PlacesRepository: Add methods for fetching places in geo bounds

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

@@ -5,6 +5,7 @@ import androidx.room.Insert;
 import androidx.room.OnConflictStrategy;
 import androidx.room.Query;
 import io.reactivex.Completable;
+import java.util.List;
 
 /**
  * Data Access Object (DAO) for accessing the Place entity in the database.
@@ -32,6 +33,11 @@ public abstract class PlaceDao {
     @Query("SELECT * from place WHERE entityID=:entity")
     public abstract Place getPlace(String entity);
 
+    @Query("SELECT * from place WHERE latitude>=:latBegin AND longitude>=:lngBegin "
+        + "AND latitude<:latEnd AND longitude<:lngEnd")
+    public abstract List<Place> fetchPlaces(double latBegin, double lngBegin,
+        double latEnd, double lngEnd);
+
     /**
      * Saves a Place object asynchronously into the database.
      */

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

@@ -1,6 +1,7 @@
 package fr.free.nrw.commons.nearby;
 
 import io.reactivex.Completable;
+import java.util.List;
 import javax.inject.Inject;
 
 /**
@@ -26,6 +27,11 @@ public class PlacesLocalDataSource {
         return placeDao.getPlace(entityID);
     }
 
+    public List<Place> fetchPlaces(final double latBegin, final double lngBegin,
+        final double latEnd, final double lngEnd) {
+        return placeDao.fetchPlaces(latBegin, lngBegin, latEnd, lngEnd);
+    }
+
     /**
      * Saves a Place object asynchronously into the database.
      *

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

@@ -4,6 +4,7 @@ import fr.free.nrw.commons.contributions.Contribution;
 import fr.free.nrw.commons.location.LatLng;
 import io.reactivex.Completable;
 import io.reactivex.schedulers.Schedulers;
+import java.util.List;
 import javax.inject.Inject;
 
 /**
@@ -39,6 +40,11 @@ public class PlacesRepository {
         return localDataSource.fetchPlace(entityID);
     }
 
+    public List<Place> fetchPlaces(final double latBegin, final double lngBegin,
+        final double latEnd, final double lngEnd) {
+        return localDataSource.fetchPlaces(latBegin, lngBegin, latEnd, lngEnd);
+    }
+
     /**
      * Clears the Nearby cache on an IO thread.
      *

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

@@ -54,6 +54,7 @@ class NearbyParentFragmentPresenter
 
     private var placeSearchJob: Job? = null
     private var isSearchInProgress = false
+    private var localPlaceSearchJob: Job? = null
 
     private val clickedPlaces = CopyOnWriteArrayList<Place>()
 
@@ -495,8 +496,9 @@ class NearbyParentFragmentPresenter
     @Override
     override fun handleMapScrolled(scope: LifecycleCoroutineScope?) {
         scope ?: return
+
         placeSearchJob?.cancel()
-        placeSearchJob = scope.launch {
+        placeSearchJob = scope.launch(Dispatchers.Main) {
             delay(SCROLL_DELAY)
             if (!isSearchInProgress) {
                 isSearchInProgress = true; // search executing flag
@@ -508,6 +510,12 @@ class NearbyParentFragmentPresenter
                 }
             }
         }
+
+        localPlaceSearchJob?.cancel()
+        localPlaceSearchJob = scope.launch {
+            delay(LOCAL_SCROLL_DELAY)
+
+        }
     }
 
     /**
@@ -583,6 +591,7 @@ class NearbyParentFragmentPresenter
 
     companion object {
         private const val SCROLL_DELAY = 800L; // Delay for debounce of onscroll, in milliseconds.
+        private const val LOCAL_SCROLL_DELAY = 200L; // SCROLL_DELAY but for local db place search
         private val DUMMY = Proxy.newProxyInstance(
             NearbyParentFragmentContract.View::class.java.getClassLoader(),
             arrayOf<Class<*>>(NearbyParentFragmentContract.View::class.java),