Different iphone android phones display parameters

Good morning, Is there a routines which give me the chance to understand what display parameters I need to use? Some android phones (specially last ones) has the three low button on the display, so when I create a tabbar, I cannot use it, since the control of low part of the phone is of three buttons.
Any help or hints would be appreciated.
Regards.
Alex

I also wanna know about it.