Introduce Picture in Picture

[zigavehovec]

Description

This PR introduces Picture in Picture handling on Android including a sample usage.

Prework PRs:
#85
#86

Changes

• Add and use the FlutterPictureInPictureHandler
• Relay PiP related events
• Basic PiP sample

Tests

Checklist (for PR submitters and reviewers)

• 🗒 CHANGELOG.md entry for new/changed features, bug fixes or important code changes
• 🧪 Tests added and/or updated
• 📢 New public API is fully documented

[strangesource]

Nice work!

[strangesource]

NIT: could be a top level function in the file to make it clear that it does not need any state from the view.

[zigavehovec]

4f1efd2

[hawk23]

Nice work 💪

• I see that the PictureInPictureAvailabilityChanged event is not implemented for Flutter. As it's Android only, do you think it would make sense to expose it?
• As discussed on Slack, when _player.loadSourceConfig(_sourceConfig); is commented out in the PiP sample (no source loaded into the player), PiP does not work anymore on my personal Android device. The floating window does not appear and the player view just goes to Fullscreen mode.

[zigavehovec]

I see that the PictureInPictureAvailabilityChanged event is not implemented for Flutter. As it's Android only, do you think it would make sense to expose it?

I actually missed this event. I'll create a follow up ticket and we can tackle this in another PR 🙂

As discussed on Slack, when _player.loadSourceConfig(_sourceConfig); is commented out in the PiP sample (no source loaded into the player), PiP does not work anymore on my personal Android device. The floating window does not appear and the player view just goes to Fullscreen mode.

I looked into this and found some limitation in the native SDK DefaultPictureInPictureHandler. We discussed it with @strangesource and decided for a workaround until we improve the situation on the native side. edce49e