Quite possibly I'm missing something obvious, but I have a very simple requirement and neither of these two seems to meet it.
I have an application with 3 distinct views, however for reasons I won't go into here (essentially views may or may not be valid depending in what is done in other views), using persistant tabs as navigation will not work. I also want each view to be created as needed and UITabBarController creates all its views upfront. However I still want some of the functionality of UITabBarController - being able to pass it in an Array of UIViewControllers.
UINavigationController offers the chance to have it create its views as needed, but there is no way for me to pass a list of views to it up front, so I end up with ViewControllers creating and pushing other (sibling) ViewControllers which is nasty.
So here are my requirements:
I want to be able to add ViewControllers upfront
I want to be able to navigate between the view controllers
I want each ViewController to be created as needed and destroyed when navigated away from
Is there anything that fits the bill?
I would use the AppDelegate to create a hash of viewcontrollers upfront and create a navigation controller.
Once you click the button to navigate to a new viewcontroller you can go to the hash and look for that specific view controller. If it is not created you can create it there. If you want to destroy that view controller just release it and remove from the hash.
Related
I'm trying to do a project for the iPad in which I'd like to utilized the split view controller. I'll be having different detail view controllers for each of the cells in the master view controller.
I saw one solution how to do this via storyboard segues in this site.
He basically linked each of his UITableViewCell to different detail view controllers. But I'd like to know if this is a "stable" or a "good" way of doing this. I mean, is it any better or as stable as doing it programmatically? What would be the consequences of doing his method, if there are any?
Here is the link to the solution I found
This is kind of a tricky one, even though it's an incredibly common use case.
1) One idea is to have an empty root view controller as your detail and it handles managing segues under the hood to quickly segue to the detail view you actually care about, utilizing the "replace" segue. This should "technically" fix having the "back" button at the top left and still allow you to pop to root and not have it show the empty controller. Haven't tested these though, so I'm not sure.
Edit: In Xcode 6, the "replace" segue is conveniently handled by a "show detail" segue which is used specifically for this type of view handling on Split View Controllers. I recommend using this method exclusively in new projects. See sample code.
2) The other idea is to have separate navigation controllers in your storyboard (one connected, the rest all stranded). One for each detail view type and tapping on the master menu will simply swap the navigation controller for the detail view to the one you care about.
Code similar to this in AppDelegate:
self.detailNavigationController = [self.masterNavigationController.storyboard instantiateViewControllerWithIdentifier:#"MyChosenNavigationControllerStoryboardId"];
self.splitViewController.viewControllers = #[self.splitViewController.viewControllers[0], self.detailNavigationController];
self.splitViewController.delegate = (id)self.detailNavigationController.topViewController;
The downside to this second way is that in memory tests, it doesn't appear that swapping a new nav controllers in frees up all of the memory that the old nav controller was using. So it's good to use for simple apps but not for anything crazy complex.
I'm trying to put an iAd banner in an app that is based on a UINavigationController (it's not the standard nav-base app proposed by xcode, cause I don't need the table view).
I'd like to place an ADBanner on its bottom, to be always visible, no matter how the user pops and pushes views.
I studied the iAdSuite example in the apple sample code, but, though it's reported among the "best practices", I don't think it's the best practice for what I need. It basically declares an ADBannerView in the app delegate class and then implements the ADBannerViewDelegate methods for every single view the app needs. That means implementing the ADBannerViewDelegate methods over and over again on every view controller class you need! It doesn't seem too smart... :(
I'd rather prefer to have an approach more similar to what Apple itself does in the tab bar based app, where you have a part of the window always occupied by the tab controller and all the views switching above without affecting the tab bar view below.
You can't directly put an ADBannerView along with the nav controller in the app delegate, because ADBanner needs to be placed in a view controller (you get a runtime error otherwise).
I tried to subclass from UIViewController, implementing the ADBannerViewDelegate in this class, and place it in the rootViewController along with a UINavigationController but I'm not having good luck with this approach...
Has anybody found a good, simple way to to this? Any hint?
Thank you for any help...
You can have just one class for ADBannerViewDelegate, and just one instance of ADBanner itself. When the currently active view changes, remove ADBanner from the old view, add it as a subview to the new view.
EDIT:
to clarify, you don't need each view implement the ADBannerViewDelegate. You only should have one class implement it (that class doesn't have to be a view controller for that matter).
You would also need to maintain a somewhere a property that would point to the currently active view (e.g. you can update that property in your Navigation Controller's navigationController:didShowViewController:animated:, or come up with your own protocol for that if your views appear in a more complex way).
Then in your ADBannerViewDelegate you'd just resize the view currently pointed to by that current view property. The actual view doesn't even have to know it has an ad in it ;)
I'm creating an iPad app based on a UINavigationController (with the bar hidden) so I can push and pop other viewControllers for navigation around the app. However, I am now wanting to add a section in which there are two viewControllers that I want to be able to switch between, so in other words they are side-by-side, rather than hierarchical.
