Android开发8――利用pull解析器读写XML文件

一、基本介绍

对XML解析有SAX和DOM等多种方式，Android中极力推荐xmlpull方式解析xml。xmlpull不仅可用在Android上同样也适用于javase，但在javase环境中需自己获取xmlpull所依赖的类库，kxml2-2.3.0.jar，xmlpull_1_1_3_4c.jar。

jar包下载网址
http://www.xmlpull.org/
http://kxml.sourceforge.net/

二、例子

读取到xml的声明返回数字0 START_DOCUMENT;
读取到xml的结束返回数字1 END_DOCUMENT ;
读取到xml的开始标签返回数字2 START_TAG
读取到xml的结束标签返回数字3 END_TAG
读取到xml的文本返回数字4 TEXT

                    <?xmlversion="1.0"encoding="UTF-8"?>
            <people>
            <personid="001">
            <name>XY1</name>
            <age>22</age>
            </person>
            <personid="002">
            <name>XY2</name>
            <age>22</age>
            </person>
            </people>

                    packagecn.xy.service; 
            
            importjava.io.InputStream; 
            importjava.io.OutputStream; 
            importjava.util.ArrayList; 
            importjava.util.List; 
            
            importorg.xmlpull.v1.XmlPullParser; 
            importorg.xmlpull.v1.XmlSerializer; 
            
            importandroid.util.Xml; 
            importcn.xy.model.Person; 
            
            
            publicclassPersonService 
            { 
             
            publicListgetPeople(InputStreamxml)throwsException 
            { 
            Listlst=null; 
            Personperson=null; 
            
            //利用ANDROID提供的API快速获得pull解析器 
            XmlPullParserpullParser=Xml.newPullParser(); 
            
            //设置需要解析的XML数据 
            pullParser.setInput(xml,"UTF-8"); 
            
            //取得事件 
            intevent=pullParser.getEventType(); 
            
            //若为解析到末尾 
            while(event!=XmlPullParser.END_DOCUMENT)//文档结束 
            { 
            StringnodeName=pullParser.getName(); 
            switch(event) 
            { 
            caseXmlPullParser.START_DOCUMENT://文档开始 
            lst=newArrayList(); 
            break; 
            caseXmlPullParser.START_TAG://标签开始 
            if("person".equals(nodeName)) 
            { 
            Stringid=pullParser.getAttributeValue(0); 
            person=newPerson(); 
            person.setId(id); 
            } 
            if("name".equals(nodeName)) 
            { 
            Stringname=pullParser.nextText(); 
            person.setName(name); 
            } 
            if("age".equals(nodeName)) 
            { 
            intage=Integer.valueOf(pullParser.nextText()); 
            person.setAge(age); 
            } 
            break; 
            caseXmlPullParser.END_TAG://标签结束 
            if("person".equals(nodeName)) 
            { 
            lst.add(person); 
            person=null; 
            } 
            break; 
            } 
            event=pullParser.next();//下一个标签 
            } 
            returnlst; 
            } 
            
             
            publicvoidsaveDataToXML(OutputStreamos,Listlst)throwsException 
            { 
            XmlSerializerxs=Xml.newSerializer(); 
            xs.setOutput(os,"UTF-8"); 
            xs.startDocument("UTF-8",true); 
            xs.startTag(null,"people"); 
            for(Personp:lst) 
            { 
            xs.startTag(null,"person"); 
            xs.attribute(null,"person",p.getId()); 
            
            xs.startTag(null,"name"); 
            xs.text(p.getName()); 
            xs.endTag(null,"name"); 
            
            xs.startTag(null,"age"); 
            xs.text(p.getAge().toString()); 
            xs.endTag(null,"age"); 
            
            xs.endTag(null,"person"); 
            } 
            xs.endTag(null,"people"); 
            xs.endDocument(); 
            os.flush(); 
            os.close(); 
            } 
            } 
            
             
            
            publicclassTestClassextendsAndroidTestCase 
            { 
            publicvoidtestPeople()throwsException 
            { 
            PersonServiceps=newPersonService(); 
            InputStreamxml=this.getClass().getClassLoader().getResourceAsStream("person.xml"); 
            Listlst=ps.getPeople(xml); 
            Assert.assertEquals("XY1",lst.get(0).getName()); 
            } 
            
            publicvoidtestSave()throwsException 
            { 
            PersonServiceps=newPersonService(); 
            Listlst=newArrayList(); 
            lst.add(newPerson("0001","XY0001",20)); 
            lst.add(newPerson("0002","XY0002",20)); 
            FilexmlFile=newFile(this.getContext().getFilesDir(),"xy.xml");//data/data/packagename/files 
            OutputStreamos=newFileOutputStream(xmlFile); 
            ps.saveDataToXML(os,lst); 
            } 
            }

本文参考自金旭亮老师的《.NET 4.0面向对象编程漫谈》有关代理的内容

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