How to send my GPS location (Latitude,Longitude) in a query string?

Question

I need to make a simple application for android that send the location of my smartphone every 25 seconds to a Web-app. My Web-app is online and right now i can pass the value manually like this:

http://mywebapp.com/coordinates/create?latitude=18.463108&longitude=-69.929117

I'm an absolute beginner to Android development, so try to explain me step by step.

Answer 1

After doing a deep research, I found what I think is the easiest way to send GPS location (Latitude,Longitude) in a query string. Maybe there's no shorter code in the web than this. So we'll do this in 2 steps:

1. First add this permissions to the AndroidManifest.xml

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

2. Now the code in your MainActivity.java inside the class public class MainActivity extends Activity { }

   public class MainActivity extends Activity {
   
       public double latitude;
       public double longitude;
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
   
           /* Use the LocationManager class to obtain GPS locations */
           LocationManager mlocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
           LocationListener mlocListener = new MyLocationListener();
           mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
       }
   
       /* Class My Location Listener */
   
       public class MyLocationListener implements LocationListener {
   
           @Override
           public void onLocationChanged(Location loc) {
               latitude = loc.getLatitude();
               longitude = loc.getLongitude();
               String Text = "My current Latitude = " + latitude  + " Longitude = " + longitude;
               Toast.makeText( getApplicationContext(),Text,Toast.LENGTH_SHORT).show();
   
               SendQueryString(); // for send the  Query String of latitude and logintude to the webapp.
           }
   
   
   
           @Override
           public void onProviderDisabled(String provider) {   
               Toast.makeText( getApplicationContext(),"Gps Disabled",Toast.LENGTH_SHORT ).show();
           }
   
   
           @Override
           public void onProviderEnabled(String provider) {
               Toast.makeText( getApplicationContext(),"Gps Enabled",Toast.LENGTH_SHORT).show();
           }
   
   
           @Override
           public void onStatusChanged(String provider, int status, Bundle extras) {
           }
   
       }/* End of Class MyLocationListener */
   
   
       public void SendQueryString() {
           new Thread() {  
               public void run() {
   
                   String url = "http://mywebapp.com/coordinates/create?latitude=" + latitude +"&longitude=" + longitude;
   
                   try {
                       HttpClient Client = new DefaultHttpClient();
                       HttpGet httpget = new HttpGet(url);
                       Client.execute(httpget);
                   }
                   catch(Exception ex) {
                       String fail = "Fail!";
                       Toast.makeText( getApplicationContext(),fail,Toast.LENGTH_SHORT).show();
                   }
               }
           }.start();
       }
   }
   

NOTE: As you can see I'm using new Thread() { public void run() {/*code here*/}}.start(); in the function SendQueryString(), that's because we're trying to make a request to a server, so in Android you can't make a request to a server in the principal Thread, where the graphics and principal process are. In fact it'll return an error if you try to make a request in the principal Thread.

Answer 2

First get location:

LocationManager locMan = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locMan.requestLocationUpdates(
    LocationManager.GPS_PROVIDER, 0, 0, location listener);

The first zero represents the time interval of the location updating The second one represents the distance interval of the updating .. configure as you will.

And in the listener:

public void onLocationChanged(Location location) {
if (location != null) {
    double lat = location.getLatitude();
    double long = location.getLongitude();
   }
}

You just have to a make an http request with that link like the following:

String url = "http://mywebapp.com/coordinates/createlatitude=" + lat +"&longitude=" + long;
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
httpClient.execute(httpGet);