Is thread pausing of any one of two concurrent processes possible?like if facebook and twitter both are open but while using twitter, facebook thread can pause?

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Java

Mobile

Android

Hello all,I am developing phone checking app that will notify user about total mobile usage in a day, its an android app.
One of my biggest confusion is to calculate the usage of any app only when user directly interact with it like notifications of Facebook keeps on coming even user is using any other app,Is it possible that while using any other app like viber,twitter etc Facebook thread can be paused?(so that only relevant app usage count,one process can be handled by other)
If so what are the API and coding interfaces for that?
please help me in this complexity and thanks in advance for ur coordination.