JSON Tutorial II

In this tutorial, I will show you some example of retrieving data from webservice that return a json format. See output below.

Create a separate class and named it JSONParser.java. See code below!

package com.example.retrieveapi;

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;

}
}

Next is in your MainActivity.java. See code below!.

package com.example.retrieveapi;

import java.util.ArrayList;

import java.util.HashMap;

import org.json.JSONArray;

import org.json.JSONObject;

import android.annotation.SuppressLint;

import android.app.AlertDialog;

import android.app.ListActivity;

import android.app.ProgressDialog;

import android.content.DialogInterface;

import android.os.Bundle;

import android.os.StrictMode;

import android.view.View;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.ListAdapter;

import android.widget.ListView;

import android.widget.RelativeLayout;

import android.widget.SimpleAdapter;

import android.widget.TextView;

public class MainActivity extends ListActivity {

// url to make request

private static String url = "http://api.androidhive.info/contacts/";

JSONArray contacts = null;

// JSON Node names

private static final String TAG_CONTACTS = "contacts";

private static final String TAG_ID = "id";

private static final String TAG_NAME = "name";

private static final String TAG_EMAIL = "email";

private static final String TAG_ADDRESS = "address";

private static final String TAG_GENDER = "gender";

private static final String TAG_PHONE = "phone";

private static final String TAG_PHONE_MOBILE = "mobile";

private static final String TAG_PHONE_HOME = "home";

private static final String TAG_PHONE_OFFICE = "office";

private Runnable search, returnRes;

private ProgressDialog m_ProgressDialog = null;

ArrayList<HashMap<String, String>> list;

@SuppressLint("NewApi")

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();

   StrictMode.setThreadPolicy(policy);

   

search = new Runnable() {

@Override

public void run() {

try {

Thread.sleep(2000);

runOnUiThread(returnRes);

}catch (Exception ex){

        ex.printStackTrace();

}

}

};

Thread thread =  new Thread(null, search, "MagentoBackground");

thread.start();

m_ProgressDialog = ProgressDialog.show(this,"Please wait...", "Connecting...", true);

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

   returnRes = new Runnable() {

@Override

public void run() {

       

// Creating JSON Parser instance

JSONParser jParser = new JSONParser();

// getting JSON string from URL

JSONObject json = jParser.getJSONFromUrl(url);

try{

contacts = json.getJSONArray(TAG_CONTACTS);

//Toast.makeText(getApplicationContext(), Integer.toString(contacts.length()), Toast.LENGTH_SHORT).show();

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

JSONObject c = contacts.getJSONObject(i);

String id = c.getString(TAG_ID);

String name = c.getString(TAG_NAME);

String email = c.getString(TAG_EMAIL);

String address = c.getString(TAG_ADDRESS);

String gender = c.getString(TAG_GENDER);

JSONObject phone = c.getJSONObject(TAG_PHONE);

String mobile = phone.getString(TAG_PHONE_MOBILE);

String home = phone.getString(TAG_PHONE_HOME);

String office = phone.getString(TAG_PHONE_OFFICE);

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

map.put("id", id);

map.put("name", name);

map.put("email", email);

map.put("address", address);

map.put("gender", gender);

map.put("mobile", mobile);

map.put("home", home);

map.put("office", office);

list.add(map);

}

}catch(Exception e){

e.printStackTrace();

}

             

             

       

ListAdapter adapter = new SimpleAdapter(getApplicationContext(), list, R.layout.list_item,

new String[] {TAG_ID, TAG_NAME, TAG_ADDRESS, TAG_EMAIL, TAG_GENDER, TAG_PHONE_HOME, TAG_PHONE_MOBILE, TAG_PHONE_OFFICE },

new int[] {R.id.tv_id, R.id.tv_name, R.id.tv_address, R.id.tv_email, R.id.tv_gender, R.id.tv_hide_home, R.id.tv_hide_mobile, R.id.tv_hide_office}); 

