Mostly implement search this area methods, not tested yet even once

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

@@ -6,6 +6,7 @@ import android.os.Bundle;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 import com.mapbox.mapboxsdk.annotations.BaseMarkerOptions;
 import com.mapbox.mapboxsdk.maps.MapView;
+import com.mapbox.mapboxsdk.maps.MapboxMap;
 
 import java.util.List;
 
@@ -47,6 +48,7 @@ public interface NearbyMapContract {
         void updateMarker(boolean isBookmarked, Place place);
         LatLng getCameraTarget();
         void viewsAreSet(NearbyParentFragmentContract.ViewsAreReadyCallback viewsAreReadyCallback);
+        void addOnCameraMoveListener(MapboxMap.OnCameraMoveListener onCameraMoveListener);
     }
 
     interface UserActions extends NearbyElementContract.UserActions {

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

@@ -1,6 +1,10 @@
 package fr.free.nrw.commons.nearby.mvp.contract;
 
 
+import android.widget.Button;
+
+import com.mapbox.mapboxsdk.maps.MapboxMap;
+
 import fr.free.nrw.commons.location.LatLng;
 import fr.free.nrw.commons.location.LocationServiceManager;
 
@@ -19,6 +23,9 @@ public interface NearbyParentFragmentContract {
         void listOptionMenuItemClicked();
         void  populatePlaces(LatLng curlatLng, LatLng searchLatLng);
         boolean isBottomSheetExpanded();
+        void addSearchThisAreaButtonAction();
+        void setSearchThisAreaButtonVisibility(boolean isVisible);
+        void setSearchThisAreaProgressVisibility(boolean isVisible);
     }
 
     interface UserActions {
@@ -32,7 +39,7 @@ public interface NearbyParentFragmentContract {
 
         void lockNearby(boolean isNearbyLocked);
 
-        void addMapMovementListeners();
+        MapboxMap.OnCameraMoveListener onCameraMove(LatLng cameraTarget);
     }
     
     interface ViewsAreReadyCallback {

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

@@ -409,6 +409,11 @@ public class NearbyMapFragment extends CommonsDaggerSupportFragment implements N
         this.viewsAreReadyCallback.nearbyFragmentAndMapViewReady();
     }
 
+    @Override
+    public void addOnCameraMoveListener(MapboxMap.OnCameraMoveListener onCameraMoveListener) {
+        mapboxMap.addOnCameraMoveListener(onCameraMoveListener);
+    }
+
     @Override
     public void showPlaces() {
 

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

@@ -119,12 +119,6 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         return view;
     }
 
-    @Override
-    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
-        super.onViewCreated(view, savedInstanceState);
-        addSearchThisAreaButtonAction();
-    }
-
     @Override
     public void onResume() {
         super.onResume();
@@ -142,15 +136,28 @@ public class NearbyParentFragment extends CommonsDaggerSupportFragment
         Timber.d("Child fragment attached");
     }
 
+    @Override
     public void addSearchThisAreaButtonAction() {
-        searchThisAreaButton.setOnClickListener(view -> {
+        searchThisAreaButton.setOnClickListener(nearbyParentFragmentPresenter.onSearchThisAreaClicked());
-            // Lock map operations during search this area operation
+    }
-            nearbyParentFragmentPresenter.lockNearby(true);
+
-            searchThisAreaButtonProgressBar.setVisibility(View.VISIBLE);
+    @Override
+    public void setSearchThisAreaButtonVisibility(boolean isVisible) {
+        if (isVisible) {
+            searchThisAreaButton.setVisibility(View.VISIBLE);
+        } else {
             searchThisAreaButton.setVisibility(View.GONE);
-            nearbyParentFragmentPresenter.updateMapAndList(SEARCH_CUSTOM_AREA,
+        }
-                    NearbyParentFragment.this.nearbyParentFragmentPresenter.getCameraTarget());
+    }
-        });
+
+
+    @Override
+    public void setSearchThisAreaProgressVisibility(boolean isVisible) {
+        if (isVisible) {
+            searchThisAreaButtonProgressBar.setVisibility(View.VISIBLE);
+        } else {
+            searchThisAreaButtonProgressBar.setVisibility(View.GONE);
+        }
     }
 
     @Override

app/src/main/java/fr/free/nrw/commons/nearby/mvp/presenter/NearbyParentFragmentPresenter.java

