WhatDPI

*What is "What DPI"?

What DPI is a simple tool for Android Developers/Designers to quickly find out the screen parameters.

*What "What DPI" will tell me?

Basically this app will show you:

Density

Screen Resolution in pixels

Density Factor

Resolution in dp

xdpi and ydpi

*What are those stuff means?

Density: Android is using ldpi mdpi hdpi xhdpi xxhdpi and tvdpi to represent the screen densities.
Screen Resolution in pixels: yeah, that's your device's resolution in pixels.
Density Factor: To do a conversion from pixel to dp, Android using the density factors, which differs from the screen density. mdpi is baseline screen density, so it has density factor 1.0, then hdpi is 1.5, then xhdpi is 2.0. So 1 pixel on xhdpi equals 1 * factor = 1 * 2 = 2 dp. So as 1.5 dp on hdpi and 1 dp on mdpi.