接上一章,这一章我们介绍Dom解析,因为Dom是J2EE中用得比较多的解析器,这里解析方法跟J2EE方法是一样的,具体的样式跟以下这篇文章中的样式是一样的
<?xml version="1.0" encoding="UTF-8"?>
<persons>
<person id = "1">
<status>大徙弟</status>
<name>孙悟空</name>
<tool>金箍棒</tool>
<number>杀死了50只妖怪</number>
</person>
<person id = "2">
<status>二徙弟</status>
<name>猪八戒</name>
<tool>九齿钉耙</tool>
<number>杀死了40只妖怪</number>
</person>
<person id = "3">
<status>三徙弟</status>
<name>沙和尚</name>
<tool>降妖宝杖</tool>
<number>杀死了30只妖怪</number>
</person>
</persons>
其他数据或样式请看以下教程
Android[中级教程]第五章XML解析之PULL解析器
我们来看解析处的代码:
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class DomHandler
{
private InputStream input;
private List<Person> persons;
private Person person;
public DomHandler()
{
}
public DomHandler(InputStream input)
{
this.input = input;
}
public void setInput(InputStream input)
{
this.input = input;
}
public List<Person> getPersons(){
persons = new ArrayList<Person>();
try
{
//通过Dom工厂方法建立Dom解析器
DocumentBuilder builder =DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document document = builder.parse(input);
Element element = document.getDocumentElement();
//取得节点<person>的节点列表
NodeList personNodes =element.getElementsByTagName("person");
//节点长度
int length = personNodes.getLength();
for(int i = 0; i < length; i++){
//取得<person>的节点元素
Element personElement = (Element)personNodes.item(i);
person = new Person();
//取得<person id="1">中的id属性值
person.setId(personElement.getAttribute("id"));
//继续向下,取得子节点列表,如<status><name>等等
NodeList childnodes = personElement.getChildNodes();
int len = childnodes.getLength();
for(int j = 0 ; j < len ; j++){
//如果子节点是一个元素节点
if(childnodes.item(j).getNodeType() == Node.ELEMENT_NODE){
//取得节点名称
String nodeName = childnodes.item(j).getNodeName();
//取得节点值
String nodeValue = childnodes.item(j).getFirstChild().getNodeValue();
if("status".equals(nodeName)){
person.setStatus(nodeValue);
}
if("name".equals(nodeName)){
person.setName(nodeValue);
}
if("tool".equals(nodeName)){
person.setTool(nodeValue);
}
if("number".equals(nodeName)){
person.setNumber(nodeValue);
}
}
}//end for j
persons.add(person);
}//end for i
return persons;
} catch (Exception e)
{
e.printStackTrace();
}
return null;
}
}
接着就是Activity的代码了:
import java.io.File;
import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class PullActivity extends Activity
{
private ListView listView;
private SimpleAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState)
{
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.xml_handler);
listView = (ListView)findViewById(R.id.xml_list);
try
{
//自完义适配方法
getAdapter();
} catch (Exception e)
{
e.printStackTrace();
}
listView.setAdapter(adapter);
}
//自定义适配方法
private void getAdapter() throws Exception
{
List<Map<String, String>> lists = new ArrayList<Map<String, String>>();
//这一部分就是刚才我们做测试用的部分
File SD_Files = Environment.getExternalStorageDirectory();
String file_path = SD_Files.getName() + File.separator + "persons.xml";
//PULL解析文档
// FileInputStream input = new FileInputStream(new File(file_path));
// PullHandler pullHandler = new PullHandler(input);
// List<Person> persons = pullHandler.getPersons();
//SAX解析文档
// FileInputStream fis = new FileInputStream(new File(file_path));
// SAXParser parser = SAXParserFactory.newInstance().newSAXParser();
// SaxHandler saxHandler = new SaxHandler();
// parser.parse(fis, saxHandler);
// List<Person> persons = saxHandler.getPersons();
//Dom解析文档
FileInputStream fis = new FileInputStream(new File(file_path));
DomHandler domHandler = new DomHandler(fis);
List<Person> persons = domHandler.getPersons();
//将persons中的数据转换到ArrayList<Map<String, String>>中,因为SimpleAdapter要用这个类型的数据进行适配
Map<String, String> map;
for(Person p : persons){
map = new HashMap<String, String>();
map.put("id", p.getId());
map.put("status", p.getStatus());
map.put("name", p.getName());
map.put("tool", p.getTool());
map.put("number", p.getNumber());
lists.add(map);
}
//HashMap<String, String>中的key
String[] from = {"id", "status", "name", "tool", "number"};
//list_item.xml中对应的控件ID
int[] to = {R.id.item_id, R.id.item_status, R.id.item_name, R.id.item_tool, R.id.item_number};
adapter = new SimpleAdapter(this, lists, R.layout.handler_list_item, from, to);
}
}
其实Dom有Android中还是用的比较少的,主要是考虑性能的问题,毕竟手机不比服务器或电脑啊。
下一章,我们将会介绍Json的解析方法,希望各位同学们认真学习。
呵呵,十月长假很快就结束了,又要努力工作和学习了。谢谢
摘自:kangkangz4的专栏