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.
Related
I have a simple Navigation View Hierarchy that has 2 views it goes between. I wanted a customized navigation bar, so I have the default one hidden, and I've implemented a Container View which is shared between the 2 views in the nav hierarchy.
Everything works as I want it to, except when I segue to the lower or higher view the top bar appears slides away and reappears on the new view. I would like it to appear stationary when I push or pop to other views in the hierarchy.
Is there an easy way to do this? Or should I delete my custom shared Container View and try to make this work with the Navigation Bar (which I have currently "hidden")?
I had to do this for a client once. The way we did it was, like you said, make an encompassing view controller that housed a container view. Within this container view, we embedded a UINavigationController and would manually pop and push UIViewControllers to its navigation stack. Of course you want to hide the UINavigationController's nav bar.
It sounds like you sort of implemented this, but instead you just embedded a plain old view controller inside your custom navigation controller, and then segue to another view controller that is also embedded in the custom view controller? Ideally you want one instance of this custom nav controller with an embedded UINavigationController. I believe you will have to do all the view controller transitions programmatically.
Opinion: Personally, I would recommend against doing this. I believe that an app should feel like an extension of the OS it's on. A user should feel it's a part of their phone. Using the native navigation bar also decreases the level of effort a user is required to put forth to understand your app.
I know you're thinking "but it's just a nav bar" but we're talking about the same people that will potentially uninstall an app if it takes longer than 2.5s to load.
I wanted a customized navigation bar, so I have the default one hidden
That's your mistake. The way to get a customized navigation bar in a UINavigationController interface is to initialize it with init(navigationBarClass:toolbarClass:). Now the built-in navigation controller is using your navigation bar! And from there on, all will be well.
https://developer.apple.com/reference/uikit/uinavigationcontroller/1621866-init
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:.
Difference between navigation controller and viewcontroller?
I mean how can we decide when to use navigation controller or a normal view controller?
Just my two cents:
A UIViewController represents a single view and you can put buttons in this view controller to segue to another UIViewController. If you want to segue back to the first UIViewController, you will have to worry about putting a button in the second view controller that leads back to the first. If you are drilling down into view controllers, this can be tedious having to remember to give the user a way back to a previous view controller.
A UINavigationController does a lot of this tedious work for you. As mentioned, it contains a stack of UIViewControllers. It will create a navigation bar at the top that will allow you to easily go back up the hierarchy of view controllers.
In short, if you have a hierarchy of view controllers that you want the user to easily navigate around, inbed your UIViewControllers into a UINavigation controller.
UINavigation Controller is a combination of 2 or more view controllers,those are connected through "segue" feature of "Ios". Benefit of using Navigation Controller is that we can navigate between different screens easily with default "Back" button on each screen . We don't need to give any individual button to move back onto previous screen.
Whereas a ViewController provides a single screen & we can connect more screen using "segue" but we also have to design a "Back" button to navigate onto previous screen.
We should use Navigation Controller , in case where one option resides into another one.Like in an iPhone settings ->Mobile Data Options->Voice->4G or 3G or 2G. It's a hierarchy of menus so here navigation Controller is better option than using UIController.
We should use UiController with "segue " , in case where
we have to choose one option among multiple.Like -
Photos ->There are many folders in which , any one is selected, that are Favourites or People or Places .
Here's a very brief, high-level overview.
Whereas a UIViewController can be thought of as representing a single 'screen', UINavigationController, as the name implies, is used as a means of being able to navigate multiple 'screens'.
From the documentation:
The UINavigationController class implements a specialized view controller that manages the navigation of hierarchical content. This navigation interface makes it possible to present your data efficiently and makes it easier for the user to navigate that content. You generally use this class as-is but in iOS 6 and later you may subclass to customize the class behavior.
Please see the rest of the UINavigationController documentation here: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UINavigationController_Class/index.html
Okay, Thank you everyone for helping me to find out a clear answer on this.
Navigation Controller consists of navigation bar and tool bar to move in and out from view controllers present in navigation stack.Therefore there can be many view controllers in Navigation Controller.
In view controller we don't have this facility and it represents a single screen view.
Please correct me If I am wrong.
See the Navigation Controller discussion in the View Controller Catalog.
Bottom line, a navigation controller actually is a view controller, but it just happens to be one that presents and navigates between other view controllers.
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.
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!