F2L — Open Source Messaging App

Lock your phone by closing the flap. No need to press the lock button anymore. If you do not have a flap cover, then merely putting the mobile into your pocket will lock the screen. Also you can specify to disable the app while a call is in progress. Time can be set for which the app will remain disabled once you unlock the screen. This avoids unwanted locking. By switching off the screen you save the battery, too.