Android开发WeatherForecast程序

1，使用Googel API
http://www.google.com/ig/api?&weather=beijing

2，使用DOM解析XML

 

String weather = "";  String url = "[url=http://www.google.com/ig/api?&weather=beijing]http://www.google.com/ig/api?&weather=beijing[/url]";     DefaultHttpClient client = new DefaultHttpClient();  HttpUriRequest req = new HttpGet(url);  HttpResponse resp = client.execute(req);  HttpEntity ent = resp.getEntity();     InputStream stream = ent.getContent();  DocumentBuilder b = DocumentBuilderFactory.newInstance().newDocumentBuilder();  Document d = b.parse(new InputSource(stream));   NodeList n = d.getElementsByTagName("forecast_conditions");  for (int i = 0; i < n.getLength(); i++) {   weather += n.item(i).getChildNodes().item(0).getAttributes().item(0).getNodeValue();  weather += ", ";  weather += (Integer.parseInt(n.item(i).getChildNodes().item(1).getAttributes().item(0).getNodeValue()) - 32) * 5 / 9;   weather += " ~ ";  weather += (Integer.parseInt(n.item(i).getChildNodes().item(2).getAttributes().item(0).getNodeValue()) - 32) * 5 / 9;  weather += ", ";   weather += n.item(i).getChildNodes().item(4).getAttributes().item(0).getNodeValue();   weather += "\n";  }

 

3，另起Thread处理Web请求

new Thread() {     public void run() {     try {        // ...     } catch (Exception e) {      e.printStackTrace();     }   }     }.start();   

 

 

4，使用Handler传递Thread处理结果到UI主Thread

 

h = new Handler() {  public void handleMessage(Message msg) {    tv.setText((String)msg.obj);  }  };     new Thread() {  // ...  Message msg = h.obtainMessage(1, 1, 1, weather);  h.sendMessage(msg);  }

 

5，完整代码

package com.hideto.weatherforecast;     import java.io.InputStream;  import javax.xml.parsers.DocumentBuilder;  import javax.xml.parsers.DocumentBuilderFactory;  import org.apache.http.HttpEntity;  import org.apache.http.HttpResponse;  import org.apache.http.client.methods.HttpGet;  import org.apache.http.client.methods.HttpUriRequest;  import org.apache.http.impl.client.DefaultHttpClient;  import org.w3c.dom.Document;  import org.w3c.dom.NodeList;  import org.xml.sax.InputSource;  import android.app.Activity;  import android.os.Bundle;  import android.os.Handler;  import android.os.Message;  import android.widget.TextView;     public class WeatherForecast extends Activity {  public TextView tv;  public Handler h;     @Override   public void onCreate(Bundle savedInstanceState) {       super.onCreate(savedInstanceState);    tv = new TextView(this);    tv.setText("Loading...");    setContentView(tv);    h = new Handler() {     public void handleMessage(Message msg) {      tv.setText((String)msg.obj);     }    };    new Thread() {     public void run() {      try {  
     String weather = "";       String url = "[url=http://www.google.com/ig/api?&weather=beijing]http://www.google.com/ig/api?&weather=beijing[/url]";       DefaultHttpClient client = new DefaultHttpClient();       HttpUriRequest req = new HttpGet(url);       HttpResponse resp = client.execute(req);       HttpEntity ent = resp.getEntity();       InputStream stream = ent.getContent();       DocumentBuilder b = DocumentBuilderFactory.newInstance().newDocumentBuilder();       Document d = b.parse(new InputSource(stream));       NodeList n = d.getElementsByTagName("forecast_conditions");  
     for (int i = 0; i < n.getLength(); i++) {        weather += n.item(i).getChildNodes().item(0).getAttributes().item(0).getNodeValue();
      weather += ", ";        weather += (Integer.parseInt(n.item(i).getChildNodes().item(1).getAttributes().item(0).getNodeValue()) - 32) * 5 / 9;  　　　 weather += " ~ ";
      weather += (Integer.parseInt(n.item(i).getChildNodes().item(2).getAttributes().item(0).getNodeValue()) - 32) * 5 / 9;   　　  weather += ", ";        weather += n.item(i).getChildNodes().item(4).getAttributes().item(0).getNodeValue();        weather += "\n";       }       Message msg = h.obtainMessage(1, 1, 1, weather);       h.sendMessage(msg);      } catch (Exception e) {       e.printStackTrace();      }     }    }.start();    }     }

 

6，修改AndroidManifest.xml加上INTERNET访问权限

 

<?xml version="1.0" encoding="utf-8"?>     <manifest xmlns:android="[url=http://schemas.android.com/apk/res/android]http://schemas.android.com/apk/res/android[/url]"         package="com.hideto.weatherforecast"         android:versionCode="1"         android:versionName="1.0.0">       <uses-permission android:name="android.permission.INTERNET"></uses-permission>       <application android:icon="@drawable/icon" android:label="@string/app_name">           <activity android:name=".WeatherForecast"                     android:label="@string/app_name">               <intent-filter>                  <action android:name="android.intent.action.MAIN" />                   <category android:name="android.intent.category.LAUNCHER" />               </intent-filter>           </activity>       </application>   </manifest>