in LocationUpdates/app/src/main/java/com/google/android/gms/location/sample/locationupdates/MainActivity.java [433:444]
public void onResume() {
super.onResume();
// Within {@code onPause()}, we remove location updates. Here, we resume receiving
// location updates if the user has requested them.
if (mRequestingLocationUpdates && checkPermissions()) {
startLocationUpdates();
} else if (!checkPermissions()) {
requestPermissions();
}
updateUI();
}