LocationTracker.java

package org.greengin.sciencetoolkit.common.logic.location;

import java.util.List;

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

import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;

public class LocationTracker implements LocationListener {

	Context applicationContext;
	LocationManager locationManager;
	List<String> providers;
	
	protected Location best;

	public LocationTracker(Context applicationContext) {
		this.applicationContext = applicationContext;
		this.locationManager = (LocationManager) this.applicationContext
				.getSystemService(Context.LOCATION_SERVICE);
		this.providers = this.locationManager.getAllProviders();
	}

	protected void setListening(boolean listening) {
		if (listening) {
			for (String provider : providers) {
				this.updateLocation(locationManager
						.getLastKnownLocation(provider));
				locationManager.requestLocationUpdates(provider, 1000, 0, this);
			}
		} else {
			locationManager.removeUpdates(this);
		}

	}

	private void updateLocation(Location location) {
		if (location != null) {
			this.best = location;
		}
	}

	public String locationString() {
		if (best != null) {
			try {
				JSONObject obj = new JSONObject();
				obj.put("lat", best.getLatitude());
				obj.put("lon", best.getLongitude());
				obj.put("alt", best.getAltitude());
				obj.put("acc", best.getAccuracy());
				return obj.toString();
			} catch (JSONException e) {
				e.printStackTrace();
			}
		}
		return "";
	}

	@Override
	public void onLocationChanged(Location location) {
		this.updateLocation(location);
	}

	@Override
	public void onProviderDisabled(String provider) {
	}

	@Override
	public void onProviderEnabled(String provider) {
	}

	@Override
	public void onStatusChanged(String provider, int status, Bundle extras) {
	}

}