The following five properties help you to achieve multiple resolution screens in android:
Screen size – Screen sizes are divided into four generalized sizes: small, normal, large, and extra-large.
Screen density – Screen densities are also divided into four generalized densities: low, medium, high, and extra-high.
Orientation – When user rotates the device the orientation of the device also gets changed.
Resolution – The total number of physical pixels on a screen.
Density – independent pixel (dp) – Provides you a density-independent way to define your layouts.