[Android] How to prevent the background from turning on again

I'm making a simple application with Android. With an application that returns to the background It is an application that repeats raising the number 1 after 10 seconds, changes the textview to that value, and turns off when it reaches 160.

I used timer and timerTask After you start the app, press the home button to return to the background After 10 seconds, the number 1 increases and the application displayed in textview turns on again.

I want to make sure that it doesn't turn on again I don't know what to do. It's my first time in the background, so I don't think I have a clue.

Please give us some advice.