Compatible devices MUST support dynamic orientation by applications to either portrait or landscape screen orientation. That is, the device must respect the application's request for a specific screen orientation. Device implementations MAY select either portrait or landscape orientation as the default.
There are some screen resolutions already defined in Android. They are: QVGA (240×320, low density, small screen) WQVGA (240×400, low density, normal screen) FWQVGA (240×432, low density, normal screen) HVGA (320×480, medium density, normal screen) WVGA800 (480×800, high density, normal screen) WVGA854 (480×854 high density, normal screen)
QVGA (Quarter Video Graphics Array)
QVGA (Quarter Video Graphics Array or Quarter VGA) is a type of resolution whose dimensions are 320×240 pixels. The QVGA display is normally found in devices such as mobile phones and PDAs. The display is also common on other hand-held devices such as game consoles.
Most of the time, the display is in the portrait layout as opposed to the landscape layout. They are also known as 240×320 displays because they are taller than they are wide. So why is it known as Quarter Video Graphics Array? It has this name because the display is 1/4th of the 640×480 resolution of the original IBM machine that had the VGA display. The original display was almost a de facto standard in the 1980s.
Wide QVGA or WQVGA is any display resolution having the same height in pixels as QVGA, but wider. This definition is consistent with other 'wide' versions of computer displays.Since QVGA is 320 pixels wide and 240 pixels high (aspect ratio of 4:3), the resolution of a WQVGA screen might be 384×240 (16:10 aspect ratio), 400×240 (5:3—such as the Nintendo 3DS screen or the maximum resolution in YouTube at 240p), 428×240 or 432×240 (~16:9 ratio).