XML基础教程(第2版)_第2章_规范的XML文件

mybati‎s第一天mybati‎s的基础知识‎课程安排：mybati‎s和spri‎n gmvc通‎过订单商品案例驱动第一天：基础知识（重点，内容量多）对原生态jd‎b c程序（单独使用jd‎b c开发）问题总结mybati‎s框架原理（掌握）mybati‎s入门程序用户的增、删、改、查mybati‎s开发dao‎两种方法：原始dao开‎发方法（程序需要编写‎d a o接口和‎d a o实现类‎）（掌握）mybait‎s的mapp‎e r接口（相当于dao‎接口）代理开发方法‎（掌握）mybati‎s配置文件S‎q lMapC‎onfig.xmlmybati‎s核心：mybati‎s输入映射（掌握）mybati‎s输出映射（掌握）mybati‎s的动态sq‎l（掌握）第二天：高级知识订单商品数据‎模型分析高级结果集映‎射（一对一、一对多、多对多）mybati‎s延迟加载mybati‎s查询缓存（一级缓存、二级缓存）mybait‎s和spri‎n g进行整合‎（掌握）mybati‎s逆向工程1对原生态jd‎bc程序中问‎题总结1.1环境java环境‎：jdk1.7.0_72eclips‎e：indigo‎mysql：5.11.2创建mysq‎l数据导入下边的脚‎本：sql_ta‎ble.sql：记录表结构sql_da‎t a.sql：记录测试数据‎，在实际企业开‎发中，最后提供一个‎初始化数据脚‎本1.3jdbc程序‎使用jdbc‎查询mysq‎l数据库中用‎户表的记录。

创建java‎工程，加入jar包‎：数据库驱动包‎（m ysql5‎.1）上边的是my‎sql驱动。

下边的是or‎a cle的驱‎动。

程序代码：1.4问题总结1、数据库连接，使用时就创建‎，不使用立即释‎放，对数据库进行‎频繁连接开启‎和关闭，造成数据库资‎源浪费，影响数据库性能。

设想：使用数据库连‎接池管理数据‎库连接。

2、将sql语句‎硬编码到ja‎v a代码中，如果sql 语句修改，需要重新编译‎java代码‎，不利于系统维‎护。

XPath 教程Next Page XPath 是一门在 XML 文档中查找信息的语言。

XPath 可用来在 XML 文档中对元素和属性进行遍 历。

XPath 是 W3C XSLT 标准的主要元素，并且 XQuery 和 XPointer 同时被构建于 XPath 表达 之上。

因此，对 XPath 的理解是很多高级 XML 应用的基础。

开始学习 XPath ！XPath 参考手册在 W3School，我们提供完整的 XPath 2.0、XQuery 1.0 和 XSLT 2.0 的内置函数参考手册。

XPath 函数内容目录XPath 简介 本章讲解 XPath 的概念。

XPath 节点 本章详细介绍 XPath 中不同类型的节点，以及节点之间的关系。

XPath 语法 本章讲解 XPath 的语法。

XPath 轴 本章讲解 XPath axes（轴）。

XPath 运算符 本章列出了可以用于 XPath 表达式的运算符。

XPath 实例 本章使用 "books.xml" 文档来演示一些 XPath 实例。

XPath 摘要 本文内容包括在本教程所学知识的一个总结，以及我们向你推荐的下一步应该学习的内容。

XPath 参考手册XPath 函数XPath 2.0、XQuery 1.0 和 XSLT 2.0 的内置函数。

XPath 简介 Previous Page Next Page XPath 是一门在 XML 文档中查找信息的语言。

XPath 用于在 XML 文档中通过元素和属性进行导 航。

在学习之前应该具备的知识：在您继续学习之前，应该对下面的知识有基本的了解： HTML / XHTML  XML / XML 命名空间如果您希望首先学习这些项目，请在我们的 首页 访问这些教程。

什么是 XPath? XPath 使用路径表达式在 XML 文档中进行导航  XPath 包含一个标准函数库  XPath 是 XSLT 中的主要元素  XPath 是一个 W3C 标准XPath 路径表达式XPath 使用路径表达式来选取 XML 文档中的节点或者节点集。

