参考：http://stackoverflow.com/questions/20252180/how-to-find-string-in-project-in-android-studio
How to find string in project in Android Studio?
First of all, this IDEA has a nice "Find Usages" command. It can be found in the context menu, when the cursor is on some field, method, etc.
It's context-aware, and as far as I know, is the best way to find class, method or field usage.
Alternatively, you can use the
Edit > Find > Find in path…
dialog, which allows you to search the whole workspace.
Also in IDEA 13 there is an awesome "Search Everywhere" option, by default called by double Shift. It allows you to search in project, files, classes, settings, and so on.