing so creates an unusual situation whereby the tab bar appears only while a specific view controller is at the top of the navigation stack. Tab bars are designed to be persistent, and so this transient approach can be confusing to users.

I read that as "if it doesn't break something that we haven't thought of on the next update, we might reject the app anyway because it's 'confusing to users.'"

I suppose you could kill the whole navigation hierarchy and the navigationcontroller if you don't need to return there (like if you just used it for a one-time setup screen). Or you can look into other options for navigating within a viewcontroller that's managed by the navigationcontroller.

One thing to try might be to navigate to a UITableView, and use its cells to push a modal view onto the navigation stack. That would be familiar to users and also jive with the intent of the navigation classes.