Android 通过WebService进行网络编程，使用工具类轻松实现

相信大家在平常的开发中，对网络的操作用到HTTP协议比较多，通过我们使用Get或者Post的方法调用一个数据接口，然后服务器给我们返回JSON格式的数据，我们解析JSON数据然后展现给用户，相信很多人很喜欢服务器给我们返回JSON数据格式，因为他解析方便，也有一些JSON的解析库，例如Google提供的GSON，阿里巴巴的FastJson,不过还是推荐大家使用FastJson来解析，我自己开发中也是用FastJson来解析，FastJson的介绍http://code.alibabatech.com/wiki/display/FastJSON/Home，不过有时候我们用到WebService接口来获取数据，  WebService是一种基于SOAP协议的远程调用标准，通过webservice可以将不同操作系统平台、不同语言、不同技术整合到一块。在Android SDK中并没有提供调用WebService的库，因此，需要使用第三方的SDK来调用WebService。PC版本的WEbservice客户端库非常丰富，例如Axis2，CXF等，但这些开发包对于Android系统过于庞大，也未必很容易移植到Android系统中。因此，这些开发包并不是在我们的考虑范围内。适合手机的WebService客户端的SDK有一些，比较常用的有Ksoap2，可以从http://code.google.com/p/ksoap2-android/wiki/HowToUse?tm=2进行下载，将jar包加入到libs目录下就行了，接下来带大家来调用WebService接口

首先我们新建一个工程，取名WebServiceDemo,我们从http://www.webxml.com.cn/zh_cn/web_services.aspx来获取WebService接口，这里面有一些免费的WebService接口，我们就用里面的天气接口吧http://www.webxml.com.cn/WebServices/WeatherWebService.asmx

我们新建一个WebService的工具类，用于对WebService接口的调用，以后遇到调用WebService直接拷贝来用就行了

package com.example.webservicedemo;

import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpResponseException;
import org.ksoap2.transport.HttpTransportSE;
import org.xmlpull.v1.XmlPullParserException;

import android.os.Handler;
import android.os.Message;

/**
 * 访问WebService的工具类,
 * 
 * @see http://blog.csdn.net/xiaanming
 * 
 * @author xiaanming
 * 
 */
public class WebServiceUtils {
	public static final String WEB_SERVER_URL = "http://www.webxml.com.cn/WebServices/WeatherWebService.asmx";
	
	
	// 含有3个线程的线程池
	private static final ExecutorService executorService = Executors
			.newFixedThreadPool(3);

	// 命名空间
	private static final String NAMESPACE = "http://WebXml.com.cn/";

	/**
	 * 
	 * @param url
	 *            WebService服务器地址
	 * @param methodName
	 *            WebService的调用方法名
	 * @param properties
	 *            WebService的参数
	 * @param webServiceCallBack
	 *            回调接口
	 */
	public static void callWebService(String url, final String methodName,
			HashMap<String, String> properties,
			final WebServiceCallBack webServiceCallBack) {
		// 创建HttpTransportSE对象，传递WebService服务器地址
		final HttpTransportSE httpTransportSE = new HttpTransportSE(url);
		// 创建SoapObject对象
		SoapObject soapObject = new SoapObject(NAMESPACE, methodName);

		// SoapObject添加参数
		if (properties != null) {
			for (Iterator<Map.Entry<String, String>> it = properties.entrySet()
					.iterator(); it.hasNext();) {
				Map.Entry<String, String> entry = it.next();
				soapObject.addProperty(entry.getKey(), entry.getValue());
			}
		}

		// 实例化SoapSerializationEnvelope，传入WebService的SOAP协议的版本号
		final SoapSerializationEnvelope soapEnvelope = new SoapSerializationEnvelope(
				SoapEnvelope.VER11);
		// 设置是否调用的是.Net开发的WebService
		soapEnvelope.setOutputSoapObject(soapObject);
		soapEnvelope.dotNet = true;
		httpTransportSE.debug = true;

		// 用于子线程与主线程通信的Handler
		final Handler mHandler = new Handler() {

			@Override
			public void handleMessage(Message msg) {
				super.handleMessage(msg);
				// 将返回值回调到callBack的参数中
				webServiceCallBack.callBack((SoapObject) msg.obj);
			}

		};

		// 开启线程去访问WebService
		executorService.submit(new Runnable() {

			@Override
			public void run() {
				SoapObject resultSoapObject = null;
				try {
					httpTransportSE.call(NAMESPACE + methodName, soapEnvelope);
					if (soapEnvelope.getResponse() != null) {
						// 获取服务器响应返回的SoapObject
						resultSoapObject = (SoapObject) soapEnvelope.bodyIn;
					}
				} catch (HttpResponseException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				} catch (XmlPullParserException e) {
					e.printStackTrace();
				} finally {
					// 将获取的消息利用Handler发送到主线程
					mHandler.sendMessage(mHandler.obtainMessage(0,
							resultSoapObject));
				}
			}
		});
	}