About the T utorialXML stands for Ex tensible M arkup L anguage and is a text-based markup language derived from Standard Generalized Markup Language (SGML).This tutorial will teach you the basics of XML. The tutorial is divided into sections such as XML Basics, Advanced XML, and XML tools. Each of these sections contain related topics with simple and useful examples.AudienceThis reference has been prepared for beginners to help them understand the basic to advanced concepts related to XML. This tutorial will give you enough understanding on XML from where you can take yourself to a higher level of expertise. PrerequisitesBefore proceeding with this tutorial, you should have basic knowledge of HTML and JavaScript.Copyright & DisclaimerCopyright 2018 by Tutorials Point (I) Pvt. Ltd.All the content and graphics published in this e-book are the property of Tutorials Point (I) Pvt. Ltd. The user of this e-book is prohibited to reuse, retain, copy, distribute or republish any contents or a part of contents of this e-book in any manner without written consent of the publisher.We strive to update the contents of our website and tutorials as timely and as precisely as possible, however, the contents may contain inaccuracies or errors. Tutorials Point (I) Pvt. Ltd. provides no guarantee regarding the accuracy, timeliness or completeness of our website or its contents including this tutorial. If you discover any errors on our website or inthistutorial,******************************************T able of ContentsAbout the Tutorial (i)Audience (i)Prerequisites (i)Copyright & Disclaimer (i)Table of Contents (ii)XML BASICS (1)1.XML – Overview (2)XML Usage (2)What is Markup? (3)Is XML a Programming Language? (3)2.XML – Syntax (4)3.XML – Documents (9)Document Prolog Section (9)Document Elements Section (10)4.XML – Declaration (11)5.XML – Tags (14)Start Tag (14)End Tag (14)Empty Tag (14)XML Tags Rules (15)6.XML – Elements (16)Empty Element (16)XML Elements Rules (17)7.XML – Attributes (18)Attribute Types (19)Element Attribute Rules (20)8.XML – Comments (21)XML Comments Rules (21)9.XML – Character Entities (22)Types of Character Entities (22)10.XML – CDATA Sections (24)CDATA Rules (25)11.XML – Whitespaces (26)Significant Whitespace (26)Insignificant Whitespace (26)12.XML – Processing (27)Processing Instructions Rules (28)13.XML – Encoding (29)Encoding Types (29)14.XML – Validation (31)Well-formed XML Document (31)Valid XML Document (32)ADVANCE XML (33)15.XML – DTDs (34)Internal DTD (34)External DTD (36)Types (37)16.XML – Schemas (39)Definition Types (40)17.XML – Tree Structure (42)18.XML – DOM (45)19.XML – Namespaces (47)Namespace Declaration (47)20.XML – Databases (48)XML Database Types (48)XML- Enabled Database (48)XML TOOLS (50)21.XML – Viewers (51)Text Editors (51)Firefox Browser (52)Chrome Browser (52)Errors in XML Document (52)22.XML – Editors (54)Open Source XML Editors (54)23.XML – Parsers (55)24.XML – Processors (56)Types (56)XML Basics11.XML stands for E xtensible M arkup L anguage. It is a text-based markup language derived from Standard Generalized Markup Language (SGML).XML tags identify the data and are used to store and organize the data, rather than specifying how to display it like HTML tags, which are used to display the data. XML is not going to replace HTML in the near future, but it introduces new possibilities by adopting many successful features of HTML.There are three important characteristics of XML that make it useful in a variety of systems and solutions:∙XML is extensible: XML allows you to create your own self-descriptive tags or language, that suits your application.∙XML carries the data, does not present it: XML allows you to store the data irrespective of how it will be presented.∙XML is a public standard: XML was developed by an organization called the World Wide Web Consortium (W3C) and is available as an open standard.XML UsageA short list of XML usage says it all:∙XML can work behind the scene to simplify the creation of HTML documents for large web sites.∙XML can be used to exchange the information between organizations and systems.∙XML can be used for offloading and reloading of databases.∙XML can be used to store and arrange the data, which can customize your data handling needs.∙XML can easily be merged with style sheets to create almost any desired output.∙Virtually, any type of data can be expressed as an XML document.2What is Markup?XML is a markup language that defines set of rules for encoding documents in a format that is both human-readable and machine-readable. So, what exactly is a markup language? Markup is information added to a document that enhances its meaning in certain ways, in that it identifies the parts and how they relate to each other. More specifically, a markup language is a set of symbols that can be placed in the text of a document to demarcate and label the parts of that document.Following example shows how XML markup looks, when embedded in a piece of text:This snippet includes the markup symbols, or the tags such as <message>...</message> and <text>... </text>. The tags <message> and </message> mark the start and the end of the XML code fragment. The tags <text> and </text> surround the text Hello, world!. Is XML a Programming Language?A programming language consists of grammar rules and its own vocabulary which is used to create computer programs. These programs instruct the computer to perform specific tasks. XML does not qualify to be a programming language as it does not perform any computation or algorithms. It is usually stored in a simple text file and is processed by special software that is capable of interpreting XML.32.In this chapter, we will discuss the simple syntax rules to write an XML document. Following is a complete XML document:You can notice, there are two kinds of information in the above example: ∙Markup, like <contact-info>∙The text, or the character data, Tutorials Point and (040) 123-4567The following diagram depicts the syntax rules to write different types of markup and text in an XML document.Let us see each component of the above diagram in detail.4XML DeclarationThe XML document can optionally have an XML declaration. It is written as follows:Where version is the XML version and encoding specifies the character encoding used in the document.Syntax Rules for XML Declaration∙The XML declaration is case sensitive and must begin with "<?xml>" where "xml"is written in lower-case.∙If the document contains XML declaration, then it strictly needs to be the first statement of the XML document.