Figure 1: Structure of the Android OS 5
Figure 2: Activity Life Cycle 10
Introduction
Android is a mobile operating system developed by Google based on the Linux kernel. Android is mainly designed for smartphone devices which implement a touch screen input interface. It has also been developed for other devices such as tablet computers, smart watches (Android Wear) and cars (Android Auto.)
Android is known for its OS touch inputs that correspond to real world actions such as tapping, swiping, pinching and reverse pinching.
Android is the most popular mobile operating system, competing with IOS for apple devices and Windows Phone. A developer survey conducted in April–May 2013 found that 71% of mobile developers develop for Android
Android Source code is released by Google under the open source licenses though most Android devices ship with a combination of open source software and proprietary software developed and licensed by Google. The open source nature of Android has enabled many to create and distribute their own modified version of the OS through the Android Open Source Project (ASOP). CyanogenMod is the most widely used community firmware.
Unlike other mobile operating systems, Android is written in Java and is run on virtual machines. Android features the Dalvik Runtime Machine and Android Runtime in newer versions which executes its own bytecode. Dalvik is a core component and all Android user applications and the application framework are written in Java and executed in Dalvik.
The development of Android takes place quickly with a new version being released every few months. Android release numerous updates that incrementally improve the operating system adding new features and fixing bugs in older releases. Each major release is released under the name of a dessert or sugary treat. The first version of Android was released in 2008, named cup cake and the versions to follow are Donut, Éclair, Froyo, Gingerbread, HoneyComb, Icecream Sandwich, Jelly Bean, KitKat and the latest, Lollipop.
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