MIT App Inventor upgrade coming next Monday – the upgrade will support apps running on devices with different size screens, such as a smart phone versus a tablet.
There’s one important rule when using App Inventor to create apps with responsive design:
Specify widths and heights of components as percentages of the screen width and height, rather than as fixed numbers of pixels.
For example, to make a button whose width is half the screen width, set the button’s width to be 50 percent rather than setting it to a specific number of pixels.
Please see the link for details on this upcoming change.
Apps written in Java and the Android SDK have access to additional methods of creating flexible design layouts, or even multiple layouts, for different screen sizes.