The following text was found on the AppCode basic web site.. This practice will definitely helps you to find the files using AppCode IDE within your project.
When working on your own project, you often know which file or class you want to open and edit. The fastest way to do this is to use Go to Class... (Cmd+O) or Go to File... (Cmd+Shift+O).
e.g
You can also find excluded project files as well.
Please check this for more details.