Android系统外文翻译

《Android系统外文翻译》由会员分享，可在线阅读，更多相关《Android系统外文翻译（10页珍藏版）》请在毕设资料网上搜索。

1、附录 1： 外文原文 What Is Android? It can be said that, for a while, traditional desktop application developers have beenspoiled. This is not to say that traditional desktop application development is easier thanother forms of development. However, as traditional desktop application developers, wehave had

2、the ability to create almost any kind of application we can imagine. I amincluding myself in this grouping because I got my start in desktop programming. One aspect that has made desktop programming more accessible is that we havehad the ability to interact with the desktop operating system, and thu

3、s interact with anyunderlying hardware, pretty freely (or at least with minimal exceptions). This kind offreedom to program independently, however, has never really been available to thesmall group of programmers who dared to venture into the murky waters of cell phonedevelopment. For a long time, c

4、ell phone developers comprised a small sect of a slightly larger group of developers known as embedded device developers. Seen as a less “glamorous” sibling to desktopand later webdevelopment, embedded device development typically got the proverbial short end of the stick as far as hardware and oper

5、ating system features, because embedded device manufacturers were notoriously stingy on feature support. Embedded device manufacturers typically needed to guard their hardware secrets closely, so they gave embedded device developers few libraries to call when trying to interact with a specific devic

6、e. Embedded devices differ from desktops in that an embedded device is typically a “computer on a chip.” For example, consider your standard television remote control； it is not really seen as an overwhelming achievement of technological complexity. When any button is pressed, a chip interprets the

7、signal in a way that has been programmed into the device. This allows the device to know what to expect from the input device (key pad), and how to respond to those commands (for example, turn on the television). This is a simple form of embedded device programming. However, believe it or not, simpl

8、e devices such as these are definitely related to the roots of early cell phone devices and development. Most embedded devices ran (and in some cases still run) proprietary operating systems. The reason for choosing to create a proprietary operating system rather than use any consumer system was rea

9、lly a product of necessity. Simple devices did not need very robust and optimized operating systems. As a product of device evolution, many of the more complex embedded devices, such as early PDAs, household security systems, and GPSs, moved to somewhat standardized operating system platforms about

10、five years ago. Small-footprint operating systems such as Linux, or even an embedded version of Microsoft Windows, have become more prevalent on many embedded devices. Around this time in device evolution, cell phones branched from other embedded devices onto their own path. This branching is eviden

11、t when you examine their architecture. Nearly since their inception, cell phones have been fringe devices insofar as they run on proprietary softwaresoftware that is owned and controlled by the manufacturer, and is almost always considered to be a “closed” system. The practice of manufacturers using

12、 proprietary operating systems began more out of necessity than any other reason. That is, cell phone manufacturers typically used hardware that was completely developed in-house, or at least hardware that was specifically developed for the purposes of running cell phone equipment. As a result, ther

13、e were no openly available, off-the-shelf software packages or solutions that would reliably interact with their hardware. Since the manufacturers also wanted to guard very closely their hardware trade secrets, some of which could be revealed by allowing access to the software level of the device, t

14、he common practice was, and in most cases still is, to use completely proprietary and closed software to run their devices. The downside to this is that anyone who wanted to develop applications for cell phones needed to have intimate knowledge of the proprietary environment within which it was to r

15、un. The solution was to purchase expensive development tools directly from the manufacturer. This isolated many of the “homebrew” developers. Another, more compelling “necessity” that kept cell phone development out of the hands of the everyday developer was the hardware manufacturers solution to th

16、e “memory versus need” dilemma. Until recently, cell phones did little more than execute and receive phone calls, track your contacts, and possibly send and receive short text messages； not really the “Swiss army knives” of technology they are today. Even as late as 2002, cell phones with cameras we

17、re not commonly found in the hands of consumers. By 1997, small applications such as calculators and games (Tetris, for example) crept their way onto cell phones, but the overwhelming function was still that of a phone dialer itself. Cell phones had not yet become the multiuse, multifunction persona

18、l tools they are today. No one yet saw the need for Internet browsing, MP3 playing, or any of the multitudes of functions we are accustomed to using today. It is possible that the cell phone manufacturers of 1997 did not fully perceive the need consumers would have for an all-in-one device. However,

19、 even if the need was present, a lack of device memory and storage capacity was an even bigger obstacle to overcome. More people may have wanted their devices to be all-in-one tools, but manufacturers still had to climb the memory hurdle. To put the problem simply, it takes memory to store and run a

20、pplications on any device, cell phones included. Cell phones, as a device, until recently did not have the amount of memory available to them that would facilitate the inclusion of “extra” programs. Within the last two years, the price of memory has reached very low levels. Device manufacturers now

21、have the ability to include more memory at lower prices. Many cell phones now have more standard memory than the average PC had in the mid-1990s. So, now that we have the need, and the memory, we can all jump in and develop cool applications for cell phones around the world, right? Not exactly. Devi

22、ce manufacturers still closely guard the operating systems that run on their devices. While a few have opened up to the point where they will allow some Java-based applications to run within a small environment on the phone, many do not allow this. Even the systems that do allow some Java apps to ru

23、n do not allow the kind of access to the “core” system that standard desktop developers are accustomed to having. This barrier to application development began to crumble in November of 2007 whenGoogle, under the Open Handset Alliance, released Android. The Open Handset Allianceis a group of hardwar

24、e and software developers, including Google, NTT DoCoMo,Sprint Nextel, and HTC, whose goal is to create a more open cell phone environment. The first product to be released under the alliance is the mobile device operatingsystem, Android. (For more information about the Open Handset Alliance, see )W

25、ith the release of Android, Google made available a host of development toolsand tutorials to aid would-be developers onto the new system. Help files, the platformsoftware development kit (SDK), and even a developers community can be found atGoogles Android website, http:/ This site should be yourst

26、arting point, and I highly encourage you to visit the site. While cell phones running Linux, Windows, and even PalmOS are easy to find, as ofthis writing, no hardware platforms have been announced for Android to run on. HTC, LG Electronics, Motorola, and Samsung are members of the Open Handset Allia

27、nce, underwhich Android has been released, so we can only hope that they have plans for a fewAndroid-based devices in the near future. With its release in November 2007, the systemitself is still in a software-only beta. This is good news for developers because it gives usa rare advance look at a future system and a chance to begin developing applications thatwill run as soon as the hardware is released. Android, as a system, is a Java-based operating system that runs on the Linux 2.6 kernel.The system is very lightweight and full featured. Figure 1-1 shows the unmodifiedAndroid home screen.