Android Json Parsing

Step 1 :

Make an android project.

Step 2 :

Paste the following code in MainActivity. java file.

import java.util.ArrayList;

import java.util.HashMap;

import learn2crack.listview.R;

import learn2crack.listview.library.JSONParser;

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;

import android.app.ProgressDialog;

import android.os.AsyncTask;

import android.os.Bundle;

import android.support.v7.app.ActionBarActivity;

import android.view.View;

import android.widget.AdapterView;

import android.widget.Button;

import android.widget.ListAdapter;

import android.widget.ListView;

import android.widget.SimpleAdapter;

import android.widget.TextView;

import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

       ListView list;

       TextView ver;

       TextView name;

       TextView api;

       Button Btngetdata;

       // ProgressBar pgbar;

       ArrayList<HashMap<String, String>> oslist = new ArrayList<HashMap<String, String>>();

       // URL to get JSON Array

       private static String url = "http://10.0.2.2/android/jsonos/";

       // JSON Node Names

       private static final String TAG_OS = "android";

       private static final String TAG_VER = "ver";

       private static final String TAG_NAME = "name";

       private static final String TAG_API = "api";

       JSONArray android = null;

       @Override

       protected void onCreate(Bundle savedInstanceState) {

              super.onCreate(savedInstanceState);

              setContentView(R.layout.activity_main);

              oslist = new ArrayList<HashMap<String, String>>();

              Btngetdata = (Button) findViewById(R.id.getdata);

              Btngetdata.setOnClickListener(new View.OnClickListener() {

                     @Override

                     public void onClick(View view) {

                           new JSONParse().execute();

                     }

              });

       }

       private class JSONParse extends AsyncTask<String, String, JSONObject> {

              private ProgressDialog pDialog;

              @Override

              protected void onPreExecute() {

                     super.onPreExecute();

                     ver = (TextView) findViewById(R.id.vers);

                     name = (TextView) findViewById(R.id.name);

                     api = (TextView) findViewById(R.id.api);

                     // pgbar = (ProgressBar) findViewById(R.id.progressBar1);

                     pDialog = new ProgressDialog(MainActivity.this);

                     pDialog.setMessage("Getting Data ...");

                     pDialog.setIndeterminate(false);

                     pDialog.setCancelable(true);

                     pDialog.show();

              }

              @Override

              protected JSONObject doInBackground(String... args) {

                     JSONParser jParser = new JSONParser();

                     // Getting JSON from URL

                     JSONObject json = jParser.getJSONFromUrl(url);

                     return json;

              }

              @Override

              protected void onPostExecute(JSONObject json) {

                     // pgbar.setVisibility(View.GONE);

                     pDialog.dismiss();

                     try {

                           // Getting JSON Array from URL

                           android = json.getJSONArray(TAG_OS);

                           for (int i = 0; i < android.length(); i++) {

                                  JSONObject c = android.getJSONObject(i);

                                  // Storing JSON item in a Variable

                                  String ver = c.getString(TAG_VER);

                                  String name = c.getString(TAG_NAME);

                                  String api = c.getString(TAG_API);

                                  // Adding value HashMap key => value

                                  HashMap<String, String> map = new HashMap<String, String>();

                                  map.put(TAG_VER, ver);

                                  map.put(TAG_NAME, name);

                                  map.put(TAG_API, api);

                                  oslist.add(map);

                                  list = (ListView) findViewById(R.id.list);

                                  ListAdapter adapter = new SimpleAdapter(MainActivity.this,

                                                oslist, R.layout.list_v, new String[] { TAG_VER,

                                                              TAG_NAME, TAG_API }, new int[] { R.id.vers,

                                                              R.id.name, R.id.api });

                                  list.setAdapter(adapter);

                                  list.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                                         @Override

                                         public void onItemClick(AdapterView<?> parent,

                                                       View view, int position, long id) {

                                                Toast.makeText(

                                                              MainActivity.this,

                                                              "You Clicked at "

                                                                           + oslist.get(+position).get("name"),

                                                              Toast.LENGTH_SHORT).show();

                                         }

                                  });

                           }

                     } catch (JSONException e) {

                           e.printStackTrace();

                     }

              }

       }

}

Step 3 :

Make another  package in src file.

Step 4 :

Make another Java class named “JSONParser” in your new package.

Step 5 :

Paste the following code in JSONParser.java file.

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) {

                           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;

       }

}

Step 6:

Paste the following code in activity_main.xml file.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent" >

    <ListView

        android:id="@+id/list"

        android:layout_width="match_parent"

        android:layout_height="435dp"

        android:layout_above="@+id/getdata" >

    </ListView>

    <Button

        android:id="@+id/getdata"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentBottom="true"

        android:layout_alignParentRight="true"

        android:text="Get Data" />

</RelativeLayout>

Step 7 :

Make another layout file in layout folder named “list_v.xml”.

Step 8 :

Paste the following code in list_v.xml file.

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

    <TextView

        android:id="@+id/vers"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />

    <TextView

        android:id="@+id/name"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />

    <TextView

        android:id="@+id/api"

        android:layout_width="match_parent"

        android:layout_height="wrap_content" />

</LinearLayout>

Step 9:

Paste the following code in AndroidMenifest.xml file.

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="learn2crack.listview"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="19" />

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name="learn2crack.listview.main.MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

    </application>

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

</manifest>

Note :

Json was in format.

{

"android": [

{

"ver": "1.5",

"name": "Cupcake",

"api": "API level 3"

},

{

"ver": "1.6",

"name": "Donut",

"api": "API level 4"

},

{

"ver": "2.0-2.1",

"name": "Eclair",

"api": "API level 5-7"

},

{

"ver": "2.2",

"name": "Froyo",

"api": "API level 8"

},

{

"ver": "2.3",

"name": "Gingerbread",

"api": "API level 9-10"

},

{

"ver": "3.0-3.2",

"name": "Honeycomb",

"api": "API level 11-13"

},

{

"ver": "4.0",

"name": "Ice Cream Sandwich",

"api": "API level 14-15"

},

{

"ver": "4.1-4.3",

"name": "JellyBean",

"api": "API level 16-18"

},

{

"ver": "4.4",

"name": "KitKat",

"api": "API level 19"

}

]

}