Android 登陆功能的实现（访问WebServices 解析返回的JSON结果）

1、 WebServices返回的JSON结果

{
    "Code": ,
    "Result": [{
        "ID": "",
        "UserName": "",
        "UserPwd": "",
        "IsEnable": ""
    }]
}

2、访问WEB服务代码

 import android.os.Bundle;
 import android.os.Message;
 import android.util.Log;
 import android.widget.Toast;

 import com.google.gson.Gson;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonParser;
 import com.google.gson.reflect.TypeToken;

 import org.apache.http.HttpResponse;
 import org.apache.http.client.entity.UrlEncodedFormEntity;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.impl.client.DefaultHttpClient;
 import org.apache.http.message.BasicNameValuePair;
 import org.apache.http.protocol.HTTP;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;

 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.util.ArrayList;
 import java.util.List;

 import static java.net.Proxy.Type.HTTP;
 //判读账号、密码
 public static String GetUsers(String code, String pwd) {
         String result = "";
         InputStreamReader in = null;
         try {
             final String SERVER_URL = GlobalAppliaction.WebUrl + "LogIn"; // 定义需要获取的内容来源地址
             HttpPost request = new HttpPost(SERVER_URL); // 根据内容来源地址创建一个Http请求

             List params = new ArrayList();
             params.add(new BasicNameValuePair("username", code)); // 添加必须的参数
             params.add(new BasicNameValuePair("userpwd", pwd)); // 添加必须的参数
             request.setEntity(new UrlEncodedFormEntity(params, org.apache.http.protocol.HTTP.UTF_8)); // 设置参数的编码

             HttpResponse httpResponse = new DefaultHttpClient().execute(request); // 发送请求并获取反馈

             // 解析返回的内容
             if (httpResponse.getStatusLine().getStatusCode() != ) {
                 InputStream inputStream = httpResponse.getEntity().getContent();
                 in = new InputStreamReader(inputStream);
                 BufferedReader bufferedReader = new BufferedReader(in);

                 StringBuffer strBuffer = new StringBuffer();
                 String line = null;
                 while ((line = bufferedReader.readLine()) != null) {
                     strBuffer.append(line);
                 }
                 inputStream.close();
                 bufferedReader.close();
                 result = strBuffer.toString();
                 String errCode = "";
                 String strresult = "";
                 JSONObject root = new JSONObject(result);
                 errCode = root.getString("Code");

                 if (errCode.equals("")) {

                     strresult = root.getString("Result");
 /*
                     JSONArray resultArray = new JSONArray(strresult);//解析result
                     JSONObject resultobj = resultArray.getJSONObject(0);
                      resultobj.getString("UserName");
                    resultobj.getString("UserPwd");
                    */

                     result = strresult;
                     return result;
                 } else {
                     return "-1";
                 }

             }

         } catch (IOException e) {
             e.printStackTrace();
             Log.d("debug", e.toString());
             return "";
         } catch (JSONException e) {
             e.printStackTrace();
             Log.d("debug", e.toString());

         } finally {

             if (in != null) {
                 try {
                     in.close();
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
             }
         }
         return result;
     }

3、读取访问WEB服务结果

try {
            //启动后台异步线程进行连接webService操作，并且根据返回结果在主线程中改变UI
            GetWebResultTask queryAddressTask = new GetWebResultTask();

            //启动后台任务
            queryAddressTask.execute(etname.getText().toString(), etpwd.getText().toString());

        } catch (Exception ex) {

        }

 public class GetWebResultTask extends AsyncTask<String, Integer, String> {
        @Override
        protected String doInBackground(String... params) {
            String GetResult = "";
            try {

                GetResult = WebByHttp.GetUsers(params[], params[]);

                DialogBase.showmessage(LogIn.this, "GetResult:" + GetResult, "doInBackground");
            } catch (Exception e) {
                e.printStackTrace();

            }
            //将结果返回给onPostExecute方法
            return GetResult;

        }

        @Override
        //此方法可以在主线程改变UI
        protected void onPostExecute(String result) {
            // 将WebService返回的结果显示在TextView中
            tvresult.setText(result);
            try {
                if (result=="") {
                    DialogBase.showmessage(LogIn.this, "网络连接有误，请检查网络地址配置信息！", "确定");
                    return;
                }
                if (result=="-1") {

                    DialogBase.showmessage(LogIn.this, "账号或密码有误！", "确定");
                } else {
                    Intent itent = new Intent(LogIn.this, MainActivity.class);
                    startActivity(itent);
                }

            } catch (Exception e) {
                e.printStackTrace();

            }

        }
    }