How can I check if the user tabs into my game

If someone is playing and switches out of the app, I need to know when they re enter the game. I’m hoping someone know a cross platform method of doing this. On my phone, if you leave the game and then open it again, I’d like to update my unity UI Text components. They disappear in that situation, but accessing them seems to bring them. I want to do it once, when the player opens the shop. I don’t want to update the Text every frame.

Detecting when applicationDidBecomeActive In Unity