How to retrieve the GPS location in coordinates from all users of the application?

Question

How to retrieve the GPS location in coordinates from all users of the application?

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#1 by (21 votes)

21

Explanation / Scenario:

I'm developing an application that should redeem users' location in real time, and these users aware of this, will also have access to the location of other users, on a map, to find themselves:

This location must be in real time, because all users have access to the map, and use it to find each other.

Question:

How do I get my application to real-time retrieve this location from all users (in coordinates) so that I can then use these coordinates and show the location on each user's map?

Note:

I'm not asking for an entire application, or doing one for me, I just want to know how to retrieve the coordinate of each application user :) but if they want to respond more fully including the part that shows the user with such a coordinate on the map, it would be extremely useful!

android gps

asked by anonymous 15.04.2014 / 21:27

1 answer

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score 21 · Accepted Answer

If what you want is a ready app, click here , otherwise, adapt the code below.

Initial kick:

There are several examples on the web, but I started with a SOen's own answer :

First of all, this has to be in the application manifest:

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

Example use of class below:

LocationResult locationResult = new LocationResult(){
    @Override
    public void gotLocation(Location location){
        //Usar a localizacao aqui!
    }
};
MyLocation myLocation = new MyLocation();
myLocation.getLocation(this, locationResult);

MyLocation class:

import java.util.Timer;
import java.util.TimerTask;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;

public class MyLocation {
    Timer timer1;
    LocationManager lm;
    LocationResult locationResult;
    boolean gps_enabled=false;
    boolean network_enabled=false;

    public boolean getLocation(Context context, LocationResult result)
    {
        //É usado o callback LocationResult para passar as coordenadas para o codigo do usuario.
        locationResult=result;
        if(lm==null)
            lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);

        //se o provedor de localizacao nao estiver habilitado, teremos uma excecao.
        try{gps_enabled=lm.isProviderEnabled(LocationManager.GPS_PROVIDER);}catch(Exception ex){}
        try{network_enabled=lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);}catch(Exception ex){}

        //Codigo para nao tentar fazer a leitura sem provedor de localizacao disponivel
        if(!gps_enabled && !network_enabled)
            return false;

        if(gps_enabled)
            lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListenerGps);
        if(network_enabled)
            lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListenerNetwork);
        timer1=new Timer();
        timer1.schedule(new GetLastLocation(), 20000);
        return true;
    }

    LocationListener locationListenerGps = new LocationListener() {
        public void onLocationChanged(Location location) {
            timer1.cancel();
            locationResult.gotLocation(location);
            lm.removeUpdates(this);
            lm.removeUpdates(locationListenerNetwork);
        }
        public void onProviderDisabled(String provider) {}
        public void onProviderEnabled(String provider) {}
        public void onStatusChanged(String provider, int status, Bundle extras) {}
    };

    LocationListener locationListenerNetwork = new LocationListener() {
        public void onLocationChanged(Location location) {
            timer1.cancel();
            locationResult.gotLocation(location);
            lm.removeUpdates(this);
            lm.removeUpdates(locationListenerGps);
        }
        public void onProviderDisabled(String provider) {}
        public void onProviderEnabled(String provider) {}
        public void onStatusChanged(String provider, int status, Bundle extras) {}
    };

    class GetLastLocation extends TimerTask {
        @Override
        public void run() {
             lm.removeUpdates(locationListenerGps);
             lm.removeUpdates(locationListenerNetwork);

             Location net_loc=null, gps_loc=null;
             if(gps_enabled)
                 gps_loc=lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
             if(network_enabled)
                 net_loc=lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

             //se tiver os dois valores, usar o mais atualizado
             if(gps_loc!=null && net_loc!=null){
                 if(gps_loc.getTime()>net_loc.getTime())
                     locationResult.gotLocation(gps_loc);
                 else
                     locationResult.gotLocation(net_loc);
                 return;
             }

             if(gps_loc!=null){
                 locationResult.gotLocation(gps_loc);
                 return;
             }
             if(net_loc!=null){
                 locationResult.gotLocation(net_loc);
                 return;
             }
             locationResult.gotLocation(null);
        }
    }

    public static abstract class LocationResult{
        public abstract void gotLocation(Location location);
    }
}

Note: In the original thread there are several interesting points and modifications, I recommend reading.