Terrapins Sky: [Android] Get and parse Json file from URL, available for v23 sdk

Thursday, October 1, 2015

[Android] Get and parse Json file from URL, available for v23 sdk

I found a nice example from codeofaninja.com to get and parse json from URL in android:

Simple Android JSON Parser Example Code with URL and Logcat Output

However, Some of the syntax do not support ApacheHttp Client anymore in v23 sdk so that example from codeofaninja doesn't work anymore.

And here i would like to share the code amended from example, which is referenced from the android official site:

JsonParser.java :

package com.example.app;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URL;

import org.json.JSONObject;
import org.json.JSONException;
import java.io.IOException;

import java.net.HttpURLConnection;
import android.util.Log;

public class JsonParser {
    final String TAG = "JsonParser.java";
    static InputStream inputStream = null;
    static JSONObject jObj = null;
    static String json = "";

    public JSONObject getJSONFromUrl(String urlSource) {
        //make HTTP request
        try {
            URL url = new URL(urlSource);
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setDoOutput(true);
            urlConnection.setChunkedStreamingMode(0);
            inputStream = new BufferedInputStream(urlConnection.getInputStream());
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        //Read JSON data from inputStream
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            inputStream.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e(TAG, "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e(TAG, "Error parsing data " + e.toString());
        }

        return jObj;// return JSON String
    }
}

And the MainAcitivity.java

package com.example.app;

import android.app.Activity;

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

import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;

import com.example.app.JsonParser;

public class MainActivity extends Activity {

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

        // we will using AsyncTask during parsing
        new AsyncTaskParseJson().execute();
    }

    // you can make this class as another java file so it will be separated from your main activity.
    public class AsyncTaskParseJson extends AsyncTask<String, String, String> {

        final String TAG = "AsyncTaskParseJson.java";

        // set your json string url here
        String yourJsonStringUrl = "http://demo.codeofaninja.com/tutorials/json-example-with-php/index.php";

        // contacts JSONArray
        JSONArray dataJsonArr = null;

        @Override
        protected void onPreExecute() {}

        @Override
        protected String doInBackground(String... arg0) {

            try {

                // instantiate our json parser
                JsonParser jParser = new JsonParser();

                // get json string from url
                JSONObject json = jParser.getJSONFromUrl(yourJsonStringUrl);

                // get the array of users
                dataJsonArr = json.getJSONArray("Users");

                // loop through all users
                for (int i = 0; i < dataJsonArr.length(); i++) {

                    JSONObject c = dataJsonArr.getJSONObject(i);

                    // Storing each json item in variable
                    String firstname = c.getString("firstname");
                    String lastname = c.getString("lastname");
                    String username = c.getString("username");

                    // show the values in our logcat
                    Log.e(TAG, "firstname: " + firstname
                            + ", lastname: " + lastname
                            + ", username: " + username);

                }

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

            return null;
        }

        @Override
        protected void onPostExecute(String strFromDoInBg) {}
    }
}