I've been working on an iPad application that has about 15 view controllers. Some of the view controllers are full screen, others are embedded inside the other view controllers (think split view controller).
On the iPhone navigation is very straight forward. Even if you have a ton of view controllers, you are using one of Apple's root view controllers (tab or navigation). The navigation is handled by the root view controllers and you are pretty much free to focus on your views.
On the ipad the split view and tab view controllers are not always useful, and for the app I'm working on they do not cut it. I have created separate navigation controller objects to handle hiding/show view controllers based on notifications that get posted when the user performs actions.
Anyone else have experience with solving the navigation problem on the iPad?
have you checked out MGSplitViewController by Matt Gemmell?
http://mattgemmell.com/2010/08/03/mgsplitviewcontroller-updated
I'm not claiming it'll solve all your navigation problems, but it's an interesting idea and may help you in finding more/better ways of handling view controllers.
With iOS 5 Apple has added the concept of Container View Controllers. This makes adding and removing children easy, allowing their methods for rotation/appear/disappear to be called automagically. Cool stuff!
Also, be careful using multiple view controllers for views which don't fill the full screen. Apple's documentation explicitly states that you shouldn't use view controllers for partial-screen views:
Note: You should not use view controllers to manage views that fill only a part of their window—that is, only part of the area defined by the application content rectangle. If you want to have an interface composed of several smaller views, embed them all in a single root view and manage that view with your view controller.
http://developer.apple.com/library/ios/#documentation/uikit/reference/UIViewController_Class/Reference/Reference.html
Although some things might work when you have multiple view controllers managing different sub-views, other things won't work. For example, only one of your view controllers will be informed when the device is rotated. Likewise, not all your view controllers will be sent 'viewWillAppear' 'viewDidUnload' etc messages that you might expect.
Related
Let's say I have two pages with two UIViewControllers, UIViewController1 & UIViewController2.
If I want to show a UIViewController2 on top of UIViewController1 I have three options:
using UINavigationController pushViewController.
using presentViewController.
addSubView : UIViewController1.view.addSubView(UIViewController2.view)
If I need to a transition between my views, I prefer the third option because it gives me much more control over the views.
Is there any difference between these three options in terms of performance?
Before iOS 6 you were not supposed to do option 3. View controllers were meant to control the entire screen. In iOS 6 Apple added support for parent and child view controllers. You could make another view controller your child and add it's content views to yours.
If you are going to use option 3 then that's what you need to do. If you don't you will have a variety of problems.
There is even support for parent/child view controller built into storyboards. You can add a container view to a view controller, and then control drag from the container view onto another view controller's scene. When you do that the system creates an "embed segue" that sets up the child view controller inside the container view and wires up the parent/child relationship for you.
Your first 2 options are for when you want the new view controller to replace, or at least cover, the first view controller. Option 3 is for when you want a region of your screen to be managed by another view controller.
Option 3 (using a child view controller) does mean that both view controllers will be active and in memory at the same time, so you can't release the covered view controller's data storage while it's inactive like you can in a push or modal presentation. However unless your view controllers hold and present huge data structures this isn't much of a concern. In both a push and a modal presentation the covered view controller sticks around in memory anyway, waiting to be uncovered. You have to take special steps in order to free any memory while a view controller's view is covered and then reallocate it when it is displayed again - something that is unusual.
Just for two view controllers, it will not create major difference. UINavigationController is mainly used to maintain navigation stack.
But as you are having just two view controllers, you can use alternate way also.
If you are looking for transitions with NavigationController, you can use UIView Transitions for customisation of push pop animation.
Please refer following links for UIView Transitions
https://www.objc.io/issues/12-animations/custom-container-view-controller-transitions/
http://www.raywenderlich.com/86521/how-to-make-a-view-controller-transition-animation-like-in-the-ping-app
https://www.captechconsulting.com/blogs/ios-7-tutorial-series-custom-navigation-transitions--more
http://applidium.github.io/ADTransitionController/
I'm new at objective-c programming and I need help clearing some doubts about the split view controllers. I understand that if you use a split view controller in your app then it must necessarily be your root view and I was wondering if there was any way to get around it.