	/**
	 * 
	 * 
	 * @author xiaanming
	 * 
	 */
	public interface WebServiceCallBack {
		public void callBack(SoapObject result);
	}

}

我们通过调用里面的callWebService(String url, final String methodName,HashMap<String, String> properties,final WebServiceCallBack webServiceCallBack)就可以来获取我们想要的数据，现在讲解下里面的实现思路

• 创建HttpTransportsSE对象。通过HttpTransportsSE类的构造方法可以指定WebService的WSDL文档的URL
• 创建SoapObject对象，里面的参数分别是WebService的命名空间和调用方法名
• 设置调用方法的参数值，如果没有参数，就不设置，有参数的话调用SoapObject对象的addProperty(String name, Object value)方法将参数加入到SoapObject对象中
• 实例化SoapSerializationEnvelope，传入WebService的SOAP协议的版本号，将上面的SoapObject对象通过setOutputSoapObject(Object soapObject)设置到里面，并设置是否调用的是.Net开发的WebService和是否debug等信息
• 因为涉及到网络操作，所以我们使用了线程池来异步操作调用WebService接口，我们在线程中调用HttpTransportsSE对象的call(String soapAction, SoapEnvelope envelope)方法就能实现对WebService的调用，并且通过soapEnvelope.bodyIn获取WebService返回的信息，但是返回的信息是在子线程中，我们需要利用Handler来实现子线程与主线程进行转换，然后在Handler的handleMessage(Message msg)中将结果回调到callBack的参数中，总体思路就是这个样子，接下来我们来使用这个工具类吧

我们先用一个ListView来显示所有的省份，然后点击每个省进去到市。市也用一个ListView来显示，最后点击市用TextView来显示获取的WebService天气情况，思路很简单

用来显示省份的布局，里面只有一个ListView

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <ListView
        android:id="@+id/province_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:cacheColorHint="@android:color/transparent"
        android:fadingEdge="none" >
    </ListView>

</RelativeLayout>

接下来就是Activity的代码，先用工具类调用WebService方法，然后在回调方法callBack(SoapObject result)中解析数据到一个List<String>中，在设置ListView的适配器

package com.example.webservicedemo;

import java.util.ArrayList;
import java.util.List;

import org.ksoap2.serialization.SoapObject;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import com.example.webservicedemo.WebServiceUtils.WebServiceCallBack;

/**
 * 显示天气省份的Activity
 * 
 * @see http://blog.csdn.net/xiaanming
 * 
 * @author xiaanming
 *
 */
public class MainActivity extends Activity {
	private List<String> provinceList = new ArrayList<String>();

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		init();
	}

	private void init() {
		final ListView mProvinceList = (ListView) findViewById(R.id.province_list);
		
		//显示进度条
		ProgressDialogUtils.showProgressDialog(this, "数据加载中...");
		
		//通过工具类调用WebService接口
		WebServiceUtils.callWebService(WebServiceUtils.WEB_SERVER_URL, "getSupportProvince", null, new WebServiceCallBack() {
			
			//WebService接口返回的数据回调到这个方法中
			@Override
			public void callBack(SoapObject result) {
				//关闭进度条
				ProgressDialogUtils.dismissProgressDialog();
				if(result != null){
					provinceList = parseSoapObject(result);
					mProvinceList.setAdapter(new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1, provinceList));
				}else{
					Toast.makeText(MainActivity.this, "获取WebService数据错误", Toast.LENGTH_SHORT).show();
				}
			}
		});
		
		mProvinceList.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				Intent intent = new Intent(MainActivity.this, CityActivity.class);
				intent.putExtra("province", provinceList.get(position));
				startActivity(intent);
				
			}
		});
		
		
	}
	
	/**
	 * 解析SoapObject对象
	 * @param result
	 * @return
	 */
	private List<String> parseSoapObject(SoapObject result){
		List<String> list = new ArrayList<String>();
		SoapObject provinceSoapObject = (SoapObject) result.getProperty("getSupportProvinceResult");
		if(provinceSoapObject == null) {
			return null;
		}
		for(int i=0; i<provinceSoapObject.getPropertyCount(); i++){
			list.add(provinceSoapObject.getProperty(i).toString());
		}
		
		return list;
	}

}

点击省份进入该省份下面的市。也用一个ListView来显示市的数据，布局跟上面一样，Activity里面的代码也差不多相似，我就不过多说明了，直接看代码

package com.example.webservicedemo;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.ksoap2.serialization.SoapObject;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import com.example.webservicedemo.WebServiceUtils.WebServiceCallBack;

