SlidingOutActivity is an Activity whose Content View is like a drawer which can be slid  right or left to show the Activity below it or to close itself. If you slide it to the right NO more than half of the screen width, you can see the the Activity below it, and it will bounce back after you release it. If you  slide it to the right more than half of the screen width, it will slide out and close the Activity after you release it.