Here’s a possibly-too-obvious tip for folks who are adapting older iOS and Mac UI from traditional “springs and struts” to Auto Layout: always make a copy of the nib content you are working on before you start hacking away.
Because Auto Layout requires you to flip the switch for e.g. a whole window at once, and because the various adjustments to frames you make while adapting to Auto Layout may affect views in unwanted and unexpected ways, it’s extremely convenient to have at hand the UI layout as it was before surgery, so to speak.
Sure, because everybody in their right mind these days uses version control software, it’s easy enough to check out a previous iteration of a xib file and open it up for comparison, but it’s become such a certainty that I will find value in the reference, I usually just make a redundant copy in the xib itself while I’m working:
1. Select the window element in Xcode’s Interface Builder.
2. Copy and paste to make a new copy.
3. Adjust the original’s Auto Layout information until satisfied.
4. Delete the copy.
Having the reference copy is very handy as well for trying to isolate layout behaviors to just specific parts for the UI. For example, a deeply nested view seems to behave unexpectedly and you can’t get the layout right. Copy just the original from your “backup window”, and paste the view in isolation. Now see if you can get the layout right in terms of itself, without respect to the larger window. This can help you figure out the “aha!” constraint that you need to go back and add to the “real window.”