Get Time Zone of location, from web service of www.geonames.org

The GeoNames geographical database covers all countries and contains over eight million placenames that are available for download free of charge.

Using GeoNames WebServices, we can get time zone of any location. For example, the query:
http://api.geonames.org/timezoneJSON?formatted=true&lat=40.75649&lng=-73.98626&username=demo

return the time zone of the location of lat:40.75649 lng:-73.98626 (Nex York).

{

 "time": "2011-08-10 10:07",

 "countryName": "United States",

 "sunset": "2011-08-10 20:01",

 "rawOffset": -5,

 "dstOffset": -4,

 "countryCode": "US",

 "gmtOffset": -5,

 "lng": -73.98626,

 "sunrise": "2011-08-10 06:00",

 "timezoneId": "America/New_York",

 "lat": 40.75649

}

Please note that the parameter 'username' needs to be passed with each request. The username for your application can be registered here.

We can modify the exercise of "Parse JSON returned from Flickr Services" to parse the result to get the time zone.

package com.exercise.AndroidTimeZone;



import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.Reader;



import org.apache.http.HttpEntity;

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.json.JSONException;

import org.json.JSONObject;



import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;



public class AndroidTimeZoneActivity extends Activity {

	

	TextView textTimeZone;

	EditText inputLat, inputLon;

	Button buttonGetTimeZone;

	

	final static String DEFAULT_LAT = "40.75649";

	final static String DEFAULT_LON = "-73.98626";



   /** Called when the activity is first created. */

   @Override

   public void onCreate(Bundle savedInstanceState) {

       super.onCreate(savedInstanceState);

       setContentView(R.layout.main);

      

       textTimeZone = (TextView)findViewById(R.id.timezone);

       inputLat = (EditText)findViewById(R.id.lat);

       inputLat.setText(DEFAULT_LAT);

       inputLon = (EditText)findViewById(R.id.lon);

       inputLon.setText(DEFAULT_LON);

       buttonGetTimeZone = (Button)findViewById(R.id.getTimeZone);

       buttonGetTimeZone.setOnClickListener(buttonGetTimeZoneOnClickistener);

      

   }

  

   Button.OnClickListener buttonGetTimeZoneOnClickistener

   = new Button.OnClickListener(){



		@Override

		public void onClick(View v) {

			// TODO Auto-generated method stub

			

			String lat = inputLat.getText().toString();

			String lon = inputLon.getText().toString();

			

			String rqsurl = "http://api.geonames.org/timezoneJSON?formatted=true"

					+ "&lat=" + lat

					+ "&lng=" + lon

					+ "&username=demo";

			

			String jsonResult = QueryGeonames(rqsurl);

			String parsedResult = ParseJSON(jsonResult);

			textTimeZone.setText(parsedResult);

		}};

		

		private String QueryGeonames(String q){

			

			String qResult = null;

			HttpClient httpClient = new DefaultHttpClient();

			HttpGet httpGet = new HttpGet(q);

			

	        try {

	        	HttpEntity httpEntity = httpClient.execute(httpGet).getEntity();

	        	

	        	if (httpEntity != null){

	        		InputStream inputStream = httpEntity.getContent();

	        	    Reader in = new InputStreamReader(inputStream);

	        	    BufferedReader bufferedreader = new BufferedReader(in);

	        	    StringBuilder stringBuilder = new StringBuilder();

	        	   

	        	    String stringReadLine = null;

	        	   

	        	    while ((stringReadLine = bufferedreader.readLine()) != null) {

	        	    	stringBuilder.append(stringReadLine + "\n");	

	        	    }

	        	   

	        	    qResult = stringBuilder.toString();   

	        	}	

	        } catch (ClientProtocolException e) {

	        	// TODO Auto-generated catch block

	        	e.printStackTrace();	

	        } catch (IOException e) {

	        	// TODO Auto-generated catch block

	        	e.printStackTrace();	

	        }

			

			return qResult;

		}

		    

		

		private String ParseJSON(String json){

			

			String jResult = null;

			

			try {

				JSONObject JsonObject = new JSONObject(json);

				

				jResult = "\n"

						+ "lat: " + JsonObject.getString("lat") + "\n"

						+ "lng: " + JsonObject.getString("lng") + "\n"

						+ "countryName: " + JsonObject.getString("countryName") + "\n"

						+ "countryCode: " + JsonObject.getString("countryCode") + "\n"

						+ "timezoneId: " + JsonObject.getString("timezoneId") + "\n"

						+ "rawOffset: " + JsonObject.getString("rawOffset") + "\n"

						+ "dstOffset: " + JsonObject.getString("dstOffset") + "\n"

						+ "gmtOffset: " + JsonObject.getString("gmtOffset") + "\n";

				

			} catch (JSONException e) {

				// TODO Auto-generated catch block

				e.printStackTrace();	

			}

			

			return jResult;	

		}		       

}

Layout, main.xml

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

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

   android:orientation="vertical"

   android:layout_width="fill_parent"

   android:layout_height="fill_parent"

   >

<TextView 

   android:layout_width="fill_parent"

   android:layout_height="wrap_content"

   android:text="@string/hello"

   />

<TextView

   android:layout_width="fill_parent"

   android:layout_height="wrap_content"

   android:text="lat"

   />

<EditText

   android:id="@+id/lat"

   android:layout_width="fill_parent"

   android:layout_height="wrap_content"

   />

<TextView

   android:layout_width="fill_parent"

   android:layout_height="wrap_content"

   android:text="lon"

   />

<EditText

   android:id="@+id/lon"

   android:layout_width="fill_parent"

   android:layout_height="wrap_content"

   />

<Button

   android:id="@+id/getTimeZone"

   android:layout_width="fill_parent"

   android:layout_height="wrap_content"

   android:text="Get Time Zone from geonames.org"

   />

<TextView 

   android:id="@+id/timezone"

   android:layout_width="fill_parent"

   android:layout_height="wrap_content"

   />

</LinearLayout>

Please remember you you have to modify AndroidManifest.xml to grant permission of "android.permission.INTERNET".


Download the files.