What is Android?

The original meaning of Android refers to the "robot", the name of the Open-source smartphone operating system based on Linux, published by U.S. search company Google on November 5, 2007. The platform is comprised of operating systems, middleware, and applications, claiming to be the first truly open and complete mobile software to be built for mobile terminals. It employs the architecture of the software stack (software stack), which is based on the Linux core, provides only basic functionality, and other applications are developed by the companies themselves, as part of programming in Java. In addition, to promote this technology, Google and the other dozens of mobile phone companies to establish an open mobile phone Alliance (Open Handset Alliance). Android is often rumored to be Google phone or gphone before it is made public. Most rumors suggest that Google is developing its own mobile phone product, rather than a software platform.

September 23, 2008, U.S. operator T-mobile USA in New York officially released the first Google mobile phone--t-mobile G1. The mobile phone for HTC Manufacturing, is the world's first mobile phone using the Android operating system, support WCDMA/HSPA Network, theoretical download rate of 7.2Mbps, and support Wi-Fi. T-mobile G1 officially on sale on October 22.

Android includes the operating system, middleware and applications-all the software needed for mobile phones, and there are no proprietary barriers that have previously hampered the innovation of the mobile industry. Google has developed Android with Open Handset Alliance, the OHA, which is comprised of more than 30 technology and wireless applications, including China Mobile, Motorola, Qualcomm, HTC and T-mobile. Through a deep partnership with operators, equipment manufacturers, developers and other parties involved, Google hopes to create an open ecosystem within the mobile industry with the help of a standardized, open mobile phone software platform.

Android, as an important part of Google's corporate strategy, will further advance the corporate goal of "providing everyone with information anytime, anywhere." Google's goal is to make mobile communications independent of devices and even platforms. For this purpose, Android will complement, rather than replace, Google's long-standing strategy for mobile development: to develop both attractive and engaging mobile services and to promote them through partnerships with handset manufacturers and mobile operators around the world.

An important feature of Android is that its application framework and GUI libraries are all implemented in the Java language. Inside Android, there is a Java virtual machine called Dalvik, which is interpreted by this virtual machine as a Java program. Applications in the Android platform must also be developed in the Java language. Online There are comments that Android's virtual machines use Apache's Harmony class library. The Harmony Class Library is an open source Java class Library developed by the Apache organization, published with Apache licenses. The Android application framework uses the Mash-up component model: The component (activity) registers its own functionality with the system, each component is required to use the services of other components to present its own requirements (intent), and the system determines the appropriate components in the registered component according to intent. The Android platform's API documentation is perfect.

It should be easy and enjoyable to develop application software based on Android platform. However, choosing the Android platform has the following issues:

Google currently only open the SDK, the Application software development interface, there is no open middleware source code.

In the absence of source code, Android can also be ported to a compatible development Board (the CPU kernel uses the ARMV5 instruction set), but cannot be used for actual products because it cannot be customized. Google is now not clear when to release the middleware source code. In fact, Google has not explicitly said will release the middleware source code. Google says Android is "the complete, open, and free mobile platform." In English, the word "free" can be interpreted as "free", or it can be interpreted as "freedom". How to explain it all lies in Google. I think Google is most interested in the application developers, that is, the hope that companies and individuals to learn its SDK, for its platform to develop application software. Google will certainly work with manufacturers to develop handsets that support the Android platform. But whether Google will fully open middleware code on the web is an unknown. If Google is fully open to the platform, then, like J2ME, companies will certainly add their own extensions to the platform, making the platforms not fully compatible. So Google is likely to use commercial tools to keep the Android platform consistent.

Android is a beautiful design, but it is still a practical test.

Using Java, Android can take advantage of Java platform Independence and reduce the difficulty of software development. But no matter how optimized, the Java program's speed is certainly inferior to the native code. Although Google's mash-up is not novel, it is a new attempt to put it into practice in an embedded environment. Design is always a choice, Google's choice is reasonable, but also need to practice testing.