Auto-rotating Tab Bars on the iPhone

This post is a quick summary of what's needed to get a tab bar (like the one in the Clock application) to switch from portrait to landscape when the user rotates their phone. Accelerometer goodness, yum!

The process is easy, but it has a couple of pitfalls. Here are the steps:

1. You have to override shouldAutorotateToInterfaceOrientation: in the view controllers for all the views in the tab bar. If a view controller's shouldAutorotateToInterfaceOrientation: returns NO, then the tab bar will not rotate, even if the view is hidden at the time of the rotation.
   
2. You should not override the tab bar controller's version of shouldAutorotateToInterfaceOrientation:
   
3. For regular views in the tab bar add the code below to viewDidLoad. If you skip this, your view will not resize when the phone is rotated while it's selected. However, it will resize when the user transitions to it from another view.
   
   
4. Make sure the controls on your regular views respond to changes in view size. If you're using Interface Builder's springs and struts, you can test the views right in IB, using the arrow at the right of the views' title bars.

Acknowledgements: I used the knowledge in some forum posts that Google revealed to me, together with some testing.

I hope you found this useful. If you have more tips, please post them in the comments, and I'll edit the posting accordingly, so others can have an easier time finding this information.