Getting the user's coordinates using Geofence will not work

Question

What I want to do is get the users location when the app loads and then when a button is clicked, I want the app to check if the distance of the user is within the radius of my desired location then it will do something

location is what I am having issues with...I am trying to get the user's location in the simplest way because I only need it to check if the user is at or "around" the location

here is my code to get the user's location(complies but the app crashes):

if (ContextCompat.checkSelfPermission(this,
    Manifest.permission.READ_CONTACTS)
    != PackageManager.PERMISSION_GRANTED) {

    LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

    Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);


    double longitude = location.getLongitude();
    double latitude = location.getLatitude();

    List<Geofence> mGeofenceList = new ArrayList<Geofence>();

    mGeofenceList.add(new Geofence.Builder()
        .setRequestId("Request ID")
        .setCircularRegion(latitude, longitude, 480f)
        .setExpirationDuration(300000) // duration is in millis (5mins)
        .setTransitionTypes(Geofence.GEOFENCE_TRANSITION_ENTER | Geofence.GEOFENCE_TRANSITION_EXIT)
        .build());
}

Answer 1

Try using Location Listener like below.

public class MainActivity extends Activity implements LocationListener{
protected LocationManager locationManager;
protected LocationListener locationListener;
protected Context context;
TextView txtLat;
String lat;
String provider;
protected String latitude,longitude; 
protected boolean gps_enabled,network_enabled;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txtLat = (TextView) findViewById(R.id.textview1);

locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
}
@Override
public void onLocationChanged(Location location) {
txtLat = (TextView) findViewById(R.id.textview1);
double lat = location.getLatitude(); 
double longi = location.getLongitude();
txtLat.setText("Latitude:" + location.getLatitude() + ", Longitude:" +    location.getLongitude());
}

@Override
public void onProviderDisabled(String provider) {
Log.d("Latitude","disable");
}

@Override
public void onProviderEnabled(String provider) {
Log.d("Latitude","enable");
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
Log.d("Latitude","status");
}
}

Permissions:

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

you will get the current lat and long values in the onLocationChanged() method. Add this lat and long values to your mGeofenceList list.