------为您的项目创建一个服务处理程序类--------
public class ServiceHandler {
static String response = null;
public final static int GET = 1;
public final static int POST = 2;
public ServiceHandler() {
}
/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * */
public String makeServiceCall(String url, int method) {
    return this.makeServiceCall(url, method, null);
}
/*
 * Making service call
 * @url - url to make request
 * @method - http request method
 * @params - http request params
 * */
public String makeServiceCall(String url, int method,
        List<NameValuePair> params) {
    try {
        // http client
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpEntity httpEntity = null;
        HttpResponse httpResponse = null;
        // Checking http request method type
        if (method == POST) {
            Log.e("in POST","in POST");
            HttpPost httpPost = new HttpPost(url);
            // adding post params
            if (params != null) {
                Log.e("in POST params","in POST params");
                httpPost.setEntity(new UrlEncodedFormEntity(params));
            }
            Log.e("url in post service",url);
            httpResponse = httpClient.execute(httpPost);
        } else if (method == GET) {
            // appending params to url
            Log.e("in GET","in GET");
            if (params != null) {
                Log.e("in GET params","in GET params");
                String paramString = URLEncodedUtils
                        .format(params, "utf-8");
                url += "?" + paramString;
            }
            Log.e("url in get service",url);
            HttpGet httpGet = new HttpGet(url);
            httpResponse = httpClient.execute(httpGet);
        }
        httpEntity = httpResponse.getEntity();
        response = EntityUtils.toString(httpEntity);
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return response;
}
public String makeServiceCallIMAGE(String url, int method,
        List<NameValuePair> params) {
    try {
        // http client
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpEntity httpEntity = null;
        HttpResponse httpResponse = null;
        // Checking http request method type
        if (method == POST) {
            HttpPost httpPost = new HttpPost(url);
            // adding post params
            if (params != null) {
                httpPost.setEntity(new UrlEncodedFormEntity(params));
            }
            httpResponse = httpClient.execute(httpPost);
        } else if (method == GET) {
            // appending params to url
            if (params != null) {
                String paramString = URLEncodedUtils
                        .format(params, "utf-8");
                url += "?" + paramString;
            }
            HttpGet httpGet = new HttpGet(url);
            httpResponse = httpClient.execute(httpGet);
        }
        httpEntity = httpResponse.getEntity();
        response = EntityUtils.toString(httpEntity);
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return response;
}
}
--------------用于登录的异步任务------
public class Login_Activity extends ActionBarActivity {
//Internet Service
NetworkConnection nw;
ProgressDialog prgDialog;
Boolean netConnection = false;
//
//Login API
String loginURL ="url";
//
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);
    nw = new NetworkConnection(getApplicationContext());
    prgDialog = new ProgressDialog(this);
    // Set Cancelable as False
    prgDialog.setCancelable(false);
    new LoginOperation().execute();
}
private class LoginOperation  extends AsyncTask<String, Void, Void> {
    String status, message;
    @Override
    protected void onPreExecute() {
        // Set Progress Dialog Text
        prgDialog.setMessage("Logging...");
        prgDialog.show();
    }
    @Override
    protected Void doInBackground(String... urls) {
        if(nw.isConnectingToInternet() == true)
        {
            try
            {
                List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
                nameValuePairs.add(new BasicNameValuePair("method", "ClientesLogin"));
                nameValuePairs.add(new BasicNameValuePair("Email", str_Email));
                nameValuePairs.add(new BasicNameValuePair("Senha", str_Password));
                ServiceHandler sh  = new ServiceHandler();
                String response = sh.makeServiceCall(loginURL, ServiceHandler.GET,
                        nameValuePairs);
                Log.e("response", response);
                JSONObject js = new JSONObject(response);
                status = js.getString("status");
                Log.e("status",status);
                if(status.contains("Fail"))
                {
                    message = js.getString("message");
                }
                /*else
                {
                    JSONObject jslogin=js.getJSONObject("user_list");
                    for (int i = 0; i < jslogin.length(); i++) {
                    }
                }*/
            }catch(Exception ex){
            }
            netConnection = true;
        }else
        {
            netConnection = false;
        }
        return null;
    }
    @Override
    protected void onPostExecute(Void result) {
        prgDialog.dismiss();
        if(netConnection == false)
        {
            Toast toast = Toast.makeText(getApplicationContext(),"Internet is not available. Please turn on and try again.", Toast.LENGTH_LONG);
            toast.setGravity(Gravity.CENTER, 0, 0);
            toast.show();
        }
        else
        {
            if(status.contains("Success"))
            {
                Toast toast = Toast.makeText(getApplicationContext(), "Login Successful", Toast.LENGTH_SHORT);
                toast.setGravity(Gravity.CENTER, 0, 0);
                toast.show();
                Intent i=new Intent(Login_Activity.this,home_page_activity.class);
                startActivity(i);
            }
            else{
                Toast toast = Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT);
                toast.setGravity(Gravity.CENTER, 0, 0);
                toast.show();
            }
        }
        super.onPostExecute(result);
    }
}
}
---------------网络连接类---------
public class NetworkConnection {
Context context;
public NetworkConnection(Context context){
    this.context = context;
}
public boolean isConnectingToInternet(){
    ConnectivityManager connectivity = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
      if (connectivity != null) 
      {
          NetworkInfo[] info = connectivity.getAllNetworkInfo();
          if (info != null) 
              for (int i = 0; i < info.length; i++) 
                  if (info[i].getState() == NetworkInfo.State.CONNECTED)
                  {
                      return true;
                  }
      }
      return false;
}
}
JSONArray main1 = js.getJSONArray("Test 1");
  for (int i = 0; i < main1.length(); i++) {
    JSONObject jsonObject = main1.getJSONObject(i);