@@ -2,7 +2,11 @@ package fr.free.nrw.commons.nearby.mvp.presenter;
 
 import android.util.Log;
 import android.view.View;
+import android.widget.Button;
 
+import com.mapbox.mapboxsdk.maps.MapboxMap;
+
+import ch.qos.logback.core.util.LocationUtil;
 import fr.free.nrw.commons.R;
 import fr.free.nrw.commons.location.LatLng;
 import fr.free.nrw.commons.location.LocationServiceManager;
@@ -10,6 +14,8 @@ import fr.free.nrw.commons.location.LocationUpdateListener;
 import fr.free.nrw.commons.nearby.NearbyController;
 import fr.free.nrw.commons.nearby.mvp.contract.NearbyMapContract;
 import fr.free.nrw.commons.nearby.mvp.contract.NearbyParentFragmentContract;
+import fr.free.nrw.commons.utils.LocationUtils;
+import fr.free.nrw.commons.utils.NetworkUtils;
 import fr.free.nrw.commons.wikidata.WikidataEditListener;
 import io.reactivex.Observable;
 import io.reactivex.android.schedulers.AndroidSchedulers;
@@ -35,6 +41,7 @@ public class NearbyParentFragmentPresenter
 
     boolean nearbyViewsAreReady;
     boolean onTabSelected;
+    boolean searchingThisArea;
 
     private LocationServiceManager locationServiceManager;
 
@@ -45,6 +52,10 @@ public class NearbyParentFragmentPresenter
         this.nearbyMapFragmentView = nearbyMapFragmentView;
         this.nearbyMapFragmentView.viewsAreSet(this);
         this.locationServiceManager = locationServiceManager;
+
+        // Add on map camera moved listener after making sure presenter is ready
+        this.nearbyParentFragmentView.addSearchThisAreaButtonAction();
+        this.nearbyMapFragmentView.addOnCameraMoveListener(onCameraMove(getCameraTarget()));
     }
 
     /**
@@ -131,8 +142,55 @@ public class NearbyParentFragmentPresenter
      * this area button to search nearby places for other locations
      */
     @Override
-    public void addMapMovementListeners() {
+    public MapboxMap.OnCameraMoveListener onCameraMove(LatLng cameraTarget) {
+        return new MapboxMap.OnCameraMoveListener() {
+            @Override
+            public void onCameraMove() {
+                // If our nearby markers are calculated at least once
+                if (NearbyController.currentLocation != null) {
+                    if (nearbyParentFragmentView.isNetworkConnectionEstablished()) {
+                        nearbyParentFragmentView.setSearchThisAreaButtonVisibility(true);
+                    }
+                }
+            }
+        };
+    }
 
+    public View.OnClickListener onSearchThisAreaClicked() {
+        return new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                // Lock map operations during search this area operation
+                lockNearby(true);
+                nearbyParentFragmentView.setSearchThisAreaProgressVisibility(true);
+                // TODO: make this invisible at somewhere
+                nearbyParentFragmentView.setSearchThisAreaButtonVisibility(false);
+
+                if (searchCloseToCurrentLocation()){
+                    updateMapAndList(LOCATION_SIGNIFICANTLY_CHANGED,
+                            null);
+                } else {
+                    updateMapAndList(SEARCH_CUSTOM_AREA,
+                            getCameraTarget());
+                }
+            }
+        };
+    }
+
+    /**
+     * Returns true if search this area button is used around our current location, so that
+     * we can continue following our current location again
+     * @return Returns true if search this area button is used around our current location
+     */
+    public boolean searchCloseToCurrentLocation() {
+        double distance = LocationUtils.commonsLatLngToMapBoxLatLng(getCameraTarget())
+                .distanceTo(new com.mapbox.mapboxsdk.geometry.LatLng(NearbyController.currentLocation.getLatitude()
+                        , NearbyController.currentLocation.getLongitude()));
+        if (distance > NearbyController.searchedRadius*1000*3/4) {
+            return false;
+        } else {
+            return true;
+        }
     }
 
 
@@ -180,6 +238,7 @@ public class NearbyParentFragmentPresenter
 
         } else if (locationChangeType.equals(SEARCH_CUSTOM_AREA)) {
             nearbyParentFragmentView.populatePlaces(lastLocation, cameraTarget);
+            searchingThisArea = false;
         }
 
         else { // Means location changed slightly, ie user is walking or driving.