Android :: Activity Being Fired Off Too Many Times

Our app starts out with a tab activity. But, before the user can get into the tab activity to do work, we have to check to see if they're logged in. This login is required for all activities within the tab activity. So, instead of having this security check within all the activities, we created our own abstract "activity" and have the tab activities extending our custom activity. Our "security check" (just see if they have a login key and login token in Preferences) is put within the onResume() of the Abstract activity. If either of these checks come back false, we fire off the login activity and use dialog's within that screen.

(We're doing this because we don't want the user to be able to see the data on the tabs if they're not logged in, so this login activity is a black background with dialogs for username/password). The issue is, the onResume() of the abstract activity is being called numerous times, and starts the Login Activity multiple times. We've tried setting the "singleInstance" and singleTask flags on the xml for the login activity, but the activity ends up calling onActivityResult before it is even displayed on the screen.