Can I use two xibs with one viewcontroller - re: porting to iPhone 5

Question

I just submitted my first app to the app store (yay it was just approved!). I now want to update it to work with (look nicer on) the larger iPhone 5 screen. I don't intend to change anything other than to change the layout a bit for the larger screen.

NOTE: I don't want to have my current xib stretched.

Is it possible to create two xib files (ie: copy my current xib file for the main screen) and hook them both into the view controller and have it so that when the app launches, the app detects if there is an iPhone 5 screen or an earlier screen. Then, depending on which device it is, show the user a different screen.

I intend for underlying app to remain the same. All I want is to present a slightly different (taller) screen for iPhone 5 users with a few buttons/items moved around for the new layout. I otherwise won't be adding or removing anything from the interface.

This SO question/answer shows how to switch between an iPhone or iPad view. So to does this one. Both are helpful but I don't know how to modify this for the circumstance where the user is using an iPhone 5 with a larger screen or an iPhone 4S and below. Also, they assume two view controllers. I only want ONE view controller since absolutely NOTHING in the view controller logic changes - only the placement of the objects on the screen change and that is all done in the XIB.

I should think the answer should be that the view controller iteslf assesses what device it is running on then presents the appropriate xib? Yes? No?

If so, how would I go about this?

Answer 1

[Revised with Complete Answer on : Oct 7, 2012]

After significant research I found the answer, partly on this SO page (which shows how to detect which iPhone version your app is running on) and partly this SO page (showing how to have two xib's share the same 'File's Owner'. The final piece of the puzzle (loading separate xib's via the loadNibNamed: method) I found in chapter 10 of The Big Nerd Ranch's excellent iOS Programming text. Here's how:

1. Create a second xib (File, New..., File, select 'User Interface', select 'Empty' and save it. This creates the new xib. In the example below, my classic xib (for 3.5" iPhones) was named TipMainViewController.xib. I saved the new iPhone 5 xib with the name 'TipMainViewController-5.xib'

2. Make that new xib's 'File's Owner' the same ViewController as your existing xib. To do this, in the new xib file, select 'File's Owners'. Then in the 'Identity Inspector' select the existing View Controller as the Custom Class. In my case I selected 'TipMainViewController'.

3. Drag a new UIView onto the new xib's empty canvas. In the new UIView's attribute inspector set the 'Size' attribute to 'Retina 4 Full Screen'

4. Select all the contents in the existing 'Classic' 3.5" xib - eg: all your controls, buttons, selectors, labels etc. Copy them and paste them into the new iPhone 5 xib. Resize/move etc. them to optimize for the iPhone's 4" display.

5. Make all the connections to/from File's Owner as you did when you created your original xib.

6. Finally, in the 'viewDidLoad' method of your 'single' ViewController, insert the following logic (using your nib/xib names of course):

   - (void)loadView
   {
       [super viewDidLoad];
       if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
       {
           CGSize result = [[UIScreen mainScreen] bounds].size;
           if(result.height == 480)
           {
             // iPhone Classic
             [[NSBundle mainBundle] loadNibNamed:@"TipMainViewController" owner:self options:nil];
           }
           if(result.height == 568)
           {
             // iPhone 5
             [[NSBundle mainBundle] loadNibNamed:@"TipMainViewController-5" owner:self options:nil];
           }
       }
   }