Android applications are developed using Java and can be ported rather easily to thenew platform。 If you have not yet downloaded Java or are unsure about which version youneed, I detail the installation of the development environment in Chapter 2。 Other features of Android include an accelerated 3-D graphics engine (based on hardware support),database support powered by SQLite, and an integrated web browser。
If you are familiar with Java programming or are an OOP developer of any sort, youare likely used to programmatic user interface (UI) development—that is, UI placementwhich is handled directly within the program code。 Android, while recognizing and allowingfor programmatic UI development, also supports the newer, XML-based UI layout。 XMLUI layout is a fairly new concept to the average desktop developer。 I will cover boththe XML UI layout and the programmatic UI development in the supporting chaptersof this book。
One of the more exciting and compelling features of Android is that, because of itsarchitecture, third-party applications—including those that are “home grown”—areexecuted with the same system priority as those that are bundled with the core system。This is a major departure from most systems, which give embedded system apps agreater execution priority than the thread priority available to apps created by third-partydevelopers。 Also, each application is executed within its own thread using a very lightweight virtual machine。
Aside from the very generous SDK and the well-formed libraries that are available tous to develop with, the most exciting feature for Android developers is that we now haveaccess to anything the operating system has access to。 In other words, if you want tocreate an application that dials the phone, you have access to the phone’s dialer; if youwant to create an application that utilizes the phone’s internal GPS (if equipped), you haveaccess to it。 The potential for developers to create dynamic and intriguing applications is now wide open。
Android applications are developed in Java。 Android itself is not a language, but ratheran environment within which to run applications。 As such, you can theoretically useany distribution or integrated development environment (IDE) you have at your disposalto begin your development。 In fact, you can choose to use no IDE at all。
If you are more comfortable with one Java IDE over any other, such as JBuilderby Borland or the open source NetBeans, feel free to use it。 With a moderate level of experience, you should still be able to follow along with the majority of the examples in this book。 However, the Open Handset Alliance and Google do endorse one JavaIDE over any others: Eclipse。
Eclipse is also available for Mac and Linux。 Having greater availability, on numerousoperating systems, means that almost anyone can develop Android applications onany computer。 However, the examples and screenshots in this book are given fromthe Microsoft Windows version of Eclipse。 Keep this in mind if you are using Eclipsein a non-Microsoft environment; your interface may look slightly different from thescreenshots, but the overall functionality should not change。 If there is a major changein operation of Eclipse under Linux, I will include an example of that change。 I willprovide several examples from within a Linux environment。 The majority of these examples will be from the Linux/Android command-line environment。
Navigate to the Eclipse Downloads page at www。eclipse。org/downloads, shown in the following illustration。 As the opening paragraph states, the JRE is required (Java 5 JRE recommended) to develop in Eclipse, which you took care of in the previous section。 Download the Eclipse IDE for Java Developers from this site。 The package is relativelysmall (79MB) and should download fairly quickly。 Be sure not to download the EclipseIDE for Java EE Developers, as this is a slightly different product and I will not be Android应用程序英文文献和中文翻译(2):http://www.youerw.com/fanyi/lunwen_28979.html