Add a dialog to prompt user if location is off in Nearby when Locate me button is pressed.

app/src/main/java/fr/free/nrw/commons/location/LocationServiceManager.java

@@ -6,7 +6,6 @@
 import android.location.LocationListener;
 import android.location.LocationManager;
 import android.os.Bundle;
-
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -214,6 +213,14 @@ public void onProviderDisabled(String provider) {
         Timber.d("Provider %s disabled", provider);
     }
 
+    public boolean isNetworkProviderEnabled() {
+        return locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
+    }
+
+    public boolean isGPSProviderEnabled() {
+        return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
+    }
+
     public enum LocationChangeType{
         LOCATION_SIGNIFICANTLY_CHANGED, //Went out of borders of nearby markers
         LOCATION_SLIGHTLY_CHANGED,      //User might be walking or driving

app/src/main/java/fr/free/nrw/commons/nearby/contract/NearbyParentFragmentContract.java

@@ -28,6 +28,8 @@ interface View {
         void setFABRecenterAction(android.view.View.OnClickListener onClickListener);
         void animateFABs();
         void recenterMap(LatLng curLatLng);
+        void showLocationOffDialog();
+        void openLocationSettings();
         void hideBottomSheet();
         void hideBottomDetailsSheet();
         void displayBottomSheetWithInfo(Marker marker);

app/src/main/java/fr/free/nrw/commons/nearby/fragments/NearbyParentFragment.java

@@ -6,9 +6,11 @@
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
+import android.content.pm.PackageManager;
 import android.content.res.Configuration;
 import android.graphics.Bitmap;
 import android.os.Bundle;
+import android.provider.Settings;
 import android.util.Log;
 import android.view.Gravity;
 import android.view.LayoutInflater;
@@ -54,6 +56,7 @@
 import com.mapbox.mapboxsdk.maps.UiSettings;
 import com.pedrogomez.renderers.RVRendererAdapter;
 
+import fr.free.nrw.commons.utils.DialogUtil;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
@@ -1238,6 +1241,9 @@ private void setMapMarkerActions(Marker selectedMarker) {
     @Override
     public void recenterMap(fr.free.nrw.commons.location.LatLng curLatLng) {
         if (curLatLng == null) {
+            if (!(locationManager.isNetworkProviderEnabled() || locationManager.isGPSProviderEnabled())) {
+                showLocationOffDialog();
+            }
             return;
         }
         addCurrentLocationMarker(curLatLng);
@@ -1268,6 +1274,28 @@ public void recenterMap(fr.free.nrw.commons.location.LatLng curLatLng) {
         mapBox.animateCamera(CameraUpdateFactory.newCameraPosition(position), 1000);
     }
 
+    @Override
+    public void showLocationOffDialog() {
+        // This creates a dialog box that prompts the user to enable location
+        DialogUtil
+            .showAlertDialog(getActivity(), getString(R.string.ask_to_turn_location_on), getString(R.string.nearby_needs_location),
+                getString(R.string.yes), getString(R.string.no),  this::openLocationSettings, null);
+    }
+
+    @Override
+    public void openLocationSettings() {
+        // This method opens the location settings of the device along with a followup toast.
+        Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
+        PackageManager packageManager = getActivity().getPackageManager();
+
+        if (intent.resolveActivity(packageManager)!= null) {
+            startActivity(intent);
+            Toast.makeText(getContext(), R.string.recommend_high_accuracy_mode, Toast.LENGTH_LONG).show();
+        } else {
+            Toast.makeText(getContext(), R.string.cannot_open_location_settings, Toast.LENGTH_LONG).show();
+        }
+    }
+
     @Override
     public void hideBottomSheet() {
         bottomSheetListBehavior.setState(BottomSheetBehavior.STATE_HIDDEN);

app/src/main/res/values/strings.xml

@@ -602,4 +602,10 @@ Upload your first media by tapping on the add button.</string>
   <string name="theme_default_name">Default</string>
   <string name="theme_dark_name">Dark</string>
   <string name="theme_light_name">Light</string>
+
+  <string name="cannot_open_location_settings">Failed to open location settings. Please turn on location manually</string>
+  <string name="recommend_high_accuracy_mode">For best results, choose the High Accuracy mode.</string>
+  <string name="ask_to_turn_location_on">Turn on location?</string>
+  <string name="nearby_needs_location">Nearby needs location enabled to work properly</string>
+
 </resources>