Abstract: The combination of smart phones and Internet services is the future trend of information development and software applications. Is the Android mobile operating system based on Linux announced by Google in November 2007? The open source mobile phone operating system with V2.6 kernel has wide application and development prospects. In this paper, the three-tier architecture transplantation in Web development is improved to a three-tier system architecture of data server, application server and mobile client. A software development framework based on web services is proposed, and Android city guides are developed based on this framework. The system can realize online query of basic information such as city's main attractions, accommodation, food, shopping and so on.
1 Introduction
The mobile phone is a convenient communication tool that people can carry around. With the advent of smart phones, it has also become an important way for people to obtain information quickly and conveniently. And more and more mobile phone software is rapidly changing people's lives. However, due to the limitation of hardware and storage space, the information stored in the mobile phone is also restricted.
In this article, the combination of mobile phone software development and the Internet, transplanting the Web three-tier architecture to the development of mobile phone software, design and implementation of mobile phone application software based on the Android operating system-the city tour guide system The classified query of hotels and inns and the information query of surrounding scenic spots, hotels and inns through the user's mobile phone positioning function have fulfilled the query needs of city tour guides for play, food and accommodation.
2 Introduction to the Android operating system
Is Android based on Linux announced by Google in November 2007? Open source mobile phone operating system with V2.6 kernel. Initially, Android was deployed in the mobile phone field, including smart phones and cheaper flip phones. However, Android's comprehensive computing services and rich feature support are fully capable of expanding beyond the mobile phone market. Therefore, Android can also be used for other platforms and applications, the development prospect is very broad.
The Android system uses a layered architecture, from the upper layer to the lower layer are the application layer, the application framework layer, the system runtime library and the Linux core layer. In the application layer, it provides rich core applications, including email client, SMS short message program, calendar, map, browser, contact management program, etc. All applications are written in JAVA language. The application framework layer simplifies the reuse of components, any application can publish or use function blocks released by other applications. The system runtime contains a set of core libraries and Dalvik virtual machine. Application framework layer. The Linux core layer is used to provide the underlying services of the system. It is located between the hardware and other software layers, and uses the YAFFS2 file system.
3 System framework design
In Web-based software development, the Web three-tier architecture is commonly used, namely the user interface layer, business logic layer, and data access layer. The user interface layer, that is, the client or browser, is mainly responsible for the display of data. The business logic layer, that is, the application server, is mainly responsible for the business logic processing of data. The data access layer, that is, the data server, is mainly responsible for accessing the database.
The Web three-tier architecture can be transplanted into the development of mobile phone applications. The mobile phone application is used as a client and is responsible for the work of the user interface layer. A large amount of data is stored in the Internet data server. Therefore, the combination of the smart phone and the Internet can make the mobile phone easily and conveniently access a large amount of data on the Internet.
In the Android-based city tour guide system, a three-tier architecture of client, application server and data server is adopted. The overall architecture of this system is shown in Figure 1. The client is a mobile application based on the Android operating system, and is responsible for data input, analysis, and display. The application server mainly provides services in the form of Web Services, and uses Lucene index and Chinese word cutting technology in data processing. The data server is mainly responsible for data storage, and the database uses MySQL.
The overall architecture of the system is divided into three parts, each part is relatively independent, and the storage, processing and display of data are separated, which is conducive to the development and maintenance of the system; the connections between the various parts are connected by software, which is also conducive to the change of the system And upgrade.
Figure 1 System architecture diagram
4 System block diagram
The city tour guide system mainly realizes the query of information such as city scenic spots, shopping, accommodation, etc., and the related information of the surroundings through mobile phone positioning. The block diagram of the system is shown in Figure 2. Among them, in each module of scenic spots, shopping, and accommodation, further detailed queries can be made according to the city's zone query, precise query, and ranking.
Figure 2 System module diagram
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