The System bar’s Navigation buttons make it easy to quickly switch among Android apps.
In some media apps, the System bar controls are replaced by dim dots when you’re watching a movie, slide show, and so on, so you can better enjoy them without the distraction of the System bar. You can touch a dot as it if were the control it stands for, or touch a blank area of the System bar to restore it to full view.
|Back||Opens the previous screen you were working in. If the onscreen keyboard is open, the button changes to a down arrow and touching it closes the keyboard.|
|Home||Opens Home. If you’re viewing a left or right Home screen, opens the central Home screen.|
|Recent apps||Opens a list of thumbnail images of apps you’ve worked with recently; touch an app to open it.|
|Legacy||Opens the options menu for applications designed for previous versions of Android.|