A typical video player always displays its controls and video content while it's
running; it can't operate in the background or without a UI. Therefore, it's
appropriate to build your app as a single activity containing the UI, a player,
a media session, and a media controller:
- Building a videoplayer activity
- How to create an activity that contains a media session and a media controller.
- Media session callbacks
- Describes how the media session callback methods manage the media session and other app components like notifications and broadcast receivers.