接上一章,這一章我們就來學習SAX解析器,其實SAX跟PULL解析器差不多,事實上學會和掌握一種XML解析器對於完成項目來說已經足夠瞭,當然,多學一點也不是什麼壞事,你說呢?呵呵,加油哦!我們還是以唐僧師徙的數據為例
<?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>
xml文件跟上一章的一樣,如果不清楚的話可以參考一下上一章
Android[中級教程]第五章XML解析之PULL解析器
這裡我就主要放上SAXHandler的源碼瞭
import java.util.ArrayList;
import java.util.List;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class SaxHandler extends DefaultHandler
{
private List<Person> persons;
private Person person;
private String tagName;//作用是記錄解析時的上一個節點名稱
public List<Person> getPersons(){
return persons;
} www.aiwalls.com
/**
* 節點處理
*/
@Override
public void characters(char[] ch, int start, int length)
throws SAXException
{
String data = new String(ch, start, length);
if("status".equals(tagName)){
person.setStatus(data);
}
if("name".equals(tagName)){
person.setName(data);
}
if("tool".equals(tagName)){
person.setTool(data);
}
if("number".equals(tagName)){
person.setNumber(data);
}
}
/**
* 元素結束
*/
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException
{
if("person".equals(localName)){
persons.add(person);
person = null;
}
tagName = null;
}
/**
* 文檔開始
*/
@Override
public void startDocument() throws SAXException
{
persons = new ArrayList<Person>();
}
/**
* 元素開始
*/
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException
{
if("person".equals(localName)){
person = new Person();
person.setId(attributes.getValue("id"));
}
tagName = localName;//將正在解析的節點名稱賦給tagName
}
}
接著就是Activity中的源碼:
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 javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
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";
// FileInputStream input = new FileInputStream(new File(file_path));
// PullHandler pullHandler = new PullHandler(input);
// List<Person> persons = pullHandler.getPersons();
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();
//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);
}
}
其他的跟PULL解析都一樣的,這裡隻是將PULL解析換成瞭SAX解析,在源碼中就是把中間的三行代碼換成瞭SAX解析的代碼,上圖:
看,都是一樣的,下一章要介紹DOM解析器瞭,希望大傢能好好學習,謝謝
摘自:kangkangz4的專欄