Android : Android Alert dialog based on if - else statement

I'm very new to Android programming and am a bit stuck.

I have a log in screen and a separate class for each of the alert dialogs ( both have OK and close buttons) .

Based on what kind of user logs in I need to display a certain alert ( ie: admin logs in , there is a popup with an "Administrator is now logged in. " ).

I have an if - else statement in my code for the log in activity and after parsing of a json object and deciding whether the user is normal or admin , when the Log in button is clicked the popup message must appear.

if ( member.isadmin() == 1 ) { 
// alertdialog for admin logged in 
}

else {
// alertdialog for user
}