Is it okay to use a UITabBarController for this? I am aware that on the iPhone it is recommended they are used only at the root level of the app, but since this is an iPad app I wondered if I could use it? Also, I guess I need to create an empty viewController, create a UITabBarController within it and set the delegate to it, then add the two viewControllers to it... So in effect I will have a viewController within another viewController, and when I have done that in the past the results have been very flaky.
Can I do it this way? The only other way I can think of doing it is to have two plan UIViews within a UIViewController, but that also means I shouldn't really put any business logic in them (bad MVC!), and not being able to will be a right pain in the a**.
Any ideas?
Thanks!
:-Joe
EDIT: I also need to be able to swipe-animate between the two VCs within the TabBarController, AND have a menubar over the top which doesn't animate... Can I do this?
Sure.
I do this kind of thing all over the place in an app I'm working on. I actually have several different types of "toolbars" that can be optionally shown at different times.
What I do is create a "parent" member in my toolbar's class - and when a button is pressed, I have the toolbar call a method in the parent class to do whatever needs to be done - (i.e. display another view).
This avoids the whole mess of creating a view inside another view (or viewcontroller inside another viewcontroller - or whatever) - the toolbar can take the button hits, but all the views are opened by the root view/controller.
Hope this helps/makes sense!
Can anyone suggest an article or perhaps an example of how to create an "infinite drill-down" with UINavigationController like you see in the Facebook, IMDB and BrightKite apps?
The UINavigationController is designed to be used this way. If memory becomes an issue, the nav controller will release hidden views and reload them when the time comes to navigate back down the stack. Apple recommends you load your UIViews from a NIB for this reason.
http://developer.apple.com/iphone/library/featuredarticles/ViewControllerPGforiPhoneOS/NavigationControllers/NavigationControllers.html#//apple_ref/doc/uid/TP40007457-CH103-SW28
Scroll down to item #4, "Configure the view for your root view controller."
Never having done this... I would approach this by keeping a stack with a light-weight object containing the contents of the previous view (perhaps just a URL?). Rather than just push on a new UIViewController to the UINavigationController, you would pop your current one, without animation, then push on the new view. However, I don't think this would properly handle the nice animation.
Another way that comes to mind would be to manipulation the viewControllers array of UINavigationController. After pushing on a new view, just remove the previous view from the array. That way the UINavigationController stack would only ever be 1 or two elements deep. Handling the back button would create the proper view, insert it into the viewControllers array, then pop off the current one. Your state would be managed by the lightweight object stack, not heavyweight view controllers.
-dan
I've got a fairly complex view, for me anyway, that has a few "trays" with custom interface items on them. They slide in and out of my root view. I'd like to nest (addSubview) the items inside the view. Each needs some setup before being displayed...and none can be configured in IB (they're subclasses of UIView).
I'm wondering if it makes sense to subclass UIViewController for each "tray" and then have the VC's view property point to the "tray" view which I can populate with my custom UIView objects. This way I can leverage the viewDidLoad, etc... methods in UIViewController.
I'm not aware of others doing this - at least in the few samples I've looked at. It would create a situation where there would be multiple view controllers being displayed on the screen at once. from the Navigation controller itself on down to the rootViewController and its view and then any number (well, screen size permitting) of these small trayViewControllers. If so, how's the responder chain work? i assume it'd go from lowest UIView to its enclosing VC, then to that VC's parent view, then that view's VC, etc. etc. repeat, repeat.. up to UIApplication... am I asking for trouble?
OR, do I just stick with UIViews and adding subviews into subviews, etc. etc..
Prior to iOS 5.0 this will specifically not recommended because the nested view controllers' lifecycle events – viewWillAppear, etc. – won't be called. See Abusing UIViewControllers.
With multiple UIViewController’s views visible at once some of those controllers may not receive important messages like -viewWillAppear: or -didReceiveMemoryWarning. Additionally some of their properties like parentViewController and interfaceOrientation may not be set or updated as expected.
iOS 5.0 added containment UIViewControllers that correctly handles those lifecycle events by adding child view controllers.
- (void)addChildViewController:(UIViewController *)childController
I spent countless hours trying to get nested view controllers to work in iOS 4. I eventually did, but it required a lot of glue code that was easy to get wrong. Then I saw the warning in the docs.
I'm trying to do the same thing, but was dissuaded from your approach by Apple's documentation, which states that "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."
My experience on what you are trying to do has been a good one. I try to keep nib files as simple as possible, so I take any posible "subview" and encapsulate it in its own nib file with it's own view controller, therefore I end up having nested view controllers.
In one of my apps I have a very complex table view cell, that has a subview. So I ended up having a hierarchy that goes like this: the tableview controller on the top level, the tableviewcell's controllers for each row and inside each of these a subviewcontroller for the subview inside each cell.
And everything works fine.
Pardon my english.