when i drag down the status bar while my app is running , everything goes blank and black screen appears. When the status bar goes back up there is still blank screen and when i touch the screen the views reappear. This only happens with micromax phone having android version 4.2.2. My activity has fragment activity. Same issues arises with different app also on this phone but when the status bar goes back to top their view comes back. I guess this is happening only the app with fragment activity.
It seems this problem is hardware specific.I think your phone processor is slow or has small ram in size. Clean some amount of RAM and check it again.