 <p>No a handler is a separate object class and so one would not need to be defined if you were making an Activity.</p> <p><a href="http://developer.android.com/reference/android/app/Activity.html" rel="nofollow">Activity</a></p> <p>A handler would be used if you wanted to go do something in another thread/class and call back to the activity/ui.</p> <p><a href="http://developer.android.com/reference/android/os/Handler.html" rel="nofollow">Handler</a></p>