What I would do is add all of your Android AOSP SDK files to a separate tagging file and then keep only your project files in the project directory -
Tools | Tag Files | Add Tag File -
Fill out the form (I would check generate references) and then hit OK. This will parse the SDK files and make them accessible under the Symbols tool window and also help with auto-completion and I also think it will help with the performance.
For the project files, do Project - Properties, make sure All Configurations is selected in "Settings For:" then select the Files tab and then press Add Tree on the right hand side to add your files.
Hope that helps!