andoird --- XmlPullParser 的使用

有个升级项目需要使用到xml文件，由于XmlPullParser最简单所以选择它也完全满足当前的需求应用。
下面就简要的说明一下具体的用法。

1、基本原理：
常用的有：
XmlPullParser.END_DOCUMENT
XmlPullParser.START_DOCUMENT
XmlPullParser.START_TAG
XmlPullParser.END_TAG
XmlPullParser.TEXT 
分别代表着XML文档的结束，开始，标签的开始，标签的结束，内容 

按照以上的格式依次进行解析即可。

2、介绍了三种不同的xml格式及解析方法

新建一个新的activiy文件，其实就是程序启动发源地而已。

public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);        
        xmltest xl = new xmltest();
        xl.test(getResources());
    }
   }

为了便于xml解析内容的存取，新建了一个Person.java类,内容如下：

package com.test.xmlactivity;

class Person{
	private int id = -1;
	private int age = 0;
	private String name = null;
	private String title = null;
	
	public Person(){
		//TODO
	}
	
	public Person(int _id,int _age,String _name,String _title){
		this.id = _id ;
		this.age = _id;
		this.name = _name;
		this.title = _title;
	}
	
	public void setID(int id){
		this.id = id;
	}
	
	public int getID(){
		return this.id;
	}
	
	public void setAge(int age){
		this.age = age;
	}
	
	public int getAge(){
		return this.age;
	}
	
	public void setName(String name){
		this.name = name;
	}
	
	public String getName(){
		return this.name;
	}
	
	public void setTitle(String title){
		this.title = title;
	}
	
	public String getTitle(){
		return this.title;
	}
};

为方便其它程序简洁使用xml的读取及解析，封装了一个xmlReader.java类，内容如下：

package com.test.xmlactivity;

import java.io.IOException;
import java.io.StringReader;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;

import android.util.Log;

class XmlReader{
	private final static String TAG = "XmlReader";
	private XmlPullParser xmlparser = null;
	public static final String charset = "utf-8";
	
	public XmlReader(){
		try {
			XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
			factory.setNamespaceAware(true);
			xmlparser = factory.newPullParser();
		} catch (Exception e) {
			e.printStackTrace();
			Log.e(TAG,"create xml reader failed");
		}
	}

	public void setXML(String xml) throws IOException{
		try {
			xmlparser.setInput(new StringReader(xml));
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
		
	public int getNextEvent() throws IOException {
		try {
			return xmlparser.next(); 
		} catch (Exception e) {
			e.printStackTrace();
		}
		return -1;
	}
	
	public String getNextText() throws IOException{
		try {
			return xmlparser.nextText();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}
	
	public int getEventType() throws IOException {
		try {
			return xmlparser.getEventType();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return -1;
	}
	
	public String getName() {
		return xmlparser.getName();
	}
	
	public String getText() {
		return xmlparser.getText();
	}	
	
	public int attributeCount() {
		return xmlparser.getAttributeCount();
	}

	public String getAttributeName(int i) {
		return xmlparser.getAttributeName(i);
	}

	public String getAttributeValue(String name) {
		String v = xmlparser.getAttributeValue(null, name);
		return v;
	}
	
	public int getDepth() {
		return xmlparser.getDepth();
	}
};

需要读取的xml资源文件放在 res\xm;\person.xml,其具体内容如下：

<?xml version="1.0" encoding="utf-8"?>
<White-collars>
	<employee id="1">
		<name>tom</name>
		<age>25</age>
		<title>engineer</title>
	</employee>

	<employee  id="2">
		<name>kite</name>
		<age>21</age>
		<title>tester</title>
	</employee>

	<employee id="3">
		<name>rose</name>
		<age>28</age>
		<title>manager</title>
	</employee>

</White-collars>

a、从资源文件中读取
需要使用系统资源，必须有Context对象，而Activity可以持有，所以需要在测试前将其资源句柄传入
xl.test(getResources());
而在具体的类中记录下来即可使用
private XmlReader XR = null;
private ArrayList<Person> mperlist = new ArrayList<Person>();
private Resources mRes = null;

public void test(Resources _res){
this.mRes = _res;
xml_test_main();
}


下面说明一下具体的xml内容解析：

	/* 1、使用文件测试 */
	private void xml_file_test(){
		int eventType = -1;
		Person ps = null;	
		XmlResourceParser xrp = mRes.getXml(R.xml.personal);		
		
		try {
			eventType = xrp.getEventType();
			while (eventType != XmlPullParser.END_DOCUMENT) {
				switch (eventType) {
				case XmlPullParser.START_DOCUMENT:
					break;
				case XmlPullParser.END_DOCUMENT:
					break;
				case XmlPullParser.START_TAG: {
					String tagName = xrp.getName();
					if (tagName != null && tagName.equals("employee")) {
						ps = new Person();
						int id = Integer.parseInt(xrp.getAttributeValue(null, "id"));
						ps.setID(id);
					}

					if (tagName != null && tagName.equals("name")) {
						String name;
						try {
							name = xrp.nextText();;
							ps.setName(name);
						} catch (IOException e) {
							e.printStackTrace();
						}
					}

					if (tagName != null && tagName.equals("title")) {
						String title;
						try {
							title = xrp.nextText();
							ps.setTitle(title);
						} catch (IOException e) {
							e.printStackTrace();
						}
					}

					if (tagName != null && tagName.equals("age")) {
						String age;
						try {
							age = xrp.nextText();
							ps.setAge(Integer.parseInt(age));
						} catch (IOException e) {
							e.printStackTrace();
						}
					}
				}
					break;
				case XmlPullParser.END_TAG: {
					if (xrp.getName().equals("employee")) {
						mperlist.add(ps);
					}
				}
					break;
				case XmlPullParser.TEXT:
					break;
				default:
					break;
				}

				eventType = xrp.next();
			}
		} catch (Exception e) {
			// TODO: handle exception
		}
		
		for(int i=0;i<mperlist.size();i++){
			Log.i(TAG,"person info ====");
			Log.i(TAG,"ID = " + mperlist.get(i).getID());	
			Log.i(TAG,"name = "+ mperlist.get(i).getName());
			Log.i(TAG,"age = " + mperlist.get(i).getAge());	
			Log.i(TAG,"title = " + mperlist.get(i).getTitle());
		}
	}

