I need to know the screen sizes of android devices to support multiple screen sizes application.
Answer
Look at this table: http://developer.android.com/guide/practices/screens_support.html#testing
You can use the pie chart here to have an idea of relative screen size usage: http://developer.android.com/resources/dashboard/screens.html
For a list of screen sizes, resolutions and dpi values, take a look at: http://en.wikipedia.org/wiki/List_of_displays_by_pixel_density
To calculate the real dpi value, check here: http://en.wikipedia.org/wiki/Pixel_density#Calculation_of_monitor_PPI