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>