I\'m pretty new with Android programming, started a few weeks ago. Stackoverflow it\'s my new best fried since android day 1. For the 1st time, I would like to actually ask for
Here is a bit up to date answer to this question.
That bar is officially referred to as "navigation" bar. You can read answers to the same question over here : Android tablet navigation bar won't hide. In short - you need to root the device(s) and install BusyBox and HideBar.
The method is not too difficult, but it involves some risk of bricking your device and getting the installation of BusyBox wrong, which could get things a bit tricky, although is very unlikely to loose you any information. Also, you could get into a stalemate with your application where you can't restore the visibility of the bar - for example if 1 your GUI doesn't provide a close option, 2 your app start automatically on start-up, 3 HideBar doesn"t allow any way of re-displaying the navigation bar and 4 HideBar hids the navigation bar on startup.
Happy hacking ;)