接上一章，這一章我們介紹Dom解析，因為Dom是J2EE中用得比較多的解析器，這裡解析方法跟J2EE方法是一樣的，具體的樣式跟以下這篇文章中的樣式是一樣的
<?xml version="1.0" encoding="UTF-8"?>
<persons>
<person id = "1">
<status>大徙弟</status>
<name>孫悟空</name>
<tool>金箍棒</tool>
<number>殺死瞭50隻妖怪</number>
</person>
<person id = "2">
<status>二徙弟</status>
<name>豬八戒</name>
<tool>九齒釘耙</tool>
<number>殺死瞭40隻妖怪</number>
</person>
<person id = "3">
<status>三徙弟</status>
<name>沙和尚</name>
<tool>降妖寶杖</tool>
<number>殺死瞭30隻妖怪</number>
</person>
</persons>
其他數據或樣式請看以下教程
Android[中級教程]第五章XML解析之PULL解析器
我們來看解析處的代碼：
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
{
//通過Dom工廠方法建立Dom解析器
DocumentBuilder builder =DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document document = builder.parse(input);
Element element = document.getDocumentElement();
//取得節點<person>的節點列表
NodeList personNodes =element.getElementsByTagName("person");
//節點長度
int length = personNodes.getLength();
for(int i = 0; i < length; i++){
//取得<person>的節點元素
Element personElement = (Element)personNodes.item(i);
person = new Person();
//取得<person id="1">中的id屬性值
person.setId(personElement.getAttribute("id"));
//繼續向下,取得子節點列表,如<status><name>等等
NodeList childnodes = personElement.getChildNodes();
int len = childnodes.getLength();
for(int j = 0 ; j < len ; j++){
//如果子節點是一個元素節點
if(childnodes.item(j).getNodeType() == Node.ELEMENT_NODE){
//取得節點名稱
String nodeName = childnodes.item(j).getNodeName();
//取得節點值
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;
}
}
接著就是Activity的代碼瞭：
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
{
//自完義適配方法
getAdapter();
} catch (Exception e)
{
e.printStackTrace();
}
listView.setAdapter(adapter);
}
//自定義適配方法
private void getAdapter() throws Exception
{
List<Map<String, String>> lists = new ArrayList<Map<String, String>>();
//這一部分就是剛才我們做測試用的部分
File SD_Files = Environment.getExternalStorageDirectory();
String file_path = SD_Files.getName() + File.separator + "persons.xml";
//PULL解析文檔
// FileInputStream input = new FileInputStream(new File(file_path));
// PullHandler pullHandler = new PullHandler(input);
// List<Person> persons = pullHandler.getPersons();
//SAX解析文檔
// 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解析文檔
FileInputStream fis = new FileInputStream(new File(file_path));
DomHandler domHandler = new DomHandler(fis);
List<Person> persons = domHandler.getPersons();
//將persons中的數據轉換到ArrayList<Map<String, String>>中,因為SimpleAdapter要用這個類型的數據進行適配
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中對應的控件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);
}
}
其實Dom有Android中還是用的比較少的，主要是考慮性能的問題，畢竟手機不比服務器或電腦啊。
下一章，我們將會介紹Json的解析方法，希望各位同學們認真學習。
呵呵，十月長假很快就結束瞭，又要努力工作和學習瞭。謝謝
摘自：kangkangz4的專欄