∙The XML declaration strictly needs be the first statement in the XML document.∙An HTTP protocol can override the value of encoding that you put in the XML declaration.T ags and ElementsAn XML file is structured by several XML-elements, also called XML-nodes or XML-tags. The names of XML-elements are enclosed in triangular brackets < > as shown below:Syntax Rules for Tags and ElementsElement Syntax: Each XML-element needs to be closed either with start or with end elements as shown below:or in simple-cases, just this way:Nesting of Elements: An XML-element can contain multiple XML-elements as its children, but the children elements must not overlap. i.e., an end tag of an element must have the same name as that of the most recent unmatched start tag.56The following example shows incorrect nested tags:The following example shows correct nested tags:Root Element: An XML document can have only one root element. For example, following is not a correct XML document, because both the x andy elements occur at the top level without a root element:The following example shows a correctly formed XML document:Case Sensitivity: The names of XML-elements are case-sensitive. That means the name of the start and the end elements need to be exactly in the same case.For example, <contact-info> is different from <Contact-Info>.XML AttributesAn attribute specifies a single property for the element, using a name/value pair. An XML-element can have one or more attributes. For example:Here href is the attribute name and / is attribute value.Syntax Rules for XML Attributes∙Attribute names in XML (unlike HTML) are case sensitive. That is,HREF and href are considered two different XML attributes.∙Same attribute cannot have two values in a syntax. The following example shows incorrect syntax because the attribute b is specified twice:∙Attribute names are defined without quotation marks, whereas attribute values must always appear in quotation marks. Following example demonstrates incorrect xml syntax:In the above syntax, the attribute value is not defined in quotation marks.XML ReferencesReferences usually allow you to add or include additional text or markup in an XML document. References always begin with the symbol "&" which is a reserved character and end with the symbol ";". XML has two types of references:∙Entity References: An entity reference contains a name between the start and the end delimiters. For example, &amp; where amp is name. The name refers toa predefined string of text and/or markup.∙Character References: These contain references, such as &#65;, contains a hash mark (“#”) followed by a number. The number always refers to the Unicode code of a character. In this case, 65 refers to alphabet "A".XML T extThe names of XML-elements and XML-attributes are case-sensitive, which means the name of start and end elements need to be written in the same case. To avoid character encoding problems, all XML files should be saved as Unicode UTF-8 or UTF-16 files.Whitespace characters like blanks, tabs and line-breaks between XML-elements and between the XML-attributes will be ignored.Some characters are reserved by the XML syntax itself. Hence, they cannot be used directly. To use them, some replacement-entities are used, which are listed below:783.An XML document is a basic unit of XML information composed of elements and other markup in an orderly package. An XML document can contain a wide variety of data. For example, database of numbers, numbers representing molecular structure or a mathematical equation.XML Document ExampleA simple document is shown in the following example:The following image depicts the parts of XML document.Document Prolog SectionDocument Prolog comes at the top of the document, before the root element. This section contains:∙XML declaration∙Document type declarationYou can learn more about XML declaration in this chapter : XML Declaration.Document Elements SectionDocument Elements are the building blocks of XML. These divide the document into a hierarchy of sections, each serving a specific purpose. You can separate a document into multiple sections so that they can be rendered differently, or used by a search engine. The elements can be containers, with a combination of text and other elements.9You can learn more about XML elements in this chapter : XML Elements104.This chapter covers XML declaration in detail. XML declaration contains details that prepare an XML processor to parse the XML document. It is optional, but when used, it must appear in the first line of the XML document.SyntaxFollowing syntax shows XML declaration:Each parameter consists of a parameter name, an equals sign (=), and parameter value inside a quote. Following table shows the above syntax in detail:11RulesAn XML declaration should abide with the following rules:∙If the XML declaration is present in the XML, it must be placed as the first line in the XML document.∙If the XML declaration is included, it must contain version number attribute.∙The parameter names and values are case-sensitive.∙The names are always in lower case.∙The order of placing the parameters is important. The correct order is:version, encoding and standalone.∙Either single or double quotes may be used.∙The XML declaration has no closing tag, i.e. </?xml>XML Declaration ExamplesFollowing are few examples of XML declarations:XML declaration with no parameters:XML declaration with version definition:XML declaration with all parameters defined:XML declaration with all parameters defined in single quotes:125.Let us learn about one of the most important part of XML, the XML tags. XML tags form the foundation of XML. They define the scope of an element in XML. They can also be used to insert comments, declare settings required for parsing the environment, and to insert special instructions.We can broadly categorize XML tags as follows:Start T agThe beginning of every non-empty XML element is marked by a start-tag. Following is an example of start-tag:End T agEvery element that has a start tag should end with an end-tag. Following is an example of end-tag:Note, that the end tags include a solidus ("/") before the name of an element.Empty T agThe text that appears between start-tag and end-tag is called content. An element which has no content is termed as empty. An empty element can be represented in two ways as follows:A start-tag immediately followed by an end-tag as shown below:A complete empty-element tag is as shown below:Empty-element tags may be used for any element which has no content.13End of ebook previewIf you liked what you saw…Buy it from our store @ https://14。

