What is Android?
Android is a mobile operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen mobile devices such as smartphones and tablets. Now, it is used in TVs, Cars, Watches, etc.
Android history
- Google acquired a company Android Inc. in 2005 to start the development of the Android Platform. In late 2007, A group of Industry leaders came together around the Android platform and created an Open Handset Alliance (OHA).
- The First Android SDK was issued on November 5, 2007, by google
- In September 2008, T-mobile company announced its first Android platform-powered mobile: T-Mobile G1
- In October 2008, Google made the source code of the Android operating system open source under Apache open Source license
Android Architecture
Applications layer
It provides a set of core applications such as Email, SMS program, Calendar, Maps, Browser, Contacts, etc.
All applications can be written in either Java or Kotlin language.
Applications Framework layer
Almost all of the applications are built upon the classes provided by this layer. Some classes for example are Activity Manager, Power Manager, Alarm Manager, Device Policy Manager, VolumeInfo, and many more.
Applications are able to call the code of the framework layer using the Virtual machine known as ART (Android Runtime).
Android Libraries
Android Libraries include a set of C/C++ libraries which is used by classes of the Android framework. Functionalities provided by this layer are exposed to App developers using the Framework classes.
Some examples are
- Media libraries to play audio video
- Graphics libraries to render graphical objects and animations.
- SQL libraries to store data persistently
Android Runtime (ART)
Provides most of the functionalities provided by the Core Java libraries
It provides APIs for
- Data structures (Collections)
- File IO and Access
- Network Access
- Utilities
- Graphics
For more detailed info: AOSP Architecture