Parse JSON Data In Android

Introduction

 

JSON stands for JavaScript Object Notation. JSON is a light weight data interchange format in a text format so it can be easily parsed and read by machines and humans.

 

Parsing JSON data is important in Android. Create a new project on Android by using the following steps,

 

Step 1

 

 

 

Step 2

 

 

Step 3

 

 

Step 4

 

 

Step 5

 

 

JSON uses the following two types of different structures,

1. Collection of name/value pair
2. Array

Example of collection of name/value pair: The { (curly brace) represents the JSON object.

{"Employee" :{

   "id":"1",
   "name":"David",

   "address":"Delhi",

   "zip":"110002"}

}

Example of collection of array: The [ (square bracket ) represents the JSON array.

{
    "Employee": [
    {
        "id": "1",
        "name": "David",
        "address": "Delhi",
        "zip": "110002"
    },
    {
        "id": "2",
        "name": "John",
        "address": "Mumbai",
        "zip": "400001"
    },
    {
        "id": "3",
        "name": "Mathew",
        "address": "Delhi",
        "zip": "110003"
    },
    {
        "id": "4",
        "name": "Mary",
        "address": "Delhi",
        "zip": "110010"
    }]
}

Complete Java class to parse JSON data.

{
    "Employee": [
    {
        "id": "1",
        "name": "David",
        "address": "Delhi",
        "zip": "110002"
    },
    {
        "id": "2",
        "name": "John",
        "address": "Mumbai",
        "zip": "400001"
    },
    {
        "id": "3",
        "name": "Mathew",
        "address": "Delhi",
        "zip": "110003"
    },
    {
        "id": "4",
        "name": "Mary",
        "address": "Delhi",
        "zip": "110010"
    }]
}
package com.test.ppandey.jsonparse;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class MainActivity extends ActionBarActivity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TextView output = (TextView) findViewById(R.id.textView1);
        String strJson = "{\"Employee\" :[ {" + " \"id\":\"1\",\n" + "\"name\":\"David\",\n" + "\"address\":\"Delhi\", \n" + "\"zip\":\"110002\"}, {\n" + "\"id\":\"2\",\n" + "\"name\":\"John\",\n" + "\"address\":\"Mumbai\",\n" + "\"zip\":\"400001\"}, {\n" + "\"id\":\"3\",\n" + "\"name\":\"Mathew\",\n" + "\"address\":\"Delhi\",\n" + "\"zip\":\"110003\"}, {\n" + "\"id\":\"4\",\n" + "\"name\":\"Mary\",\n" + "\"address\":\"Delhi\",\n" + "\"zip\":\"110010\"} \n" + "]}";
        String data = "";
        try
        {
            JSONObject jsonRootObject = new JSONObject(strJson);
            //Instance of JSONArray that contains JSONObjects
            JSONArray jsonArray = jsonRootObject.optJSONArray("Employee");
            //Iterate the jsonArray and print the information of the JSONObjects
            for (int i = 0; i < jsonArray.length(); i++)
            {
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                int id = Integer.parseInt(jsonObject.optString("id").toString());
                String name = jsonObject.optString("name").toString();
                String address = jsonObject.optString("address").toString();
                String zip = jsonObject.optString("zip").toString();
                data += "Employee " + i + " : \n id= " + id + " \n Name= " + name + " \n Address= " + address + " \n zip=" + zip + "\n ";
            }
            output.setText(data);
        }
        catch (JSONException e)
        {
            e.printStackTrace();
        }
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings)
        {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

In the above code, we created string containing JSON data and object of class JSONObject.

JSONObject jsonRootObject = new JSONObject(strJson);

And pass string containing JSON data to it.

 

The second step is to parse the JSON.

JSONArray jsonArray = jsonRootObject.optJSONArray("Employee");
int id = Integer.parseInt(jsonObject.optString("id").toString());
String name = jsonObject.optString("name").toString();
String address = jsonObject.optString("address").toString();
String zip = jsonObject.optString("zip").toString();

Run the application and we get the JSON data as in the following.