How to Register New File Type Association with MP3

That window is just how you want Android studio to open the file so you can visualize/listen to the file. It does not affect how the file is handled by android at all.

Since Android Studio does not have a media player, I suggest you to select Open matching files in associated application That will launch your default music player and play that mp3.

Note: remember that all the files under res should ONLY contain lowercase letters, numbers and underscores. If you have your mp3 with the wrong name conditions will not compile.

I decided to select Text files. This was a bad idea since opening the file results in encoded garbage output to the screen.

With help from this page. I went back to File -> Settings -> File Types -> Text files and removed *.mp3 from the Registered Patterns by clicking the red minus sign.

See this image:

After this I clicked OK and re-synced the project with gradle. When this screen popped up again. I selected Open matching files in associated application. Now I do not get this pop-up and the mp3 opens in Windows Media Player if I double-click it.

This may not be an answer, but hope it'd be helpful to know that on Linux Mint Rebecca (based on Ubuntu 14.04), the problem is not reproduced.

1. Select File -> Settings -> File Types -> Files Opened In Associated Applications
2. Click on the + sign
3. Add "*.mp3"
4. (If you have previously incorrectly associated "*.mp3" with something else, then Android Studio warns you and allows you to delete the old association)
5. Click OK

It does not matter how you want to use MP3 files in your project afterwards. Android Studio now knows how to open them in case you click on them.