Introduction to Android

Android is a Linux-based operating system, which makes it open source software distributed under the Apache License Agreement by Google Inc. Due to its open source nature, other phone vendors have started porting the Android operating system on their newly created phones, which contributed to a very varied smartphone market for consumers. Starting from the first version of Android, this operating system has gained a good level of maturity, making it more reliable, secure, and stable operating system for smartphones. Let's have a look on some popular versions of Android in the next section.

Android versions

Year by year, Android has increased its maturity level with each new version. Every version introduced new set of features from the user interface to customizations to flexibility to security. In terms of names, these versions are based on names of candy, chocolates, and other sweet stuff, such as Kitkat, Lollipop, and Marshmallow, but that's what makes Android a little more understandable to consumers and developers as well.

It is an interesting fact that the versions of Android are in alphabetical order. Starting off from Apple Pie 1.0 and then Banana Bread 1.1, it made its way towards Nougat with a completely coherent of alphabetical sequence maintaining the legacy.

The following table highlights the main features of the different Android versions with their API levels as well:

Android version	Version name	Main features	API level	Release month
1.0 G1	Banana Bread	GPS, Bluetooth, Multitasking, Google Services, Android Play Store	2	February 2008
1.5	Cupcake	Search Box, Revamped Android Play Store, Camera, Gestures	3	April 2009
1.6	Donut	Onscreen Keyboard, Home Screen Widgets, Folders	4	September 2009
2.0.x	Éclair	Multiple User Accounts, Flash Support, Zoom Feature, Bluetooth 2.1	5, 6, and 7	October 2009
2.2.x	Froyo	USB tethering, Hotspot support, Adobe Flash, Voice Dialling	8	May 2010
2.3.x	Gingerbread	New Copy/Paste, WebM, NFC, Front Camera	9, 10	December 2010
3.x	Honeycomb	3D Graphics, Redesigned UI, Video Chatting, Bluetooth tethering, 3G, 4G	11, 12, and 13	February 2011
4.0.x	Ice Cream Sandwich	Virtual buttons, Face Unlock, Native Camera Features, Face Detection, Android Beam, Wi-Fi Direct	14 and 15	October 2011
4.1 - 4.3	Jelly Bean	Expandable Notifications, Google Now	16, 17, and 18	July 2012
4.4	Kit Kat	Major Design Interface Update, Translucent Status bar, Immersive Mode, Wireless Printing	19 and 20	October 2013
5.0	Lollipop	Redesigned UI with Material, Lock Screen Notifications, Guest mode, Battery Saver mode	21	October 2014
6.0	Marshmellow	Fingerprint security support, Doze mode for battery saving, App standby mode, Enhanced App permission	23	October 5, 2015
7.0	Nougat	Multi window view, VR support	24, and 25	August 22, 2016

Table 1.1: Era of operating systems from Android Cupcake to Lollipop

The table only shows the changes made by Android operating system's developer, Google Inc. But due to Android's open source nature, other mobile manufacturing companies have also changed and introduced new features and modifications into Android. For example, Samsung has made a custom touch interface called TouchWiz, and HTC has made a custom user interface called HTC Sense. Similarly, Sony has introduced a custom user interface called TimeScape.

Figure 1.1 Latest Android phones launched in year 2014

Google Play - the market store for Android

After the introduction of smart phones, the concept of market store came to existence in software technology, which revolutionized the mobile development industry. A significant role was played by Google Play in that revolution of mobile apps and games. Google Play is the largest market store in smartphones, with more than 2.2 million Android apps, games, books, music, shows, and more. These apps and games have been downloaded more than 50 billion times up to this point, and that marks a huge milestone achieved by Google in just 8 years of Android. You can check out Google Play at http://play.google.com.

Google Music, Google Movies & TV, Google Books, and Google Magazines are available in only limited countries.

Figure 1.2 Google Play on an Android device