I read android documentation about layout designing. But yet I have a question about layout designing. How do I can design only a layout for all screens size? I want have multiple buttons in my application and but when I test my application in my android device that is Three-inch, as a result , one of buttons can not be seen. My application is not advanced and it has only multiple buttons for a few operations.
Check the following links. This will clear up all your confusions,
Supporting Different Screen Sizes
Supporting Different Densities