So UIKit Framework Reference describes UINavigationController as an efficient way to present data and views to user. But I'm curious as to the performance and manageability differences between using UINavigationController VS SegueOnly.
There must be certain situations that one is better-suited than the other. I am entirely new to coding but instinctually I imagine UINavigationController is more for presenting VC's that each have a lot going on and user spends much time on each VC equally or that multiple VC's need to be running and holding data at same time. And that Segue are more for Uni-directionally VC progression or short-use, low-data VC presentations. Are any of these assumptions correct?
What are the PROS to implementing a UINavigationController?
This is an Apples to Socket-wrenches comparison. A navigation controller versus a segue isn't even an option. They don't fill the same role. You can use a navigation controller with or without using segues. You can use segues with or without a navigation controller.
A UINavigationController is a specific type of view controller. Specifically, it is designed for controlling a navigation stack of view controllers. When a user moves forward through your app, you add other view controllers to this navigation stack (either through segues or through other methods available on the view controller to present other view controllers). Meanwhile, the navigation controller allows you to "pop" controllers off the stack and we go backward to the previous view controller.
When we're comparing a UINavigationController to things, we should compare it to things like UITabBarController, or UISplitViewController, or UIPageViewController. These are other types of view controllers that control the way in which a user navigates through our app.
Segues exist as a means to get from one view controller to another. But the various controllers I just listed exist as a means for controlling the navigational relationship between your controllers.
If you are using storyboards for building your app, I highly recommend that you use segues. Whether or not you use a navigation controller is entirely up to the way you want your application navigation to work.
Perhaps some pictures might make the distinction more clear?
Exhibit A
Here we have two view controllers. No navigation controller, nothing. Just two normal controllers. The line with the arrow between the view controllers is the segue. The segue defines a relationship between the view controllers which lets us get from the one on the left to the one on the right.
Exhibit B
Here we have a navigation controller, followed by two view controllers. The line between the navigation controller (far left) and the first view controller (middle) is not a segue. However, it does define a relationship between the navigation controller and the view controller. It defines the view controller as the navigation controller's root view controller. Whenever we present this navigation controller, it will in turn present this view controller as the first controller on its navigation stack. The line between the first view controller (middle) and the second view controller (far right), however, is a segue. It's identical to the segue from exhibit A (except exhibit A is probably a different type of segue). This segue defines a relationship between the first and second view controller and provides us with a means of getting from first to second.
Exhibit C
Here we have a tab bar controller (far left) and four view controllers. We also have a bunch more lines connecting these things. Much line in the navigation controller example, the lines between the tab bar controller and the view controllers are NOT segues, but they do define a relationship between the tab bar controller and the view controllers. These lines assign the view controllers as part of the tab bar controller's viewControllers array, which determines what tabs to display. The lines between the left view controllers and the right view controllers, however, are segues, exactly the same as the first two examples.
A segue is nothing more than a way of defining a navigational relationship between two view controllers on your storyboard. If you weren't using a storyboard, you also wouldn't be using segues at all, but you could still make your app navigate in the exact same manner (this can all be achieved programmatically without the storyboard and without segues--and I don't think it effects performances on way or another).
Whether or not to use a navigation controller is another question and an entirely separate question at that. Whether or not to use a navigation controller isn't even remotely in the same ballpark to whether or not you're using segues. Using a navigation controller also isn't a question of performance. The overhead for using a navigation controller is extraordinarily minor. Most of the overhead for it probably comes from the UI stuff it adds... but if you want that UI stuff, you're going to have that overhead whether or not you have a navigation controller.
Importantly, whether or not to use segues isn't a question of performance--it's merely a question of whether or not you're designing your app using storyboards. And equally importantly, using navigation controllers isn't a question of performance--it's a question of how you want your app's navigation to look and feel. "Is a navigation controller the right look and feel for your app?" is literally the only question you have to answer when deciding whether or not to use a navigation controller.
Related
Is it possible to launch an app to a specific level of a navigation stack using a storyboard?
I'm looking to recreate the model employed by Mail.app, where the app launches into the Inbox, but this is actually one level down the navigation stack, and tapping the back button takes you to the root...
I understand how this can be done via code, i.e. instantiating the navigation controller within the app delegate and then manually pushing the view controller(s) to create the desired stack, but I'd really like to know if there's a way to achieve the same using storyboards.
Unfortunately I don't think there is because you need to instantiate your navigation controller at some point that will house your view controllers, and if you do this through storyboards the best you can do is set the navigation controller to be the entry point.
However, it is pretty straightforward to do from code. If your navigation controller has two view controllers where ViewControllerOne pushes to ViewControllerTwo, then you can just can just push to the second one without an animation as follows:
navigationController.pushViewController(secondViewController, animated: false)
And the user will be one level deep in the navigation controller.
So I have a navigation controller that is at the beginning of a series of view controllers. The series consists of 5 view controllers, but I want the navigation controller to only use the first 4 view controllers. Im not sure if there is a way to change the relationship between view controller 4 and view controller 5 so that view controller 5 and the rest of the app are not affected by the navigation controller.
