DOM方式解析xml文件1(解析网路xml)

其实网上很多资料讲关于解析xml的问题,大多数我都看的一知半解,今天终于找了个不错的例子,放在这里跟大家共享:
先上代码:
1.DomParseXml.java文件

package cn.com;

import java.io.File;
import java.io.InputStreamReader;
import java.net.URL;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;

public class DomParseXml extends Activity implements OnClickListener {

	File fl;

        //这个地址返回的内容的xml文件我下面会贴上
        //大家可以先跳过这个java文件看下xml文件结构
	private final String net = "http://www.google.com/ig/api?hl=zh-cn&weather=";

	private String addr;

	ListView lv;

	ArrayAdapter<String> adapter;

	private EditText et;

	@Override
	public void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.main);

		Button bt = (Button) findViewById(R.id.bt);

		bt.setOnClickListener(this);
                //输入一个城市(wuhan或beijing等)
		et = (EditText) findViewById(R.id.et);

	}

	@Override
	public void onClick(View agr0) {

		// TODO Auto-generated method stub

		addr = et.getText().toString();

		switch (agr0.getId()) {

		case R.id.bt:
			// 获取输入的内容,取出空格
			if (!addr.trim().equals("")) {

				addr = net + addr;
				// System.out.println(addr);

				String[] data = null;
				// 将weather设置为根节点
				// Node nRoot = root(addr,"weather").item(0);
                                // 这里返回的是一个NodeList
				Node nRoot = root(addr, "forecast_information").item(0);
				// 获得孩子结点
				NodeList child = nRoot.getChildNodes();
				// 获得子节点的个数 7
				int childSize = child.getLength();
				System.out.println("**********childSize************"
						+ childSize);

				data = new String[childSize];

				for (int i = 0; i < childSize; i++) {
					// 第一个子节点,city
					Node nChild = child.item(i);
					// 获得子节点
					if (nChild.hasAttributes()) {
						// 获得节点属性
						data[i] = nChild.getAttributes().getNamedItem("data")
								.getNodeValue();
						System.out.println("**********************" + data[i]);

					}
				}
			}
			setTitle(et.getText().toString()); // 显示查询的城市
			break;
		}
	}

	private NodeList root(final String url, final String str) {

		NodeList root = null;

		try {

			InputSource is = new InputSource(new InputStreamReader(new URL(url)
					.openStream()));

			DocumentBuilderFactory factory = DocumentBuilderFactory
					.newInstance();

			DocumentBuilder dom = factory.newDocumentBuilder();

			Document doc = dom.parse(is);

			root = doc.getElementsByTagName(str);

		} catch (Exception e) {

			e.printStackTrace();

		}

		return root;

	}

}

2.main.xml文件内容:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical" android:layout_width="fill_parent"
	android:layout_height="fill_parent">
	<TextView android:layout_width="fill_parent"
		android:layout_height="wrap_content" android:text="@string/hello" />
	<EditText android:text="" android:id="@+id/et"
		android:layout_width="150dp" android:layout_height="wrap_content"></EditText>
	<Button android:text="button" android:id="@+id/bt"
		android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
</LinearLayout>

3.每次都强调下的一条:

<uses-permission android:name="android.permission.INTERNET">
	</uses-permission>

另外我经常遇到在启动模拟器的时候那个模拟器连不上互联网,那个右上角的信号图标是个叉,我也不知道怎么修改,重新启动了下模拟器后就又可以联网了.不知道是什么原因,我们这种联网的应用如果在测试的时候没有注意到这的话,程序就会报错,说:
can't reach the host之类的,哪位兄弟姐妹知道是什么原因的话,麻烦告知一下,谢谢
另外附上查询到的xml文件:

<?xml version="1.0" ?> 
- <xml_api_reply version="1">
- <weather module_id="0" tab_id="0" mobile_row="0" mobile_zipped="1" row="0" section="0">
- <forecast_information>
  <city data="Beijing, Beijing" /> 
  <postal_code data="beijing" /> 
  <latitude_e6 data="" /> 
  <longitude_e6 data="" /> 
  <forecast_date data="2010-07-01" /> 
  <current_date_time data="2010-07-02 00:00:00 +0000" /> 
  <unit_system data="SI" /> 
  </forecast_information>
- <current_conditions>
  <condition data="晴" /> 
  <temp_f data="73" /> 
  <temp_c data="23" /> 
  <humidity data="湿度： 83%" /> 
  <icon data="/ig/images/weather/sunny.gif" /> 
  <wind_condition data="风向： 北、风速：4 米/秒" /> 
  </current_conditions>
- <forecast_conditions>
  <day_of_week data="周四" /> 
  <low data="21" /> 
  <high data="33" /> 
  <icon data="/ig/images/weather/chance_of_rain.gif" /> 
  <condition data="可能有雨" /> 
  </forecast_conditions>
- <forecast_conditions>
  <day_of_week data="周五" /> 
  <low data="22" /> 
  <high data="33" /> 
  <icon data="/ig/images/weather/sunny.gif" /> 
  <condition data="晴" /> 
  </forecast_conditions>
- <forecast_conditions>
  <day_of_week data="周六" /> 
  <low data="24" /> 
  <high data="33" /> 
  <icon data="/ig/images/weather/mostly_sunny.gif" /> 
  <condition data="以晴为主" /> 
  </forecast_conditions>
- <forecast_conditions>
  <day_of_week data="周日" /> 
  <low data="21" /> 
  <high data="35" /> 
  <icon data="/ig/images/weather/mostly_sunny.gif" /> 
  <condition data="晴间多云" /> 
  </forecast_conditions>
  </weather>
  </xml_api_reply>