3-button navigation is Android's oldest touchscreen-based navigation
+ system. It will remain supported for the foreseeable future to provide
+ accessibility for users unable to easily use the gestures. It's older than
+ 2-button navigation but isn't considered a legacy feature.
+
A large row across the bottom of the screen is reserved for navigation
buttons. The Back button is on the left, the
Home button is in the center and the Recent