Allow backgroundVisible to be modified

[ceyhun-o]

The scenario is this:

As a user, I don't want to show any UI elements during an ad playback. At the moment, when hiding all controls during ad playback, the backgroundVisible is still active, and causes and animation on taps. It also doesn't seem to accept any color overrides (eg. to make it transparent as a workaround because of this logic:

android-ui/ui/src/main/java/com/theoplayer/android/ui/UIController.kt

Lines 188 to 190 in 54d17fa

	val background by animateColorAsState(
	label = "BackgroundAnimation",
	targetValue = color.copy(alpha = if (backgroundVisible) 0.5f else 0f),

background.mp4

This is due to a check we removed here: 225ccd5

We need to make the backgroundVisible adjustable so that:

• The users that want to show a UI during ad playback can still do so with the animation.
• The users that don’t want to show anything during ad playback, can avoid this grey overlay/animation.

[MattiasBuelens]

To be honest, I find it a bit user-hostile to not show any UI controls while playing an ad. Surely you should have a play/pause button somewhere, no? 😅

Anyway, I do agree that setting color = Color.Transparent should work. Right now, we're doing color.copy(alpha = ...) which unconditionally overrides the alpha value, even if it was set to 0. 🤔