[Mixly私人定制][非官方、零基础、不完全、简明入门手册][Blue]2016年1月22日前言：以下教程以Mixly0.96版本为例说明，你需要的基本技能是会写Arduino库文件。

Mixly里面我们需要修改的代码语言大部分为JavaScript，本人尝试修改Mixly以前也没接触过这门语言，全靠对里面现成例子的模仿和复制粘贴。

感谢：由衷感谢傅骞老师和其带领的团队对国内创客教育的无私奉献，让我们这种缺少软件开发大牛的小团队也能用上高大上的图形化编程软件。

一、总体框架步骤说明Mixly的基本原理是把图形化的模块直接翻译为C语言，这个翻译机制现在还不是很智能，做的事情只是把模块预先对应的C语言原原本本的替换而已，所以先搞明白这点，你已经离成功不远了。

接着说下需要改动的几个地方，后面会用实际事例一一说明：1.Mixly0.96\company增加xxx.XML文件，文件里定义了模块名称、种类、相关文件的路径2.Mixly0.96\arduino-1.7.8\libraries添加自己的arduino 库，这个不多说了，不懂Google。

3.Mixly0.96\blockly\blocks\company添加xxx.js文件，文件定义了你定制的图形化模块的样子。

4.Mixly0.96\blockly\generators\arduino\company添加翻译到arduino语言的xxx.js5.Mixly0.96\blockly\media添加模块图片，也可以不需要，看你了。

