我希望请求作为JSON数组而不是来自我的Android应用程序的http URL用于Web服务

Question

你好我是android的新手，我有一个web服务接受数据作为json数组，我正在检查Android应用程序。我从网站上获得了一些代码，这些代码符合我的需求，但我并不理解这段代码发布的是json数组。我搜索了解决方案，我发现我应该使用  JSONObject jsonObject = new JSONObject();但我不明白我应该在哪里以及如何使用它。我也必须使用  httpPost.setHeader("Content-type", "application/json");因为我的Web服务提供响应，因为XML或JSON取决于内容类型。

package com.example.roshan.vidyut_1;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import com.loopj.android.http.RequestParams;

import org.json.JSONException;
import org.json.JSONObject;

/**
 * 
 * Login Activity Class 
 *
 */
public class LoginActivity extends Activity {
    // Progress Dialog Object
    ProgressDialog prgDialog;
    // Error Msg TextView Object
    TextView errorMsg;
    // Email Edit View Object
    EditText emailET;
    // Passwprd Edit View Object
    EditText pwdET;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login);
        // Find Error Msg Text View control by ID
        errorMsg = (TextView)findViewById(R.id.login_error);
        // Find Email Edit View control by ID
        emailET = (EditText)findViewById(R.id.loginEmail);
        // Find Password Edit View control by ID
        pwdET = (EditText)findViewById(R.id.loginPassword);
        // Instantiate Progress Dialog object
        prgDialog = new ProgressDialog(this);
        // Set Progress Dialog Text
        prgDialog.setMessage("Please wait...");
        // Set Cancelable as False
        prgDialog.setCancelable(false);
    }

    /**
     * Method gets triggered when Login button is clicked
     * 
     * @param view
     */
    public void loginUser(View view){
        // Get Email Edit View Value
        String email = emailET.getText().toString();
        // Get Password Edit View Value
        String password = pwdET.getText().toString();
        // Instantiate Http Request Param Object
        RequestParams params = new RequestParams();
        // When Email Edit View and Password Edit View have values other than Null
        if(Utility.isNotNull(email) && Utility.isNotNull(password)){
            // When Email entered is Valid

                // Put Http parameter username with value of Email Edit View control
                params.add("username", email);
                // Put Http parameter password with value of Password Edit Value control
                params.add("password", password);

                // Invoke RESTful Web Service with Http parameters
                invokeWS(params);
            }
            // When Email is invalid


        // When any of the Edit View control left blank
        else{
            Toast.makeText(getApplicationContext(), "Please fill the form, don't leave any field blank", Toast.LENGTH_LONG).show();
        }

    }

    /**
     * Method that performs RESTful webservice invocations
     *
     * @param params
     */
    public void invokeWS(RequestParams params){
        // Show Progress Dialog
         prgDialog.show();
         // Make RESTful webservice call using AsyncHttpClient object
         AsyncHttpClient client = new AsyncHttpClient();
         client.get("http://192.168.1.102:8080/vidyut-demo/login",params ,new AsyncHttpResponseHandler() {
             // When the response returned by REST has Http response code '200'
             @Override
             public void onSuccess(String response) {
                 // Hide Progress Dialog
                 prgDialog.hide();
                 try {
                         // JSON Object
                         JSONObject obj = new JSONObject(response);
                         // When the JSON response has status boolean value assigned with true
                         if(obj.getBoolean("status")){
                             Toast.makeText(getApplicationContext(), "You are successfully logged in!", Toast.LENGTH_LONG).show();
                             // Navigate to Home screen
                             navigatetoHomeActivity();
                         } 
                         // Else display error message
                         else{
                             errorMsg.setText(obj.getString("error_msg"));
                             Toast.makeText(getApplicationContext(), obj.getString("error_msg"), Toast.LENGTH_LONG).show();

                         }
                 } catch (JSONException e) {
                     // TODO Auto-generated catch block
                     Toast.makeText(getApplicationContext(), "Error Occured [Server's JSON response might be invalid]!", Toast.LENGTH_LONG).show();
                     e.printStackTrace();

                 }
             }
             // When the response returned by REST has Http response code other than '200'
             @Override
             public void onFailure(int statusCode, Throwable error,
                 String content) {
                 // Hide Progress Dialog 
                 prgDialog.hide();
                 // When Http response code is '404'
                 if(statusCode == 404){
                     Toast.makeText(getApplicationContext(), "Requested resource not found", Toast.LENGTH_LONG).show();
                 }
                 // When Http response code is '500'
                 else if(statusCode == 500){
                     Toast.makeText(getApplicationContext(), "Something went wrong at server end", Toast.LENGTH_LONG).show();
                 } 
                 // When Http response code other than 404, 500
                 else{
                     Toast.makeText(getApplicationContext(), "Unexpected Error occcured! [Most common Error: Device might not be connected to Internet or remote server is not up and running]", Toast.LENGTH_LONG).show();
                 }
             }
         });
    }

    /**
     * Method which navigates from Login Activity to Home Activity
     */
    public void navigatetoHomeActivity(){
        Intent homeIntent = new Intent(getApplicationContext(),HomeActivity.class);
        homeIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(homeIntent);
    }

    /**
     * Method gets triggered when Register button is clicked
     * 
     * @param view
     */
    public void navigatetoRegisterActivity(View view){
        Intent loginIntent = new Intent(getApplicationContext(),RegisterActivity.class);
        loginIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(loginIntent);
    }

}