The question you have asked involves a larger implementation with code.
-
Use ExoPlayer to play videos in android. You can learn it from this CodeLab and also check this for more information.
-
From your question i understand there is a cardView and when you press it, a video show play in another activity. So for this you need to know how to use Intents in android. Intents help in passing data(such as a video url) from one activity to another.
-
Also check this project which uses ExoPlayer to play videos from internet with URL.
4
solved How can i play a video in full screen in another activity on clicking a card view [closed]