/**
 * 显示城市的Activity
 * 
 * @see http://blog.csdn.net/xiaanming
 * 
 * @author xiaanming
 *
 */
public class CityActivity extends Activity {
	private List<String> cityStringList;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		init();
	}

	private void init() {
		final ListView mCityList = (ListView) findViewById(R.id.province_list);
		
		//显示进度条
		ProgressDialogUtils.showProgressDialog(this, "数据加载中...");
		
		//添加参数
		HashMap<String, String> properties = new HashMap<String, String>();
		properties.put("byProvinceName", getIntent().getStringExtra("province"));
		
		WebServiceUtils.callWebService(WebServiceUtils.WEB_SERVER_URL, "getSupportCity", properties, new WebServiceCallBack() {
			
			@Override
			public void callBack(SoapObject result) {
				ProgressDialogUtils.dismissProgressDialog();
				if(result != null){
					cityStringList = parseSoapObject(result);
					mCityList.setAdapter(new ArrayAdapter<String>(CityActivity.this, android.R.layout.simple_list_item_1, cityStringList));
				}else{
					Toast.makeText(CityActivity.this, "获取WebService数据错误", Toast.LENGTH_SHORT).show();
				}
			}
		});
		
		mCityList.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				Intent intent = new Intent(CityActivity.this, WeatherActivity.class);
				intent.putExtra("city", cityStringList.get(position));
				startActivity(intent);
			}
		});
	}
	
	/**
	 * 解析SoapObject对象
	 * @param result
	 * @return
	 */
	private List<String> parseSoapObject(SoapObject result){
		List<String> list = new ArrayList<String>();
		SoapObject provinceSoapObject = (SoapObject) result.getProperty("getSupportCityResult");
		for(int i=0; i<provinceSoapObject.getPropertyCount(); i++){
			String cityString = provinceSoapObject.getProperty(i).toString();
			list.add(cityString.substring(0, cityString.indexOf("(")).trim());
		}
		
		return list;
	}
}

接下来就是点击相对应的城市调用WebService接口来获取该城市下面的天气详情啦，为了简单起见，我用一个TextView来显示天气信息，因为天气信息很多，一个屏幕显示不完，所以我们考虑在外面加一个ScrollView来进行滚动

<?xml version="1.0" encoding="UTF-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ScrollView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent" >

            <TextView
                android:id="@+id/weather"
                android:textColor="#336598"
                android:textSize="16sp"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />
        </LinearLayout>
    </ScrollView>

</RelativeLayout>

Activity的代码就不做过多说明，跟上面的大同小异

package com.example.webservicedemo;

import java.util.HashMap;

import org.ksoap2.serialization.SoapObject;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

import com.example.webservicedemo.WebServiceUtils.WebServiceCallBack;

/**
 * 显示天气的Activity
 * 
 * @see http://blog.csdn.net/xiaanming
 * 
 * @author xiaanming
 *
 */
public class WeatherActivity extends Activity{
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.weather_layout);
		init();
	}

	private void init() {
		final TextView mTextWeather = (TextView) findViewById(R.id.weather);
		ProgressDialogUtils.showProgressDialog(this, "数据加载中...");
		HashMap<String, String> properties = new HashMap<String, String>();
		properties.put("theCityName", getIntent().getStringExtra("city"));
		
		WebServiceUtils.callWebService(WebServiceUtils.WEB_SERVER_URL, "getWeatherbyCityName", properties, new WebServiceCallBack() {
			
			@Override
			public void callBack(SoapObject result) {
				ProgressDialogUtils.dismissProgressDialog();
				if(result != null){
					SoapObject detail = (SoapObject) result.getProperty("getWeatherbyCityNameResult");
					StringBuilder sb = new StringBuilder();
					for(int i=0; i<detail.getPropertyCount(); i++){
						sb.append(detail.getProperty(i)).append("\r\n");
					}
					mTextWeather.setText(sb.toString());
				}else{
					Toast.makeText(WeatherActivity.this, "获取WebService数据错误", Toast.LENGTH_SHORT).show();
				}
			}
		});
	}
}

到这里我们就完成了编码工作，在运行程序之前我们需要在AndroidManifest.xml注册Activity，以及添加访问网络的权限

<application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.webservicedemo.MainActivity"
            android:label="@string/title_activity_main" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".CityActivity"/>
        <activity android:name=".WeatherActivity"></activity>
    </application>
    
    <uses-permission android:name="android.permission.INTERNET"/>

运行结果：