         

ListView lv = getListView();

lv.setAdapter(adapter);

         

lv.setOnItemClickListener(new OnItemClickListener() {

@Override

public void onItemClick(AdapterView<?> arg0, View view, int arg2,

long arg3) {

// TODO Auto-generated method stub

String tv_num1 = ((TextView) view.findViewById(R.id.tv_hide_mobile)).getText().toString();

String tv_num2 = ((TextView) view.findViewById(R.id.tv_hide_home)).getText().toString();

String tv_num3 = ((TextView) view.findViewById(R.id.tv_hide_office)).getText().toString();

    AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();

    alertDialog.setTitle("Contact");

    alertDialog.setMessage("Mobile: "+tv_num1+"\n"+"Home: "+tv_num2+"\n"+"Office: "+tv_num3);

    alertDialog.setIcon(R.drawable.ic_launcher);

    alertDialog.setButton("OK", new DialogInterface.OnClickListener() {

               public void onClick(DialogInterface dialog, int which) {

               // Write your code here to execute after dialog closed

               dialog.dismiss();

               }

       });

 

       // Showing Alert Message

       alertDialog.show();

}

});

       

m_ProgressDialog.dismiss();

}

};

}

}

And I have 3 XML layout here. Just see code below!

activity_main.xml

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

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/rl_main"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >

   <ListView

        android:id="@android:id/list"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"/>

</RelativeLayout>

content.xml

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

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

    android:id="@+id/RelativeLayout1"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:padding="5dp"

    android:orientation="vertical" >

    <TextView

        android:id="@+id/tv_num1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_alignParentTop="true"

        android:text="Mobile" />

    <TextView

        android:id="@+id/tv_num2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_below="@+id/tv_num1"

        android:text="Home" />

    <TextView

        android:id="@+id/tv_num3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/tv_num2"

        android:layout_below="@+id/tv_num2"

        android:text="Office" />

</RelativeLayout>

list_item.xml

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

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

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:padding="5dp" >

    <TextView

        android:id="@+id/tv_id"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentRight="true"

        android:layout_alignParentTop="true"

        android:text="ID" />

    <TextView

        android:id="@+id/tv_name"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/tv_id"

        android:layout_alignBottom="@+id/tv_id"

        android:layout_alignParentLeft="true"

        android:text="NAME" />

    <TextView

        android:id="@+id/tv_address"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/tv_name"

        android:layout_below="@+id/tv_name"

        android:text="Address" />

    <TextView

        android:id="@+id/tv_email"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_below="@+id/tv_address"

        android:text="Email" />

    <TextView

        android:id="@+id/tv_gender"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/tv_email"

        android:layout_below="@+id/tv_email"

        android:text="Gender" />

    <TextView

        android:id="@+id/tv_hide_mobile"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/tv_gender"

        android:layout_alignBottom="@+id/tv_gender"

        android:layout_toRightOf="@+id/tv_address"

        android:visibility="gone"

        android:textSize="5sp"

        android:text="Mobile" />

    <TextView

        android:id="@+id/tv_hide_home"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/tv_hide_mobile"

        android:layout_alignBottom="@+id/tv_hide_mobile"

        android:layout_toRightOf="@+id/tv_hide_mobile"

        android:textSize="5sp"

        android:visibility="gone"

        android:text="Home" />

    <TextView

        android:id="@+id/tv_hide_office"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/tv_hide_home"

        android:layout_alignBottom="@+id/tv_hide_home"

        android:layout_toRightOf="@+id/tv_hide_home"

        android:textSize="5sp"

        android:visibility="gone"

        android:text="Office" />

</RelativeLayout>

And lastly in your AndroidManifest.xml. See code below!

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

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

    package="com.example.retrieveapi"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="17" />

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

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name="com.example.retrieveapi.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>

</manifest>

It is important to declare a user_permission from the internet. And ON your WIFI in running this application. That's it, hope this may help you. Happy coding.!