Android Program to Demonstrate Connection to an Internet Resource

Here is source code of the Program to Demonstrate Connection to an Internet Resource in Android using Java. The program is successfully compiled and run on a Windows system using Eclipse Ide. The program output is also shown below.

In this program we initiate a HTTPS connection and using this connection we get a json object which we print on the screen.

Main Activity

package com.example.json_app;
 
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
 
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;
 
public class MainActivity extends Activity {
 
    // URL to get JSON Array
    private static String url = "http://evaluate.rome2rio.com/api/1.2/json/Search?key=fWAL2WvM&oName=Dwarka+Delhi&dName=Hauz+Khas+Delhi";
 
    JSONObject json = null;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        // Creating new JSON Parser
        final JSONParser jParser = new JSONParser();
 
        // Getting JSON from URL
        final TextView text = (TextView) findViewById(R.id.text);
 
          Thread thread = new Thread(new Runnable() {
 
          @Override public void run() { // TODO Auto-generated method stub json
              jParser.getJSONFromUrl(url);
 
          } }); thread.start();
    }
 
}

Json Parser

package com.example.json_app;
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
 
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
 
import android.util.Log;
 
public class JSONParser {
 
    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";
 
    // constructor
    public JSONParser() {
 
    }
 
    public JSONObject getJSONFromUrl(String url) {
 
        // Making HTTP request
        try {
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
 
            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
 
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
 
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                Log.i("Tag",line);
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }
 
        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }
 
        // return JSON String
        return jObj;
 
    }
}