How to populate Android list view from json

In this post I'm going to illustrate how to add items to Android list view from data in json format.
I will use following json format to populate the list view

{"employee":[{"emp_name":"employee1","emp_no":"101700"}]}

First create an Android project, go to res>>layout directory and open activity_main.xml in Graphical  Layout view and delete the default TextView

Next from the Palette open "Composite" and drag a ListView to the layout file.

Here is the code of activity_main.xml file

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    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="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true" >
    </ListView>

</RelativeLayout>

Following is the sample code for MainActivity which  populates Android list view from a json array.

package com.axel.jsonlistview;
package com.axel.jsonlistview;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

public class MainActivity extends Activity {
 //json string
 private String jsonString = "{\"employee\":[{\"emp_name\":\"employee1\",\"emp_no\":\"101700\"},{\"emp_name\":\"employee2\",\"emp_no\":\"101701\"},{\"emp_name\":\"employee3\",\"emp_no\":\"101702\"},"+
        "{\"emp_name\":\"employee4\",\"emp_no\":\"101703\"},{\"emp_name\":\"employee5\",\"emp_no\":\"101704\"},{\"emp_name\":\"employee6\",\"emp_no\":\"101705\"},"+
        "{\"emp_name\":\"employee7\",\"emp_no\":\"101706\"},{\"emp_name\":\"employee8\",\"emp_no\":\"101707\"},{\"emp_name\":\"employee9\",\"emp_no\":\"101708\"},"+
        "{\"emp_name\":\"employee10\",\"emp_no\":\"101709\"},{\"emp_name\":\"employee11\",\"emp_no\":\"101710\"},{\"emp_name\":\"employee12\",\"emp_no\":\"101711\"},"+
        "{\"emp_name\":\"employee13\",\"emp_no\":\"101712\"},{\"emp_name\":\"employee14\",\"emp_no\":\"101713\"},{\"emp_name\":\"employee15\",\"emp_no\":\"101712\"}]}";
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  initList();
  ListView listView = (ListView) findViewById(R.id.listView1);
  SimpleAdapter simpleAdapter = new SimpleAdapter(this, employeeList, android.R.layout.simple_list_item_1, new String[] {"employees"}, new int[] {android.R.id.text1});
  listView.setAdapter(simpleAdapter);
 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  // Inflate the menu; this adds items to the action bar if it is present.
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }
 
 List<Map<String,String>> employeeList = new ArrayList<Map<String,String>>();
 private void initList(){
  
  try{
   JSONObject jsonResponse = new JSONObject(jsonString);
   JSONArray jsonMainNode = jsonResponse.optJSONArray("employee");
  
  for(int i = 0; i<jsonMainNode.length();i++){
   JSONObject jsonChildNode = jsonMainNode.getJSONObject(i);
   String name = jsonChildNode.optString("emp_name");
   String number = jsonChildNode.optString("emp_no");
   String outPut = name + "-" +number;
   employeeList.add(createEmployee("employees", outPut));
  }
 }
  catch(JSONException e){
   Toast.makeText(getApplicationContext(), "Error"+e.toString(), Toast.LENGTH_SHORT).show();
  }
 }
 
 private HashMap<String, String>createEmployee(String name,String number){
  HashMap<String, String> employeeNameNo = new HashMap<String, String>();
  employeeNameNo.put(name, number);
  return employeeNameNo;
 }

}

Demo of the application:

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