How do I checkout an old git commit in Android Studio?

A git repository contains the all history at all time. So when you are cloning a repository, you are cloning it with its full history, and then, you can make a branch from whatever commit you want:

$ git checkout -b aNewBranch SHA1

with SHA1 representing the commit id from which you want to proceed.

If you want to checkout commit using Android Studio (or other IntelliJ IDEA based IDE) just go toVersion Control view (alt+9) and click the Log tab. Type your commit hash in Filter input, right-click on the commit entry and click the Checkout Revision option.

What's more, if you want to work with a command line, simply use git from command line. I'm working with Git using only command line and nothing wrong happend yet. The only thing that you have to remember is to wait for reindexing end.