Fix random NullPointerException when adding video player view

[Stypox]

What is it?

• Bugfix (user facing)
• Feature (user facing)
• Codebase improvement (dev facing)
• Meta improvement to the project (dev facing)

Description of the changes in your PR

Followup to #8170, bug reported by @opusforlife2. I don't know why the binding could be null when getView() returns a non-null value, unless the view is destroyed exactly in between new Handler().post() being called and the passed function being actually called, but anyway...

Fixes the following comments

• Refactor player and extract UI components #8170 (comment) Refactor player and extract UI components #8170 (comment)
• Tablet layout encountered after full screen video ends, despite Tablet mode being off #8646 (comment)

APK testing

The APK can be found by going to the "Checks" tab below the title. On the left pane, click on "CI", scroll down to "artifacts" and click "app" to download the zip file which contains the debug APK of this PR.

Due diligence

• I read the contribution guidelines.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

0.0% Coverage
0.0% Duplication

[opusforlife2]

I discovered something stupid :D

I tried the player-refactor APK again just to compare it with this PR. The bug didn't occur!

And then some testing led me to realise that the crash occurs only when the full screen button is tapped while the device is moving! So if the device stays still on a surface or you keep your hand still while holding it, the full screen button works properly. But if the accelerometer registers movement, there is a crash.

This bug is so strange that I think it must be CalyxOS-specific.

Anyway, this PR fixes this weird bug.

[Stypox]

Merging as it is such a simple change and opus said it is now fixed for him.

only when the full screen button is tapped while the device is moving

It kinda makes sense, since the fixed code has to do with adding the video player view (also) after layout changes, but strange nonetheless ;-)