I mean, I need to use split view controllers in my app but only in a couple of views, and for the rest just use simple views. If anyone has any idea or suggestion as to how to do this I'd be really grateful.
There are several things you can do. You can present your simple views modally, which will cover up the split view controller, or you can switch out the window's root view controller when you're done with the split view. Which to do depends on how and where in your app you use the split view. If you are going back and forth to it, then I would use the first method, if you're using it once, then going to the simple views, I would use the second method.
You can add split view controllers as children of tabbarviewcontrollers. Also, you can add split view controllers into container view controllers you build.
I am exploring the design options for an iPAD application with multiple views on the different part of the main screen. I am going to have different ViewController for each of the view. UI is quite different from what any of the available view controllers (UISplitViewController, UINavigationController etc.) provide. I have been reading about the container extension api of UIViewController (especially addChildViewController):
http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UIViewController_Class/Reference/Reference.html
(Look for "Implementing a Container View Controller")
However, it seems to me that this functionality is mainly designed for applications with UI that transition from one view to another (transitionFromViewController...). In my case, all of the views are visible at the same time. However, they do interact with each other. So my questions:
Am I missing something w.r.t. container extension of View Controller? I will still probably end up using this just to keep the list of child view controllers but don't see much value.
Can you recommend any other api/pattern that I should be using?
Thank you.
You can easy access to childViewController.
self.childViewControllers will return an array with all childs.
I asked similar question couple days ago: Maybe this will help you:
Get container VC instead of view
Take a look at http://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/CreatingCustomContainerViewControllers/CreatingCustomContainerViewControllers.html.
Add your various view controllers to self.childViewControllers and add the views of the child controllers as subviews of self.view.
I have a offlineMapVC and a onlineMapVC for my application to support both online maps (using MapKit and Google Maps) and offline maps (using Route-Me).
I made my own mapVC to manage the switching of these mapVCs and be able to use the view controller as one separate view controller. Well I've done this by making the offlineMapVC and the onlineMapVC instance variables of the new mapVC witch I now use all over my application.
First off all things seem to work but. However while using this approach for a longer time I ran into some problems due my using of View Controllers in a hierarchy. I read this is the wrong way to go. What is the right way to manage the switching between two view controllers? My question seems fairly simple but I couldn't find a decent solution.
I put view controllers in view controllers, myself, and I have seen much better programmers than me doing the same thing. (See Rob Napier "iOS 5 Programming - Pushing the Limits". He mentions it frequently.) As long as you don't have more than one view controller directly controlling the same views and subviews, you should be okay with it.
Since Jonah Williams wrote that article, I think iOS 5 formalized the use of view controller hierarchy with custom content view controllers. You might consider your mapVC to be a custom content view controller and implement onlineMapVC and offlineMapVC as child view controllers.
(Apple documentation links tend to change frequenctly, so Google "Custom Content View Controller" for the documentation.)
If you can give some more context to what you mean by "switching between two view controllers" that would help answer your question. Generally, I have more than one view controller active at the same time. I don't switch between them. (I use navigation and tab bar controllers in the same applicaiton, but I assume you are aware of how those work and you're asking a different question. It's just not clear what the detials are in your case.)
From Apple: "You should never present a split view inside of a navigation or tab bar interface."
They don't say why, and they only say "should" not. What would happen if I do it? I can imagine so many good use cases where I would want to!
Your application may crash. The UISplitViewController was designed to be the root view controller in the VC stack.
SO Question:
Split view controller must be root view controller
Also, as stated in the Class Reference:
The split view controller has no
significant interface of its own. Its
job is to coordinate the presentation
of its two child view controllers and
to manage the transitions among
different orientations.
I wrote this question which is related. As Evan notes, usually you just have to roll with Apple's damands. I tried to work around their restrictions; it failed horribly. UISplitViewController is extremely fragile if you do anything Apple don't want you to.