What is an Android ?

Android is a mobile operating system developed by Google, based on a modified version of the Linux kernel and other open source software and designed primarily for touchscreen mobile devices such as smartphones and tablets. In addition, Google has further developed Android TV for televisions, Android Auto for cars, and Wear OS for wrist watches, each with a specialized user interface. Variants of Android are also used on game consoles, digital cameras, PCs and other electronics.
Initially developed by Android Inc., which Google bought in 2005, Android was unveiled in 2007, with the first commercial Android device launched in September 2008. The operating system has since gone through multiple major releases, with the current version being 9.0 "Pie", released in August 2018. The core Android source code is known as Android Open Source Project (AOSP), and is primarily licensed under the Apache License.

Android is also associated with a suite of proprietary software developed by Google, including core apps for services such as Gmail and Google Search, as well as the application store and digital distribution platform Google Play, and associated development platform. These apps are licensed by manufacturers of Android devices certified under standards imposed by Google, but AOSP has been used as the basis of competing Android ecosystems, such as Amazon.com's Fire OS, which use their own equivalents to the Google Mobile Services.

Android has been the best-selling OS worldwide on smartphones since 2011 and on tablets since 2013. As of May 2017, it has over two billion monthly active users, the largest installed base of any operating system, and as of June 2018, the Google Play store features over 3.3 million apps.
Android is an open source and Linux-based Operating System for mobile devices such as smartphones and tablet computers. Android was developed by the Open Handset Alliance, led by Google, and other companies.

Android offers a unified approach to application development for mobile devices which means developers need to develop only for Android, and their applications should be able to run on different devices powered by Android.

The first beta version of the Android Software Development Kit (SDK) was released by Google in 2007, whereas the first commercial version, Android 1.0, was released in September 2008.

On June 27, 2012, at the Google I/O conference, Google announced the next Android version, 4.1 Jelly Bean. Jelly Bean is an incremental update, with the primary aim of improving the user interface, both in terms of functionality and performance.
The source code for Android is available under free and open source software licenses. Google publishes most of the code under the Apache License version 2.0 and the rest, Linux kernel changes, under the GNU General Public License version 2.
Android Inc. was founded in Palo Alto, California, in October 2003 by Andy Rubin, Rich Miner, Nick Sears, and Chris White. Rubin described the Android project as "tremendous potential in developing smarter mobile devices that are more aware of its owner's location and preferences". The early intentions of the company were to develop an advanced operating system for digital cameras, and this was the basis of its pitch to investors in April 2004. The company then decided that the market for cameras was not large enough for its goals, and by five months later it had diverted its efforts and was pitching Android as a handset operating system that would rival Symbian and Microsoft Windows Mobile.
Rubin had difficulty attracting investors early on, and Android was facing eviction from its office space. Steve Perlman, a close friend of Rubin, brought him $10,000 in cash in an envelope, and shortly thereafter wired an undisclosed amount as seed funding. Perlman refused a stake in the company, and has stated "I did it because I believed in the thing, and I wanted to help Andy.
In July 2005,Google acquired Android Inc. for at least $50 million. Its key employees, including Rubin, Miner and White, joined Google as part of the acquisition. Not much was known about the secretive Android at the time, with the company having provided few details other than that it was making software for mobile phones.At Google, the team led by Rubin developed a mobile device platform powered by the Linux kernel. Google marketed the platform to handset makers and carriers on the promise of providing a flexible, upgradeable system.Google had "lined up a series of hardware components and software partners and signaled to carriers that it was open to various degrees of cooperation"
Speculation about Google's intention to enter the mobile communications market continued to build through December 2006.An early prototype had a close resemblance to a BlackBerry phone, with no touchscreen and a physical QWERTY keyboard, but the arrival of 2007's Apple iPhone meant that Android "had to go back to the drawing board".Google later changed its Android specification documents to state that "Touchscreens will be supported", although "the Product was designed with the presence of discrete physical buttons as an assumption, therefore a touchscreen cannot completely replace physical buttons".By 2008, both Nokia and BlackBerry announced touch-based smartphones to rival the iPhone 3G, and Android's focus eventually switched to just touchscreens.

The first commercially available smartphone running Android was the HTC Dream, also known as T-Mobile G1, announced on September 23, 2008.