Im not sure if there is a way to change the relationship between view controller 4 and view controller 5 so that view controller 5 and the rest of the app are not affected by the navigation controller.
There are a number of things that you could do:
Remove the navigation controller entirely and make your "view controller 5" the window's root view controller.
Set the navigation controller's array of view controllers to an array that contains only "view controller 5." This would effectively make that view controller the navigation controller's root controller, and from there you could just never push another controller onto the navigation stack.
Keep the current relationship, but hide the navigation bar and prevent the user from going back to "view controller 4."
Rethink your user interface. For example, if your first four view controllers are meant to lead the user through some set of initial questions, a login procedure, etc., then you could make "view controller 5" the app's main view controller, and present the navigation controller containing the controllers 1-4 modally.
Of those, and without knowing what you're actually up to, I believe reconsidering your UI is probably the best plan. Users should generally be in control of your app instead of the other way around, and they should never wonder why they can't get back to some part of the app that they've seen before. Also, it's poor form to break behaviors that users have learned to expect, and changing the user's ability to navigate through a series of view controllers would be a prime example. Using a modal presentation of the navigation controller with the first four view controllers should be fine, though.
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'm curious about what's the best way to plan the controllers for my app.
i want my main screen to have 3 button.
1) should open a nav controller with details view
2) should open a controller with other buttons that lead to others controllers
3) should open a tab bar with 2 pages ( or eventually use a switch to change page instead of the tab bar)
this is the schema of what i want
http://i59.tinypic.com/2rrvrd4.png
Is it a correct schema or i should use my controllers differently? will apple reject an apple with such schema?
thanks
As #Fogmeister pointed out in the comments, going for a UITabBarController as the main interface for your app actually seems to be a more appropriate solution here.
However, you can go with the interface that you described, but then you should keep in mind that with your current setup, you are not only using UINavigationController in the first case, but your whole navigation system is still built upon UINavigationController in the following way:
Your app has one instance of UINavigationController.
Your initial UIViewController (the one with the three buttons), is the rootViewController of your UINavigationController.
You can navigate to the other view controllers using [self.navigationController pushViewController:newViewController] (or performSegue if you prefer using Storyboards).
In the case of your third view controller, you are pushing a UITabBarController onto the navigation controller's view controller stack, this UITabBarController needs to be initialized with the two view controllers that it is going to display before it gets pushed onto the stack.
I understand that view controllers help control multiple views in an application, but I have trouble understanding when to use them.
If I have an application with a main page, several views with a "hierarchy" structure, and an about page not connected with the hierarchy, what files should my application have? An appdelegate, navigation controller and view controller? More than one view controller? Just a navigation controller?
Also, should they all be contained in one .xib file, or multiple .xib files?
Any help would be greatly appreciated.
Thanks.
A good habit is to have a UIViewController for each page you want to show. If I get the structure of your app you should have a main page (with many other UIViews inside it) and another page (about page). If that's true I suggest two UIViewControllers.
The UINavigationController is a subclass of UIViewController that lets you "navigate" among the pages. It's not strictly necessary but suggested (you can also implement your self a custom navigation system, but it's easier to exploit the one Apple offers you). Another navigation system is the one based on UITabBarController, if you want to take a look.
Assuming I get the structure of your app you should need two .xib file, one for each page you have.
The app delegate is conceptually different from a view controller, you'll have just a single app delegate, automatically created by Xcode (you can, of course, modify it to fit your needs).
Each "screenful of content" (Apple uses this term) should be handled by it's UIViewController or more likely a subclass of it. The point of view controller is to handle view appearing or disappearing (going on/offscreen), device rotation, memory management, navigating to other view controllers and so on. If you are creating your UI with IB, then each of those view controllers would most likely have it's own .xib file.
Each view controller has one view (it's view property) that acts as main view for each "screenful of content" to which you then add your subviews.
UINavigationController and UITabBarcontroller are there to help you control the hierarchy of your app. They only act as containers for other view controllers and don't contain any UI except navigation bar or tab bar. Using tab bar controller you can have multiple view controllers which act exactly like browser tabs. Using navigation controller you can have a stack-like navigation where new view controllers are pushed from right to left and are popped from left to right when user goes back to previous view controller. You can even have a view controller inside navigation controller inside a tab bar controller.
If you don't want to use tab bar or navigation controller, you can navigate through your view controllers by presenting them modally using presentModalViewController:animated: and dismissing by dismissModalViewControllerAnimated:. If you send YES for animated parameter of these methods, you will get an animation specified by the modalTransitionStyle property of view controller being presented or dismissed. Possible animations are slide in from bottom (default), horizontal flip of entire screen, fade in/out and half-page curl.
There are also some Apple-provided subclasses of UIViewController that help you setup your UI quicker like UITableViewController which is basically a view controller that contains a table as it's main view and conforms to 'UITableViewdataSourceanddelegate` protocols which are required to define how each cell looks and what it contains.
On iPad there is one additional container controller UISplitViewController and one additional way to present new view controllers using UIPopover.