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I made a project with MonoTouch 5. After upgrading to MonoTouch 6 my UIViewControllers are not auto-rotating anymore. These are hosted inside a tabviewcontroller. I get this warning:

ShouldAutorotateToInterfaceOrientation(MonoTouch.UIKit.UIInterfaceOrientation)' overrides obsolete member `MonoTouch.UIKit.UIViewController.ShouldAutorotateToInterfaceOrientation(MonoTouch.UIKit.UIInterfaceOrientation)'. Add the Obsolete attribute to ShouldAutorotateToInterfaceOrientation(MonoTouch.UIKit.UIInterfaceOrientation)' (CS0672)

But the method still gets called when I am debugging. The new ShouldAutorotate never gets called. Any ideas? Thanks!

poupou
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vbisbest
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  • And actually, its only when testing iOS 5.1. iOS 6.0 works as expected. How do you handle rotation for both? Thanks. – vbisbest Jan 25 '13 at 16:37

2 Answers2

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There can be a few reasons. One of them is that you should be (if not already) setting the RootViewController in your AppDelegate (another link here). That was not required before iOS6.

Another one is starting to use the new iOS6 API, without keeping a fallback for earlier iOS versions. That would match your comment, i.e. works on 6.0 but not on 5.1.

Note that since you're still targeting iOS 5.x you can safely ignore the obsolete warnings. iOS 6 introduced new API to handle rotation but it will automagically fallback to the old API to keep compatibility with existing applications.

That also means that if you start using the new (iOS6 only) API then you'll need to handle the old API yourself or rotation won't work with iOS 5.x.

Honestly I think that's a testing nightmare - you're better off letting iOS handle this and keep a single code path to handle rotation. That why I strongly suggest you to keep using the older API until your deployment target minimal version becomes iOS 6.0.

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poupou
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  • Ouch, ok. I guess no rotation for 5.x users then. Thanks for the details. – vbisbest Jan 25 '13 at 21:26
  • uho! I think you misunderstood me. You can get rotation working on **both** iOS 5.x and 6.0 by using the API available on iOS5 (i.e. do not use iOS6-only API). – poupou Jan 25 '13 at 21:38
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I had the same issue after upgrading and I got the answer to my problem over here. Here is the heart of the problem, quoted from the link:

Application windows are expected to have a root view controller at the end of application launch

So if previously like me you have this in your FinishedLaunching(UIApplication app) method in main.cs:

window.AddSubview(mainVC.View);

Replace it with this:

window.RootViewController = mainVC;

That's it! Happy days! Rotation works again. :) At least it solved the problem for me.

I don't know whether this small thing causing the application to go wrong is Apple's fault or Monotouch/Xamarin's fault, but I think that the Xamarin team should do something about this. Surely this is something that could be detected and corrected at compile time?

Anyway. Hope this information saves other people the hours that this issue has cost me!

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BruceHill
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