I've seen a lot of other questions on here about adding a UINavigationBar to a UIPopoverController. All of the examples I've seen follow one of two patterns:
In the init or viewDidLoad method of the Popover subclass, you alloc-init a UINavigationBar directly, as suggested here. This method is a little hacky, and while it shows up nicely, if the popover is a UITableViewController, you have to mess with a bunch of things to make sure the navigation bar you just added doesn't overlap one of your cells.
Alternatively, a lot of post suggest creating a UINavigationController just before presenting the popover, as shown here.
With the second method, however, won't the popover be the only controller in the newly created navigation controller? And if my view that I'm presenting the popover from is itself already in a navigation controller, the popover will NOT be in that same navigation controller, correct? It seems to be that the more appropriate thing to do would be to add the popover being created as another controller in the navigation controller that already exists (and which the controller that presents the popover is already a part of). Is that possible? Or is there a reason why the navigation controller for the popover needs to be independent from the navigation controller for the presenting controller? Or am I totally missing something here?
You have many questions, young Skywalker. :)
Creating a UINavigationController and then embedding the controller you would like to present is the way to go.
Don't get confused by all the controllers involved here:
UIPopoverController is a construct that shows an existing UIViewController in an overlay like style. UIPopoverController itself even isn't a subclass of UIViewController. The name is misleading.
So UIPopoverController hosts another controller. In your case, we let it host a UINavigationController.
UINavigationController is a subclass of UIViewController. It is a container controller and can handle a stack of UIViewControllers.
On that stack we push one UIViewController: the one you want to display and garnish with a UINavigationBar. Since Mr. UINavigationController comes with a build in UINavigationBar, he's our friend.
There is no need to subclass UIPopoverController. You just keep one static reference to it around so you can dismiss the current open popover in case you want to present another.
It does not matter where you present the UIPopoverController from. It will always be a popover. Even if presented from an existing UINavigationController. Only if you use presentViewController: you will get different results depending on the controller you're presenting from (modal or pushed on top of the stack).
won't the popover be the only controller in the newly created navigation controller?
No, the popover will contain the navigation controller and the navigation controller will only contain its root view controller (which would otherwise have been added directly to the popover as its root).
You seem to be a little confused about the relationship between the popover and the popover root view controller...
the popover will NOT be in that same navigation controller, correct
Yes, correct. The popover is effectively a window floating above all other views
Or am I totally missing something here?
Maybe... The popover would usually be used for displaying something modal, transient and smaller than full screen size. Putting a navigation controller in the popover and adding views to it is the normal approach.
Adding a navigation bar to a popover isn't hacky. A navigation bar is just another regular view. That also means that using a UITableViewController with it, the navigation bar will overlap the table view, as the UITableViewController's view property just returns the controller's tableView property. If you want to add a navigation bar above a table view, without it overlapping the table view, use a regular UIViewController and add your navigation bar and table view the normal way. UITableViewController should only be used if your only view within that view controller is a table view.
Having said that, I do agree with others that just using a navigation controller without using its navigation features is the most common approach.
Related
So far, I have two distinct uses of a navigation bar in my app: one produced by a Navigation Controller with a View Controller embedded in it and one added manually from the Object Library into a different View Controller presented modally (since a modally presented view apparently doesn't inherit the navigation controller of the view under it).
My question: do either of these navigation bars require constraints?
Yes, the one added by you, as it is managed by you. The other one is managed by UINavigationController. Also it wouldn't make sense for a modal controller to have the navigation bar of its presenter - you are showing an "extra" screen, not navigating the hierarchy. It is also worth mentioning that nothing stops you from presenting another UINavigationController modally with a separate navigation flow.
We often try to reuse our view controllers, whether they get pushed to a navigation controller or are presented. However, things can get a little hairy when an explicit UINavigationBar is part of the view controller's function design.
If we just set the view controller's navigation item, pushing to a navigation controller works as expected, but presenting results in no navigation bar at all. On the other hand, if we explicitly add and configure a UINavigationBar to the view, presenting works fine, but pushing results in double navigation bars. While we could specify the parent navigation controller's navigation bar to be hidden for that view, it creates a clumsy animated transition when pushing or popping that view controller.
