Introducing Android Free and Open Source

Android is an open source platform. Neither developers nor handset manufacturers pay royalties or license fees to develop for the platform. The underlying operating system of Android is licensed under GNU General Public License Version 2 (GPLv2), a strong “copyleft” license where any third-party improvements must continue to fall under the open source licensing agreement terms.The Android framework is distributed under the Apache Software License (ASL/Apache2), which allows for the distribution of both open- and closed-source derivations of the source code. Commercial developers (handset manufacturers especially) can choose to enhance the platform without having to provide their improvements to the open source community. Instead, developers can profit from enhancements such as handset-specific improvements and redistribute their work under whatever licensing they want. Android application developers have the ability to distribute their applications under whatever licensing scheme they prefer. Developers can write open source freeware or traditional licensed applications for profit and everything in between. Familiar and Inexpensive Development Tools Unlike some proprietary platforms that require developer registration fees, vetting, and expensive compilers, there are no upfront costs to developing Android applications. Freely Available Software Development Kit The Android SDK and tools are freely available. Developers can download the Android SDK from the Android website after agreeing to the terms of the Android Software Development Kit License Agreement.

Familiar Language, Familiar Development Environments

Developers have several choices when it comes to integrated development environments (IDEs). Many developers choose the popular and freely available Eclipse IDE to design and develop Android applications. Eclipse is the most popular IDE for Android development, and there is an Android plug-in available for facilitating Android development.Android applications can be developed on the following operating systems: n Windows XP (32-bit) or Vista (32-bit or 64-bit) n Mac OS X 10.5.8 or later (x86 only) n Linux (tested on Linux Ubuntu 8.04 LTS, Hardy Heron) Reasonable Learning Curve for Developers Android applications are written in a well-respected programming language: Java. The Android application framework includes traditional programming constructs, such as threads and processes and specially designed data structures to encapsulate objects commonly used in mobile applications. Developers can rely on familiar class libraries, such as java.net and java.text. Specialty libraries for tasks such as graphics and database Android Platform Differences 21 management are implemented using well-defined open standards such as OpenGL Embedded Systems (OpenGL ES) or SQLite.

Enabling Development of Powerful Applications

In the past, handset manufacturers often established special relationships with trusted third-party software developers (OEM/ODM relationships).This elite group of software developers wrote native applications, such as messaging and web browsers, which shipped on the handset as part of the phone’s core feature set.To design these applications, the manufacturer would grant the developer privileged inside access and knowledge of a handset’s internal software framework and firmware. On the Android platform, there is no distinction between native and third-party applications, enabling healthy competition among application developers.All Android applications use the same libraries.Android applications have unprecedented access to the underlying hardware, allowing developers to write much more powerful applications.Applications can be extended or replaced altogether. For example,Android developers are now free to design email clients tailored to specific email servers, such as Microsoft Exchange or Lotus Notes. Rich, Secure Application Integration Recall from the bat story I previously shared that I accessed a variety of phone applications in the course of a few moments: text messaging, phone dialer, camera, email, picture messaging, and the browser. Each was a separate application running on the phone— some built-in and some purchased. Each had its own unique user interface. None were truly integrated. Not so with Android. One of the Android platform’s most compelling and innovative features is well-designed application integration.Android provides all the tools necessary to build a better “bat trap,” if you will, by allowing developers to write applications that seamlessly leverage core functionality such as web browsing, mapping, contact management, and messaging.Applications can also become content providers and share their data among each other in a secure fashion. Platforms such as Symbian have suffered from setbacks due to malware.Android’s vigorous application security model helps protect the user and the system from malicious software.

No Costly Obstacles to Publication

Android applications have none of the costly and time-intensive testing and certification programs required by other platforms such as BREW and Symbian. 22 Chapter 1 Introducing Android

A “Free Market” for Applications

Android developers are free to choose any kind of revenue model they want.They can develop freeware, shareware, or trial-ware applications, ad-driven, and paid applications. Android was designed to fundamentally change the rules about what kind of wireless applications could be developed. In the past, developers faced many restrictions that had little to do with the application functionality or features: n Store limitations on the number of competing applications of a given type n Store limitations on pricing, revenue models, and royalties n Operator unwillingness to provide applications for smaller demographics With Android, developers can write and successfully publish any kind of application they want. Developers can tailor applications to small demographics, instead of just large-scale money-making ones often insisted upon by mobile operators.Vertical market applications can be deployed to specific, targeted users. Because developers have a variety of application distribution mechanisms to choose from, they can pick the methods that work for them instead of being forced to play by others’ rules.Android developers can distribute their applications to users in a variety of ways: n Google developed the Android Market (see Figure 1.7), a generic Android application store with a revenue-sharing model. Figure 1.7 The Android market. n Handango.com added Android applications to its existing catalogue using their billing models and revenue-sharing model. n Developers can come up with their own delivery and payment mechanisms. Mobile operators are still free to develop their own application stores and enforce their own rules, but it will no longer be the only opportunity developers have to distribute their applications.

A New and Growing Platform

Android might be the next generation in mobile platforms, but the technology is still in its early stages. Early Android developers have had to deal with the typical roadblocks associated with a new platform: frequently revised SDKs, lack of good documentation, and market uncertainties. On the other hand, developers diving into Android development now benefit from the first-to-market competitive advantages we’ve seen on other platforms such as BREW The Android Platform 23 and Symbian. Early developers who give feedback are more likely to have an impact on the long-term design of the Android platform and what features will come in the next version of the SDK. Finally, the Android forum community is lively and friendly. Incentive programs, such as the ADC, have encouraged many new developers to dig into the platform. Each new version of the Android SDK has provided a number of substantial improvements to the platform. In recent revisions, the Android platform has received some muchneeded UI “polish,” both in terms of visual appeal and performance.Although most of these upgrades and improvements were welcome and necessary, new SDK versions often cause some upheaval within the Android developer community.A number of published applications have required retesting and resubmission to the Android Marketplace to conform to new SDK requirements, which are quickly rolled out to all Android phones in the field as a firmware upgrade, rendering older applications obsolete. Some older Android handsets are not capable of running the latest versions of the platform.This means that Android developers often need to target several different SDK versions to reach all users. Luckily, the Android development tools make this easier than ever.