How can I trigger an action when the mobile phone screen is turned off/locked?

Hi everyone! How you guys doing? :)

Let me clarify the problem:

I'm building a mobile app game, which many of the actions are based on real time, so when the App is suspended, I generate a timestamp that will be comapred with a new timestamp when the game is resumed, so I can get the "offline time".

It's working perfectly when I switch tabs on my phone, but NOT when I lock the screen! When I lock the screen, the game remains like "paused", and the timestamps are not generated.

So, is there any event option that I can use to trigger the 'screen locking'?

Thank you so much for reading this and helping me out! <3

You can simply generate these timestamps constantly, say, every second. And compare the time from the last timestamp, if it's more than a few seconds, the app has probably been suspended.

It's working perfectly when I switch tabs on my phone, but NOT when I lock the screen!

That should still trigger 'On suspended'. Are you saying it does not?