it doesn't change the longitude & latitude

[sameera liyanage]

This is the my class

package com.visini.android;

import java.util.List;

import android.app.Activity;
import android.location.Address;
import android.location.Criteria;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.TextView;

	
	
public class LocationActivity extends Activity implements LocationListener {
	
	private LocationManager locationManager;
	private String locationdetails;
	
    /** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
	    super.onCreate(savedInstanceState);
	    setContentView(R.layout.main);
	    
	    TextView locationdetailstextview = (TextView)findViewById(R.id.locationDetailstextView);
	    
	    locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
	    
	    //Get the best provider  for the criteria
	    
	    Criteria criteria = new Criteria();
	    criteria.setPowerRequirement(Criteria.POWER_LOW);
	    criteria.setAccuracy(Criteria.ACCURACY_COARSE);
	    
	    String bestprovider = locationManager.getBestProvider(criteria,false);
	    
	    Location lastknownlocation = locationManager.getLastKnownLocation(bestprovider);
	    
	    //Location lastknownlocation = locationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
	
	    if (lastknownlocation != null){
	    	  	locationdetails = "Last Know Location:----- Latitude: "+lastknownlocation.getLatitude() +"Longitude :"+lastknownlocation.getLongitude();
	    locationdetailstextview.setText(locationdetails);
	    }
	    
	    locationManager.requestLocationUpdates(bestprovider,5000, 0.2f, this);
	    
	   // locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,5000, 0.2f, this);
	    
	}

	@Override
	public void onLocationChanged(Location location) {
		
		try{
		// TODO Auto-generated method stub
	    TextView locationdetailstextview = (TextView)findViewById(R.id.locationDetailstextView);
	 	locationdetails += "\n Current Location:----- Latitude: "+location.getLatitude() +"Longitude :"+location.getLongitude();
	    locationdetailstextview.setText(locationdetails);
	    
	    //get the address using google map
	    Geocoder geocoder = new Geocoder(this);
	    List<Address> addresses = geocoder.getFromLocation(location.getLatitude(),location.getLongitude(),1);
	    
	    
	    for (Address address: addresses){
	    	
	    	locationdetails += "Address is "+address.getAddressLine(0)+" ,"+address.getCountryName();
	    	}
		}
		catch(Exception e){
			System.out.println(e.toString());
		}
	}

	@Override
	public void onProviderDisabled(String arg0) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void onProviderEnabled(String arg0) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
		// TODO Auto-generated method stub
		
	}
}

this is working fine .it shows the longitude & latitude.
1)But when i move the phone it doen't change the values.
2)Also it doen't show me the current address or country /