How Keep Android application active on screen timeout

You can only do this if the developer of the application has designed the app in this way. Android works differently than normal desktop applications do.

my concern is when i click a display button it  goes to another screen it runs for 20 sec, instead of staying in that screen it comes back to the original screen.

yes asking as a programmer

  on the click event of display i have written
10 down vote

I used:

getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

to disable the screen timeout,  but it is not working