How Android OS works in smartphones?

Android OS Working in Mobile Platform

Android is a lightweight mobile OS made for low SOC architecture, to know how android works in smartphones you can start with top level 5 layered diagram below. Every android distribution consist of these layers namely Application, Framework, Libraries, Runtime, Kernel.

Starting at the bottom is the Linux Kernel. Android uses Linux for its device drivers, memory management, process management, and networking. However you will never be programming to this layer directly.

The next level up contains the Android native libraries. They are all written in C/C++ internally, but you'll be calling them through Java interfaces. In this layer you can find the Surface Manager (for compositing windows), 2D and 3D graphics, Media codecs (MPEG-4, H.264, MP3, etc.), the SQL database (SQLite), and a native web browser engine (WebKit).

Next is the Android runtime, including the Dalvik Virtual Machine. Dalvik runs Dex files, which are converted at compile time from standard class and jar files. Dex files are more compact and efficient than class files, an important consideration for the limited memory and battery powered devices that Android targets.