(In a perfect world, I would imagine that the navigationBar property would be managed by UIViewController instead of UINavigationController. Alas, that's not the case, so here I am.)
What are some of the best practices people here have found to maintain the portability of view controllers requiring a UINavigationBar?
I've handled this in one of two ways:
I fall back to asserting viewDidAppear: that self.navigationController is non-nil. Push the responsibility of providing a UINavigationController to wrap your view controller instance to clients of the class.
Alternatively, you can embed a UINavigationBar instance and manage it yourself, just remember to hide the possible navigation bar from your containing navigation controller in viewWillAppear:.
In my app, I have to show same NavigationBar for all UIViewControllers. This NavigationBar has three buttons and these three buttons which will be act as TabBar functionality, that is each tab has its own stack cycle. I have created custom view for NavigationBar with three buttons, but after adding this custom view to HomeViewController, I have to manually add this custom view for all other view controllers. I don't want to do this.
Is there any simple method to achieve this?
There are a couple of ideas that come to mind. First of all, you could use view controller containment and actually have 1 controller that implements your custom nav bar, and then swap out the contained controller as necessary.
If that's not feasible, you can simply use inheritance and have all your custom controllers inherit from a controller that has the nav bar in place.
Another option could be to write your own UINavigationController subclass. I'm not certain if you can override the UNavigationItem behavior, but if you can, you can just just do that -- instead of the UINavigationController taking its child's UINavigationItem to update its own UINavigationBar, the UINavigationBar perhaps just stays the same, like you're expecting/hoping.
I was going through Apple's documentation about navigation controller and find this point ambiguous and hard to comprehend.
It was written in this online documentation of navigation controller.
Navigation Controller Views
A navigation controller is a container view controller—that is, it
embeds the content of other view controllers inside of itself. You
access a navigation controller’s view from its view property. This
view incorporates the navigation bar, an optional toolbar, and the
content view corresponding to the topmost view controller. Figure 2
shows how these views are assembled to present the overall navigation
interface. (In this figure, the navigation interface is further
embedded inside a tab bar interface.) Although the content of the
navigation bar and toolbar views changes, the views themselves do not.
The only view that actually changes is the custom content view
provided by the topmost view controller on the navigation stack.
From that, my understanding is that inside this "view" property. There should be at least two subview inside this view.One is the navigationBar the other is the contentView of the current displayed viewController’s view. But while I am debugging only the navigation bar showed with another view called UINavigationTransitionView showed.
My question is, is this normal. Have I done anything wrong?
Second, what is the most common way to access current displayed viewController's view with only the reference to the navigation controller.
Thanks
UINavigationTransitionView controller contains one wrapper view which intern will have the current uiviewcontroller's view.
You can probably find this view as a subview of UINavigationTransitionView. However this is not the "right" way to do this. The proper way is to go through property "topViewController" and then take its view:
self.navigationController.topViewController.view
If there is another view controller or its view that you need, you have access to whole view controller's hierarchy across navigation controller through viewControllers property.
self.navigationController.viewControllers
More here:
https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UINavigationController_Class/index.html
I've spent the past few days searching on the web for a solution to my problem, however, I can't seem to find a problem similar to mine. I am using a TabBarController and on one of the tabs I have a segmented Control in the navigation bar that I would like to use to switch between view controllers. The problem is that when I present the second view Controller it appears over the tabbarcontroller. Is there anyway to keep the modally presented Navigation controller in the tabbarcontroller?
This is the first controller.
And this is the controller I am trying to present.
well we can't really comment unless we saw some code. But I think your problem may be to do with your view hierarchy. If I was going to build what you are attempting I would do as follows:
UITabbar controller that contains a custom navigation bar controller
The custom nav bar controller would contain the segment controller and have a protocol defined so that a delegate could be alerted when either segment was selected by the user.
The nav bar's root view controller would be a view controller that acted as a UIView container for the two screens you are displaying (friends and circle screens)
This root view controller would be the delegate for the custom nav controller so that it will know when the user selected a segment.
When the user selected a segment the root view controller would then switch between the friends and circles view controllers in the container.
To do the above have a look at the documentation for creating UIViewController Containers and working with delegates
Hope that helps!