Fix #1921, missing information about internet connectivity on nearby page

The reported issue is that in the Nearby activity, the app does not communicate that there is no internet connection. On investigation, it appears that a toast message does briefly display "No internet connection". It looks like other activities have implemented this same message within the snackbar instead. In order to have a consistent style of communication to the user, I removed the toast message and replace it with the snackbar message, as implemented in NotificationActivity.java.

Author: spelka

app/src/main/java/fr/free/nrw/commons/nearby/NearbyActivity.java

@@ -13,6 +13,7 @@
 import android.os.Handler;
 import android.support.annotation.NonNull;
 import android.support.design.widget.BottomSheetBehavior;
+import android.support.design.widget.Snackbar;
 import android.support.v4.app.FragmentTransaction;
 import android.support.v7.app.AlertDialog;
 import android.view.Menu;
@@ -371,15 +372,17 @@ public void onPause() {
 
     private void addNetworkBroadcastReceiver() {
         IntentFilter intentFilter = new IntentFilter(NETWORK_INTENT_ACTION);
+        Snackbar snackbar = Snackbar.make(transparentView , R.string.no_internet, Snackbar.LENGTH_INDEFINITE);
 
         broadcastReceiver = new BroadcastReceiver() {
 
             @Override
             public void onReceive(Context context, Intent intent) {
                 if (NetworkUtils.isInternetConnectionEstablished(NearbyActivity.this)) {
                     refreshView(LOCATION_SIGNIFICANTLY_CHANGED);
+                    snackbar.dismiss();
                 } else {
-                    ViewUtil.showLongToast(NearbyActivity.this, getString(R.string.no_internet));
+                    snackbar.show();
                 }
             }
         };