6.Mixly0.96\blockly\msg\js添加翻译字符功能的xxx.js文件，主要修改中文，繁体，英文，西班牙几种。

二、开干下面我们以一个LED模块为例，带你快速的走一遍。

这里需要说明一点，你可能觉得一个LED，不是直接就可以用Mixly的输入输出里面的模块就可以了吗，为什么还要搞自己的模块。

这里我说下我的几点看法：1.以我们Nova模块为例，我们Nova模块的主控板兼容Arduino UNO，但是在管脚布局上做了优化和更改，定义了自己的端口属性。

第1章绪论1.1 XML与模式1.1.1 XML简介1. XML声明2. 元素3. 属性4. 处理指令5. 注释6. 命名空间图1-1一个XML文档实例1.1.2 DTD简介2电子商务基础教程(第二版)图1-1一个XML文档实例图1-2一个XML DTD实例网络工程技术与实验教程 3 1.1.3 XML模式简介图1-3一个XML Schema实例4电子商务基础教程(第二版)1. 元素和属性2. 数据类型3. 匿名与命名4. 全局与局部5. 实例与模式1.2 XPath查询语言1.2.1 XPath简介1.2.2数据模型1. 文档结点2. 元素结点3. 属性结点4. 命名空间结点5. 处理指令结点6. 注释结点7. 文本结点图1-4一个查询数据模型实例网络工程技术与实验教程 5 1.2.3定位路径与定位步1. XPath轴2. 结点测试3. 谓词4. 定位路径表达式的缩写形式1.2.4基本表达式1.2.5函数调用1. 结点集合函数2. 字符串函数3. 布尔函数4. 数字函数1.3 XQuery查询语言1.3.1 XQuery简介1.3.2 XQuery查询的处理模型6电子商务基础教程(第二版)图1-5 XQuery查询的处理模型网络工程技术与实验教程71. 数据模型的产生2. 数据模型的序列化3. 模式导入4. 静态分析5. 动态计算阶段1.3.3 XQuery语法与查询实例1. FLWOR表达式2. 条件表达式3. 序列表达式4. 比较表达式5. 构造器6. 定量表达式1.4 XML查询代数参考文献1. World Wide Web Consortium. Extensible Markup Language (XML) 1.0 (Third Edition). W3C Recommendation. 4 February 2004. http: ///TR/REC-xml/2. Bosak J, Bray T, Connolly D, et al. W3C XML Specification ("XMLspec") DTD Version2.1. 15 February 2000. http: //www.w/XML/1998/06/xmlspec-report-v21.htm3. World Wide Web Consortium. XML Schema Part 0: Primer. W3C Recommendation, 2 May 2001. http: ///TR/xmlschema-0/4. World Wide Web Consortium. XML Schema Part 1: Structures. W3C Recommendation, 2 May 2001. http: ///TR/xmlschema-1/5. World Wide Web Consortium. XML Schema Part 2: Datatypes. W3C Recommendation, 2 May 2001. http: ///TR/xmlschema-2/6. World Wide Web Consortium. XML Schema: Formal Description. W3C Working Draft, 25 September 2001. http: ///TR/xmlschema-formal/7. 万常选. DTD与Schema在电子商务应用中的比较研究. 计算机应用研究, 2002,8电子商务基础教程(第二版)19(9): 30～328. World Wide Web Consortium. XML Path Language (XPath) Version 1.0. W3C Recom-mendation. 16 November 1999. http: ///TR/xpath9. World Wide Web Consortium. XML Path Language (XPath) 2.0. W3C Working Draft. 23 July 2004. http: ///TR/xpath2010. World Wide Web Consortium. XQuery 1.0: An XML Query Language. W3C Working Draft. 23 July 2004. http: ///TR/xquery/11. World Wide Web Consortium. XML Query Requirements. W3C Working Draft, 12 No-vember 2003. http: ///TR/xquery-requirements/12. World Wide Web Consortium. XQuery 1.0 and XPath 2.0 Data Model. W3C Working Draft. 23 July 2004. http: ///TR/xpath-datamodel/13. World Wide Web Consortium. XQuery 1.0 and XPath 2.0 Functions and Operators. W3C Working Draft. 23 July 2004. http: ///TR/xpath-functions14. World Wide Web Consortium. XQuery 1.0 and XPath 2.0 Formal Semantics. W3C Working Draft, 20 February 2004. http: ///TR/xquery-semantics/15. World Wide Web Consortium. XML Query Use Cases. W3C Working Draft. 12 Novem-ber 2003. http: ///TR/xquery-use-cases16. World Wide Web Consortium. XSLT 2.0 and XQuery 1.0 Serialization, W3C Working Draft. 