Hello. I am creating an application helps to beat phone addiction and improve work productivity, similar to the Pomodoro Timer. I need my created timer to reset and stop if some other application is running, or for example only browsers, messengers and video players like youtube. Is it possible to implement this in the MIT App Inventor and in what way? Sorry for my English (Translator)
Here is an answer from Stackoverflow
You also could do a search there to get more ideas...
You could write your own App Inventor extension and create the functionality..
more information about how to create an extension see the App Inventor Extensions document however that will be more advanced and will require some Java skills...
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.