For a situation when you know your application is temporarily grabbing focus from the current owner, but the user expects playback to go back to where it was once your application no longer requires audio focus.
Also for a temporary request, but also expresses that your application expects the device to not play anything else. This is typically used if you are doing audio recording or speech recognition, and don’t want for examples notifications to be played by the system during that time.
This focus request type is similar to AUDIOFOCUS_GAIN_TRANSIENT for the temporary aspect of the focus request, but it also expresses the fact during the time you own focus, you allow another application to keep playing at a reduced volume, “ducked”.
Expresses the fact that your application is now the sole source of audio that the user is listening to. The duration of the audio playback is unknown, and is possibly very long: after the user finishes interacting with your application, (s)he doesn’t expect another audio stream to resume.