相应的打印内容：
10-02 10:47:50.725: I/xmltest(12364): person info ====
10-02 10:47:51.094: I/xmltest(12364): ID = 1
10-02 10:47:51.382: I/xmltest(12364): name = tom
10-02 10:47:51.647: I/xmltest(12364): age = 25
10-02 10:47:51.986: I/xmltest(12364): title = engineer
10-02 10:48:03.057: I/xmltest(12364): person info ====
10-02 10:48:03.057: I/xmltest(12364): ID = 2
10-02 10:48:03.057: I/xmltest(12364): name = kite
10-02 10:48:03.057: I/xmltest(12364): age = 21
10-02 10:48:03.057: I/xmltest(12364): title = tester
10-02 10:48:05.038: I/xmltest(12364): person info ====
10-02 10:48:05.038: I/xmltest(12364): ID = 3
10-02 10:48:05.038: I/xmltest(12364): name = rose
10-02 10:48:05.038: I/xmltest(12364): age = 28
10-02 10:48:05.038: I/xmltest(12364): title = manager


b、直接从内存中读取

	/* 直接使用内存测试 */
	private void xml_memory_test(){
		String xml_test = "<foo>Hello World!</foo>";
		try {
			XR.setXML(xml_test);

			int eventType = XR.getEventType();
			Log.i(TAG,"eventType: " + eventType);
			while (eventType != XmlPullParser.END_DOCUMENT) {
				if (eventType == XmlPullParser.START_DOCUMENT) {
					Log.i(TAG,"Start document");
				} else if (eventType == XmlPullParser.START_TAG) {
					Log.i(TAG,"Start tag " + XR.getName());
				} else if (eventType == XmlPullParser.END_TAG) {
					Log.i(TAG,"End tag " + XR.getName());
				} else if (eventType == XmlPullParser.TEXT) {
					Log.i(TAG,"Text " + XR.getText());
				}
				eventType = XR.getNextEvent();
				Log.i(TAG,"eventType: " + eventType);
			}
			Log.i(TAG,"End document");			
		} catch (Exception e) {
			e.printStackTrace();
		}
		return ;
	}

输出内容：
10-02 10:48:07.975: I/xmltest(12364): eventType: 0
10-02 10:48:07.975: I/xmltest(12364): Start document
10-02 10:48:07.983: I/xmltest(12364): eventType: 2
10-02 10:48:07.983: I/xmltest(12364): Start tag foo
10-02 10:48:07.991: I/xmltest(12364): eventType: 4
10-02 10:48:07.999: I/xmltest(12364): Text Hello World!
10-02 10:48:07.999: I/xmltest(12364): eventType: 3
10-02 10:48:07.999: I/xmltest(12364): End tag foo
10-02 10:48:08.006: I/xmltest(12364): eventType: 1
10-02 10:48:08.006: I/xmltest(12364): End document

c、另外的xml格式用法

	/* 另类xml文件写法 */
	private void xml_misc_test(){
		String xml_test = "<foo hi=\"Hello World!\"/>";
		try {
			XR.setXML(xml_test);

			int eventType = XR.getEventType();
			Log.i(TAG,"eventType: " + eventType);
			while (eventType != XmlPullParser.END_DOCUMENT) {
				if (eventType == XmlPullParser.START_DOCUMENT) {
					Log.i(TAG,"Start document");
				} else if (eventType == XmlPullParser.START_TAG) {
					Log.i(TAG,"Start tag " + XR.getName());
					String name = XR.getAttributeName(0);
					String value = XR.getAttributeValue(name);
					Log.i(TAG,"name:" + name + " value:" + value);
				} else if (eventType == XmlPullParser.END_TAG) {
					Log.i(TAG,"End tag " + XR.getName());
				} else if (eventType == XmlPullParser.TEXT) {
					Log.i(TAG,"Text " + XR.getText());
				}
				eventType = XR.getNextEvent();
				Log.i(TAG,"eventType: " + eventType);
			}
			Log.i(TAG,"End document");			
		} catch (Exception e) {
			e.printStackTrace();
		}
		return ;
	}

输出内容:
10-02 10:48:08.014: I/xmltest(12364): eventType: 0
10-02 10:48:08.014: I/xmltest(12364): Start document
10-02 10:48:08.014: I/xmltest(12364): eventType: 2
10-02 10:48:08.014: I/xmltest(12364): Start tag foo
10-02 10:48:08.014: I/xmltest(12364): name:hi value:Hello World!
10-02 10:48:08.014: I/xmltest(12364): eventType: 3
10-02 10:48:08.014: I/xmltest(12364): End tag foo
10-02 10:48:08.014: I/xmltest(12364): eventType: 1
10-02 10:48:08.014: I/xmltest(12364): End document