Android : Log in to google play on another activity

My User is logging himself in on google play on my mainscreen with:

mGoogleApiClient.connect();

on second activity, when i call (isLoggedIn), I'm getting false, although he has logged in on my main page. If I'm calling

mGoogleApiClient.connect();

in the second activity, my app breaks.

how to do that he is also logged in on the second page?