Geolocation.java

package com.example.geolocation;

import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.location.LocationProvider;
import android.os.Bundle;

import org.alfonz.utility.Logcat;

import java.lang.ref.WeakReference;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;


public class Geolocation implements LocationListener
{
	private static final int LOCATION_AGE = 60000 * 30; // milliseconds
	private static final int LOCATION_TIMEOUT = 30000; // milliseconds

	private WeakReference<GeolocationListener> mListener;
	private LocationManager mLocationManager;
	private Location mCurrentLocation;
	private Timer mTimer;


	public Geolocation(LocationManager locationManager, GeolocationListener listener)
	{
		mLocationManager = locationManager; // (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE); 
		mListener = new WeakReference<>(listener);
		mTimer = new Timer();
		init();
	}


	@Override
	public void onLocationChanged(Location location)
	{
		Logcat.d(location.getProvider() + " / " + location.getLatitude() + " / " + location.getLongitude() + " / " + new Date(location.getTime()).toString());

		// check location age
		long timeDelta = System.currentTimeMillis() - location.getTime();
		if(timeDelta > LOCATION_AGE)
		{
			Logcat.d("gotten location is too old");
			// gotten location is too old
			return;
		}

		// return location
		mCurrentLocation = new Location(location);
		stop();
		GeolocationListener listener = mListener.get();
		if(listener != null && location != null) listener.onGeolocationRespond(Geolocation.this, mCurrentLocation);
	}


	@Override
	public void onProviderDisabled(String provider)
	{
		Logcat.d(provider);
	}


	@Override
	public void onProviderEnabled(String provider)
	{
		Logcat.d(provider);
	}


	@Override
	public void onStatusChanged(String provider, int status, Bundle extras)
	{
		Logcat.d(provider);
		switch(status)
		{
			case LocationProvider.OUT_OF_SERVICE:
				Logcat.d("status OUT_OF_SERVICE");
				break;
			case LocationProvider.TEMPORARILY_UNAVAILABLE:
				Logcat.d("status TEMPORARILY_UNAVAILABLE");
				break;
			case LocationProvider.AVAILABLE:
				Logcat.d("status AVAILABLE");
				break;
		}
	}


	public void stop()
	{
		Logcat.d("");
		if(mTimer != null) mTimer.cancel();
		if(mLocationManager != null)
		{
			mLocationManager.removeUpdates(this);
			mLocationManager = null;
		}
	}


	private void init()
	{
		// get last known location
		Location lastKnownLocation = getLastKnownLocation(mLocationManager);

		// try to listen last known location
		if(lastKnownLocation != null)
		{
			onLocationChanged(lastKnownLocation);
		}

		if(mCurrentLocation == null)
		{
			// start timer to check timeout
			TimerTask task = new TimerTask()
			{
				public void run()
				{
					if(mCurrentLocation == null)
					{
						Logcat.d("timeout");
						stop();
						GeolocationListener listener = mListener.get();
						if(listener != null) listener.onGeolocationFail(Geolocation.this);
					}
				}
			};
			mTimer.schedule(task, LOCATION_TIMEOUT);

			// register location updates
			try
			{
				mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0L, 0.0F, this);
			}
			catch(IllegalArgumentException e)
			{
				e.printStackTrace();
			}
			try
			{
				mLocationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0L, 0.0F, this);
			}
			catch(IllegalArgumentException e)
			{
				e.printStackTrace();
			}
		}
	}


	// returns last known freshest location from network or GPS
	private Location getLastKnownLocation(LocationManager locationManager)
	{
		Logcat.d("");

		Location locationNet = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
		Location locationGps = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

		long timeNet = 0L;
		long timeGps = 0L;

		if(locationNet != null)
		{
			timeNet = locationNet.getTime();
		}

		if(locationGps != null)
		{
			timeGps = locationGps.getTime();
		}

		if(timeNet > timeGps) return locationNet;
		else return locationGps;
	}
}