How to deal with JSON in Java (Android Studio)

Question

I'm new to android and i'm developing an Android App, i want to get JSON data from a URL : URL

I have the following code:

import java.io.IOException;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
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.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.os.Bundle;
import android.app.Activity;
import android.widget.TextView;

public class SingleContactActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.article);

        String url = "http://ana.fm/api/article/256281468161349/";
        TextView title = (TextView) findViewById(R.id.single_article_title);
        TextView desc = (TextView) findViewById(R.id.single_article_desc);


        String str = "";
        HttpResponse response;
        HttpClient myClient = new DefaultHttpClient();
        HttpGet myConnection = new HttpGet(url);

        try {
            response = myClient.execute(myConnection);
            str = EntityUtils.toString(response.getEntity(), "UTF-8");

        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }


        try{
            JSONObject parent_obj = new JSONObject(str);
            JSONArray jArray= parent_obj.getJSONArray("article");
            JSONObject json = jArray.getJSONObject(0);


            title.setText(json.getString("title"));
            desc.setText(json.getString("description"));


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

    }


}

And this is article.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!-- Article Cover Photo -->
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/single_article_cover_photo"
        android:layout_gravity="center_horizontal" />

    <!-- Article Title -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/single_article_title"
        android:layout_gravity="center_horizontal"
        android:textColor="#acacac" />

    <!-- Article Description -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/single_article_desc"
        android:layout_gravity="center_horizontal" />


</LinearLayout>

And i have set the internet permission in AndroidManifest.xml:

<uses-permission android:name="android.permission.INTERNET" />

But when i run the emulator i get: null null

I can't find anything wrong in my code.

I got it working with this code :

import java.io.IOException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.os.AsyncTask;

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.widget.TextView;

import java.io.InputStream;


public class SingleContactActivity extends Activity {

    public static String myArticleUrl = "http://ana.fm/api/article/256281468161349/";
    TextView title;
    TextView desc;

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

        title = (TextView) findViewById(R.id.single_article_title);
        desc = (TextView) findViewById(R.id.single_article_desc);

        new LoadAllArticles().execute();

    }

    // LOADING THE ARTICLE CONTENTS IN THE BACKGROUND
    class LoadAllArticles extends AsyncTask<String, String, Void> {

        private ProgressDialog progressDialog = new ProgressDialog(SingleContactActivity.this);
        InputStream inputStream = null;
        String result = "";
        HttpResponse httpResponse;
        HttpEntity httpEntity;

        protected void onPreExecute() {
            progressDialog.setMessage("Downloading article...");
            progressDialog.show();
            progressDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
                public void onCancel(DialogInterface arg0) {
                    LoadAllArticles.this.cancel(true);
                }
            });
        }

        @Override
        protected Void doInBackground(String... params) {

            String url_select = myArticleUrl;

            // Set up HTTP Get
            HttpClient httpClient = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(url_select);

            try {


                httpResponse = httpClient.execute(httpGet);
                result = EntityUtils.toString(httpResponse.getEntity(), "UTF-8");

            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        protected void onPostExecute(Void v) {
            //parse JSON data
            try {

                JSONObject parent_obj = new JSONObject(result);
                JSONArray jArray= parent_obj.getJSONArray("article");
                JSONObject json = jArray.getJSONObject(0);

                title.setText(json.getString("title"));
                desc.setText(json.getString("description"));
                this.progressDialog.dismiss();
            } catch (JSONException e) {
                Log.e("JSONException", "Error: " + e.toString());
            } // catch (JSONException e)
        }
    }
}

But now i need to deal with the HTML tags, anybody know how i can handle HTML tags in JSON ?

Answer 1

EDIT: Ok, I finally managed to get to my working PC so I corrected all the errors, this is now working:

import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.widget.TextView;
import java.io.InputStream;
import java.util.ArrayList;

public class SingleContactActivity extends Activity {
    String myArticleUrl = "http://ana.fm/api/article/256281468161349/";
    TextView txtTitle;
    TextView txtDesc;
    JSONParser jParser = new JSONParser();
    JSONArray articles = null;

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

        txtTitle = (TextView) findViewById(R.id.single_article_title);
        txtDesc = (TextView) findViewById(R.id.single_article_desc);

        new LoadAllArticles().execute();
    }

    // LOADING ALL ARTICLES IN THE BACKGROUND
    class LoadAllArticles extends AsyncTask<String, String, String> {

        private ProgressDialog progressDialog = new ProgressDialog(SingleContactActivity.this);
        InputStream inputStream = null;
        String result = "";
        String title = "";
        String description = "";

        protected void onPreExecute() {
            progressDialog.setMessage("Downloading articles...");
            progressDialog.show();
            progressDialog.setOnCancelListener(new     DialogInterface.OnCancelListener() {
                public void onCancel(DialogInterface arg0) {
                    LoadAllArticles.this.cancel(true);
                }
            });
        }

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

        String url_select = myArticleUrl;

        ArrayList<NameValuePair> param = new ArrayList<NameValuePair>();

        try {
            JSONObject json = jParser.makeHttpRequest(url_select,
                    "GET", param);  // Change "GET" to "POST" if you want the POST method

            articles = json.getJSONArray("article");

            JSONObject jsonObj = articles.getJSONObject(0);

            title = jsonObj.getString("title");
            description = jsonObj.getString("description");

        }
        catch (IllegalStateException e3) {
            Log.e("IllegalStateException", e3.toString());
            e3.printStackTrace();
        }
        catch (JSONException e5) {
            Log.e("JSONException", e5.toString());
            e5.printStackTrace();
        }

        return null;
        }

        @Override
        protected void onPostExecute(String s) {
            try {
                String newTitle = Html.fromHtml(title).toString();
                txtTitle.setText(newTitle);
                String newDesc = Html.fromHtml(description).toString();
                txtDesc.setText(newDesc);
                progressDialog.dismiss();
            } catch (Exception e) {
                Log.e("JSONException", "Error: " + e.toString());
            }
        }

    }
}

And you need the JSONParser class:

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

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
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.client.utils.URLEncodedUtils;
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() {

    }

    // function get json from url
    // by making HTTP POST or GET mehtod
    public JSONObject makeHttpRequest(String url, String method,
                                      List<NameValuePair> params) {

        // Making HTTP request
        try {

            // check for request method
            if(method == "POST"){
                // request method is POST
                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            }else if(method == "GET"){
                // request method is GET
                DefaultHttpClient httpClient = new DefaultHttpClient();
                String paramString = URLEncodedUtils.format(params, "utf-8");
                url += "?" + paramString;
                HttpGet httpGet = new HttpGet(url);

                HttpResponse httpResponse = httpClient.execute(httpGet);
                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) {
                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;

    }
} 

Try this, it is working for me, I can see a bunch of arabic text...

Answer 2

Instead of anal parsing, you can use GSON . You will get your publications are java objects.