23 July 2004. http: ///TR/xslt-xquery-serialization17. World Wide Web Consortium. Extensible Stylesheet Language (XSL). W3C Recom-mendation, 15 October 2001. http: ///TR/xsl/18. World Wide Web Consortium. XSL Transformations (XSLT) Version 1.0. W3C Recom-mendation, 16 November 1999. http: ///TR/xslt/19. World Wide Web Consortium. XML Pointer Language (XPointer) Version 1.0. W3C Working Draft, 16 August 2002. http: ///TR/xpointer/20. Robie J, Lapp J, and Schach D. XML Query Language(XQL). In: Marchiori M et al Eds. Proceedings of the International Conference on Query Languages (QL'98). Boston, Massachu-setts, USA. December 3-4, 1998. http: ///TandS/QL/QL98/pp/xql.html21. Deutsch A, Fernandez M, Florescu D, et al. XML QL: A Query Language for XML. 1998. http: ///TR/NOTE-xml-ql/22. Chamberlin D, Robie J, and Florescu D. Quilt: An XML Query Language for Heteroge-neous Data Sources. In: Suciu D et al Eds. Proceedings of the 3th WebDB International Workshop on the Web and Databases (Lecture Notes in Computer Science, V ol. 1997). Dallas, Texas, USA. May 18-19, 2000. Berlin: Springer, 2001. 1～2523. Bonifati A and Ceri S. Comparative Analysis of Five XML Query Languages. ACM SIGMOD Record, 2000, 29(1): 68～7924. Mchugh J, Abiteboul S, Goldman R, et al. Lore: A Database Management System for Semistructured Data. ACM SIGMOD Record, 1997, 26(3): 54～6625. McHugh J, and Widom J. Query Optimization for XML. In: Atkinson M P et al Eds.网络工程技术与实验教程9Proceedings of the 25th VLDB International Conference on Very Large Database. Edinburgh, Scotland. September 7 10, 1999. San Francisco: Morgan Kaufmann Publishers, 1999. 315～32626. Beech D, Malhotra A, and Rys M. A Formal Data Model and Algebra for XML. Commu-nication to the W3C, September 1999. 1～26. http: ///dbseminar/Archive/FallY99/malhotra tsld001.htm27. Beeri C and Tzaban Y. SAL: An Algebra for Semistructured Data and XML. In: Cluet S et al Eds. Proceedings of the WebDB International Workshop on the Web and Databases. Phila-delphia, USA. June 3 4, 1999. 46～5128. Christophides V, Cluet S, Simeon J. On Wrapping Query Languages and Efficient XML Integration. In: Chen W et al Eds. Proceedings of the 19th ACM SIGMOD International Confe-rence on Management of Data. Dallas, Texas, USA. May 14-19, 2000. New York: ACM Press, 2000. 141～15229. Fernandez M, Simeon J, Wadler P. An Algebra for XML Query. In: Kapooe S et al Eds. Proceedings of the 20th FSTTCS International Conference on Foundations of Software Technol-ogy and Theoretical Computer Science (Lecture Notes in Computer Science, V ol. 1974). New Delhi, India. December 13-15, 2000. Springer Verlap, 2000. 11～4530. Fernandez M, Simeon J, Wadler P. A Semi monad for Semi structured Data. In: Bussche J V et al Eds. Proceedings of the 8th ICDT International Conference on Database Theory (Lecture Notes in Computer Science, V ol. 1973). London, UK. January 4-6, 2001. Heidelberg: Springer Verlag, 2001. 263～30031. Galanis L, Viglas E, DeWitt D J, et al. Following the Paths of XML Data: An Algebraic framework for XML Query Evaluation. Niagara Publications. http: ///niagara/. 2001. 1～2532. Jagadish H V, Lakshmanan L V S, Srivastava D, et al. TAX: A Tree Algebra for XML. In: Clark J et al Eds. Proceedings of the International Workshop on Database Programming Lan-guages (Lecture Notes in Computer Science, V ol. 2397). Rome, Italy. September 8-10, 2001. Heidelberg: Springer Verlag, 2002. 149～164。