On November 5, 2007, the Open Handset Alliance, a consortium of technology companies including Google, device manufacturers such as HTC, Motorola and Samsung, wireless carriers such as Sprint and T-Mobile, and chipset makers such as Qualcomm and Texas Instruments, unveiled itself, with a goal to develop "the first truly open and comprehensive platform for mobile devices". Within a year, the Open Handset Alliance faced two other open source competitors, the Symbian Foundation and the LiMo Foundation, the latter also developing a Linux-based mobile operating system like Google. In September 2007, InformationWeek covered an Evalueserve study reporting that Google had filed several patent applications in the area of mobile telephony.
Since 2008, Android has seen numerous updates which have incrementally improved the operating system, adding new features and fixing bugs in previous releases. Each major release is named in alphabetical order after a dessert or sugary treat, with the first few Android versions being called "Cupcake", "Donut", "Eclair", and "Froyo", in that order. During its announcement of Android KitKat in 2013, Google explained that "Since these devices make our lives so sweet, each Android version is named after a dessert", although a Google spokesperson told CNN in an interview that "It’s kind of like an internal team thing, and we prefer to be a little bit — how should I say — a bit inscrutable in the matter, I’ll say"

Android Application


Android Applications Android applications are usually developed in the Java language using the Android Software Development Kit. Once developed, Android applications can be packaged easily and sold out either through a store such as Google Play or the Amazon Appstore. Android 16

Android powers hundreds of millions of mobile devices in more than 190 countries around the world. It's the largest installed base of any mobile platform and is growing fast. Every day more than 1 million new Android devices are activated worldwide.

This tutorial has been written with an aim to teach you how to develop and package Android application. We will start from environment setup for Android application programming and then drill down to look into various aspects of Android applications

Various Versions of Android and API Level


Alpha – In this( Android 1.0) was the first versions of Android operating System by Google. It has basic functionality with a simple browser and other Google apps like Gmail, Maps and YouTube.
Beta – Later on with Android 1.1 few more functionality added, the API changes from Level 1 in Android 1.0 to Level 2. It supports attachment with MMS.
Cupcake – Cupcake was Android second version with new features as well as the Android framework API updated. It was Android 1.5 with on Screen Keyboard , Bluetooth and Updated UI for applications.
Donut – It was Android 1.6 nicknamed as DONUT. It added support for CDMA , additional screen sizes, talk to speech engine and battery indicator.
Eclair – Android 2.0-2.1 as like other versions this also come up with a nickname as ECLAIR and lot more functions & features. It come up with Bluetooth 2.1 , live wallpaper, HTML 5 support, ability to search sms & mms, flash support, digital zoom and more camera features
Froyo – Android version 2.2-2.2.3 introduced with USB tethering & WiFi hotspot functionality and apps can now be installed on memory card. Support Adobe flash, increased speed and performance of applications with new features.
Gingerbread – Gingerbread (Android 2.3-2.3.7) introduced with updated User Interface which provide more ease to use. Features are like sensors, multiple cameras(Front & back), virtual keyboard, better text suggestion, voice input capability and press hold copy paste capability. Honeycomb – This Android platform Honeycomb was designed for large screens like tablets so interface elements like virtual keyboard optimized for bigger screen. Home screen is optimized, tabs are introduced in browser with additional incognito mode and video chat & Gtalk is supported.
Ice Cream Sandwich –Ice Cream sandwich come in 2011 bringing all new look. It gives more ease to user like user can quickly swipe to close the apps, new gallery layout and built in photo editor.
Jelly Bean – Google made Operating System more responsive with Jelly Bean and introduces file sharing with Android Beam. Restricted profile, Dial Pad complete, supported other languages like Hindi, changed camera UI.
KitKat – Kitkat come up in 2013 with API Level 19. It has wireless printing capability, new dailer id, chrome webview and screen recording.
Lollipop – Android version 5.0-5.1.1 come up with improved RAM and battery management. Further restyling through Material design, no interrupts feature, unlock phone through Bluetooth trusted devices, print previews and smart lock feature.
Marshmallow – Marshmallow was released in year 2015, come up with smarter battery and doze mode (it prevents certain task from running if the phone being setting idle), Now On Tap, better privacy settings, easier to upgrade phone, Fingerprint sensor and built in visual voice mail.
Nougat – Android Nougat was made official in 2016 with updated emoji, 72 newly added, multi window view (switch between apps with double tap), smarter battery with data saver mode, more secured and high quality virtual reality with new dimensions.