I want to position a UIView so it appears in the centre on both 3.5” and 4” Retina screens. What is the best way to do this? If I turn off all the Autosizing bars I would expect
Follow these steps for your XIB and you should be getting the correct resizing for your views:
For seamless iOS4 compatibility, start by setting the top view Size to Retina 3.5 size.
Remove the size parameter for the top view and set it to "none". You should now have a main view with the correct size but without a fixed set size option.
Turn on all autosizing vertically for the top view under the "Size inspector" tab.
For each of the subviews do the following
Save your changes. Check if you were successful with your autoresizing by selecting the top view and choose size: "Retina 4 Full Screen". When doing this, your view should look like your intended result.
Undo the change in 5 (so that the view in the xib has the 3.5 size again, but the Size option set to "None", save and run your app.
This works for iOS4 also, because the size of the view is already adapted for Retina 3.5 thus no autosizing is used for the older screen size.
In some occasions, it is not possible to get the exact right sizes/positioning for all the elements. In these cases you need to programmatically change the views sizes position for the 4" screen size.