android - CoutDownTimer inside a fragment -

i'm trying make android app has many selectable countdown timers. created app has main activity , uses several fragments load different countdown timers. i'm using navigation drawer , each menu item loads different fragment (the layout of every fragment textview , button @ moment).

should put countdowntimer code inside each fragment? 1 fragment have timer of 30 seconds, 1 has 60 , 90. examples found online work if put them inside main activity (if i'm not using fragments).