How can I overlay a "play button" over a VR Video?

I want to add a giant white play button on top of the video for both VR and non-VR modes of my VrVideoView. How do I tell when I'm in VR view?

I'm using com.google.vr.sdk.widgets.video.VrVideoView to handle playing the video both with and without the headset on.

My thought process so far:

I have no way to check/bind to when someone goes in and out of VR mode, so I don't know when to add one versus two play buttons over the video.
So given the above, I've thought about modifying the video programmatically to achieve this. Is that my only choice?

Solution

We ended up having the video edited to add a play button to the first frame.

It's not possible to be notified of when the user enters/exits VR mode.

Here's why: The Android Google Cardboard VR SDK is built to be accessible for easy integration in content-viewing apps. It is not built to be used in a custom-VR video viewing application. Here's a thread on Github about the topic

Due to the limitations above, we very quickly rewrote the application in Unity (still using Cardboard SDK)