Android移动开发基础教程第2章Android界面开发Android界面开发是Android移动开发的基础知识之一，它涉及到Android应用程序的用户界面设计和实现。

在本章中，我们将学习如何使用XML布局文件和Java代码来创建和定制Android应用程序的用户界面。

Android应用程序的用户界面主要由Activity和Layout组成。

Activity是应用程序的一个界面，它负责处理用户输入和显示结果。

Layout是用来定义和描述界面上的元素和布局的XML文件。

在Android界面开发中，我们可以使用多种布局类型来实现不同的界面效果。

常见的布局类型包括线性布局、相对布局和帧布局等。

我们可以通过在XML文件中定义布局类型和属性来创建界面布局，并使用Java代码来实现布局的动态调整和交互。

在创建界面布局时，我们可以使用各种视图组件来实现不同的功能和交互效果。

常见的视图组件包括文本框、按钮、图像视图、列表视图和网格视图等。

我们可以在XML布局文件中使用这些视图组件，并使用Java代码来处理它们的事件和动作。

除了布局和视图组件外，Android界面开发还包括一些其他的功能，如主题和样式的定制、动画效果的实现和数据的绑定等。

我们可以通过在XML文件中定义主题和样式来改变应用程序的外观和风格。

我们还可以使用Android提供的动画API来实现界面元素的动态效果。

数据绑定是将数据模型和界面元素绑定在一起，使得数据的变化能够自动更新到界面上。

在Android界面开发中，我们需要考虑不同屏幕尺寸和分辨率的适配问题。

Android提供了多种方式来适配不同屏幕的布局和显示效果，如使用百分比布局和使用不同的资源文件等。

总结起来，Android界面开发是Android移动开发的基础知识之一，它涉及到Android应用程序的用户界面设计和实现。

在本章中，我们学习了如何使用XML布局文件和Java代码来创建和定制Android应用程序的用户界面，包括布局类型、视图组件、主题和样式、动画效果和数据绑定等。

C++的XML编程经验――LIBXML2库使用指南写这篇文章的原因有如下几点：1)C++标准库中没有操作XML的方法，用C++操作XML文件必须熟悉一种函数库，LIBXML2是其中一种很优秀的XML库，而且它同时支持多种编程语言；2)LIBXML2库的Tutorial写得不太好，尤其是编码转换的部分，不适用于中文编码的转换；3)网上的大多数关于Libxml2的介绍仅仅是翻译了自带的资料，没有详细介绍如何在windows平台下进行编程，更很少提到如何解决中文问题。

基于以上几点原因，决定写一个在Windows平台下，使用C/C++语言，应用LibXml2库来进行xml文档操作，同时使用ICONV库进行中文编码转换的文档。

其中还涉及了Makefile、XPATH等相关内容。

本文中所有的源代码在/Files/wxb_nudt/xml_src.rar。

1.下载与安装LIBXML2和ICONVLibxml2是一个C语言的XML程序库，可以简单方便的提供对XML文档的各种操作，并且支持XPATH查询，以及部分的支持XSLT转换等功能。

Libxml2的下载地址是/，完全版的库是开源的，并且带有例子程序和说明文档。

最好将这个库先下载下来，因为这样可以查看其中的文档和例子。

windows版本的的下载地址是/libxml.en.html；这个版本只提供了头文件、库文件和dll，不包含源代码、例子程序和文档。

在文本中，只需要下载libxml2库、iconv库和zlib库就行了（注意，libxml2库依赖iconv和zlib库，本文中重点关注libxml2和iconv，zlib不介绍），我使用的版本是libxml2-2.6.30.win32.zip、zlib-1.2.3.win32.zip 和iconv-1.9.2.win32.zip。

在编程的时候，我们使用windows版本的libxml2、zlib和iconv，将其解压缩到指定文件夹，例如D:"libxml2-2.6.30.win32，D:"zlib-1.2.3.win32以及D:"iconv-1.9.2.win32。

最主要的不同：∙XHTML 元素必须被正确地嵌套。

∙XHTML 元素必须被关闭。

∙标签名必须用小写字母。

∙XHTML 文档必须拥有根元素。

元素必须被正确地嵌套在 HTML 中，某些元素可以像这样彼此不正确地嵌套：<b><i>This text is bold and italic</b></i>在 XHTML 中，所有的元素必须像这样彼此正确地嵌套：<b><i>This text is bold and italic</i></b>提示：在嵌套列表中一个容易犯的错误，是忘记内部列表必须位于 li 元素中，就像下面这样：这是错误的：<ul><li>Coffee</li><li>Tea<ul><li>Black tea</li><li>Green tea</li></ul><li>Milk</li></ul>这是正确的：<ul><li>Coffee</li><li>Tea<ul><li>Black tea</li><li>Green tea</li></ul></li><li>Milk</li></ul>注意：在正确代码的例子中，我们在 </ul> 之后插入了一个 </li> 标签。

XHTML 元素必须被关闭非空标签必须使用结束标签。

这是错误的：<p>This is a paragraph<p>This is another paragraph这是正确的：<p>This is a paragraph</p><p>This is another paragraph</p>空标签也必须被关闭空标签也必须使用结束标签，或者其开始标签必须使用/>结尾。