show/hide filter bar, show/hide headers

lib/model/collection_lens.dart

@@ -2,9 +2,11 @@ import 'dart:async';
 import 'dart:collection';
 
 import 'package:aves/model/collection_source.dart';
+import 'package:aves/model/filters/album.dart';
 import 'package:aves/model/filters/filters.dart';
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/settings.dart';
+import 'package:aves/utils/change_notifier.dart';
 import 'package:collection/collection.dart';
 import 'package:flutter/foundation.dart';
 
@@ -13,6 +15,7 @@ class CollectionLens with ChangeNotifier {
   final Set<CollectionFilter> filters;
   GroupFactor groupFactor;
   SortFactor sortFactor;
+  final AChangeNotifier filterChangeNotifier = AChangeNotifier();
 
   List<ImageEntry> _filteredEntries;
   List<StreamSubscription> _subscriptions = [];
@@ -63,11 +66,24 @@ class CollectionLens with ChangeNotifier {
 
   int get entryCount => _filteredEntries.length;
 
-  int get imageCount => _filteredEntries.where((entry) => !entry.isVideo).length;
+  List<ImageEntry> _sortedEntries;
 
-  int get videoCount => _filteredEntries.where((entry) => entry.isVideo).length;
+  List<ImageEntry> get sortedEntries {
+    if (_sortedEntries == null) {
+      _sortedEntries = List.unmodifiable(sections.entries.expand((e) => e.value));
+    }
+    return _sortedEntries;
+  }
 
-  List<ImageEntry> get sortedEntries => List.unmodifiable(sections.entries.expand((e) => e.value));
+  bool get showHeaders {
+    if (sortFactor == SortFactor.size) return false;
+
+    final albumSections = sortFactor == SortFactor.name || (sortFactor == SortFactor.date && groupFactor == GroupFactor.album);
+    final filterByAlbum = filters.any((f) => f is AlbumFilter);
+    if (albumSections && filterByAlbum) return false;
+
+    return true;
+  }
 
   Object heroTag(ImageEntry entry) => '$hashCode${entry.uri}';
 
@@ -90,6 +106,7 @@ class CollectionLens with ChangeNotifier {
     _applyFilters();
     _applySort();
     _applyGroup();
+    filterChangeNotifier.notifyListeners();
   }
 
   void sort(SortFactor sortFactor) {
@@ -156,6 +173,7 @@ class CollectionLens with ChangeNotifier {
         sections = Map.unmodifiable(SplayTreeMap.of(byAlbum, compare));
         break;
     }
+    _sortedEntries = null;
     notifyListeners();
   }
 

lib/model/image_entry.dart

@@ -30,7 +30,7 @@ class ImageEntry {
   AddressDetails addressDetails;
 
   final AChangeNotifier imageChangeNotifier = AChangeNotifier(), metadataChangeNotifier = AChangeNotifier(), addressChangeNotifier = AChangeNotifier();
-  final isFavouriteNotifier = ValueNotifier(false);
+  final ValueNotifier<bool> isFavouriteNotifier = ValueNotifier(false);
 
   ImageEntry({
     this.uri,

lib/widgets/album/collection_app_bar.dart

@@ -69,12 +69,17 @@ class _CollectionAppBarState extends State<CollectionAppBar> with SingleTickerPr
       valueListenable: stateNotifier,
       builder: (context, state, child) {
         debugPrint('$runtimeType builder state=$state');
-        return SliverAppBar(
+        return Consumer<CollectionLens>(
+          builder: (context, collection, child) => AnimatedBuilder(
+            animation: collection.filterChangeNotifier,
+            builder: (context, child) => SliverAppBar(
               leading: _buildAppBarLeading(),
               title: _buildAppBarTitle(),
               actions: _buildActions(),
-          bottom: FilterBar(),
+              bottom: collection.filters.isNotEmpty ? FilterBar() : null,
               floating: true,
+            ),
+          ),
         );
       },
     );

lib/widgets/album/collection_section.dart

@@ -14,12 +14,14 @@ class SectionSliver extends StatelessWidget {
   final CollectionLens collection;
   final dynamic sectionKey;
   final int columnCount;
+  final bool showHeader;
 
   const SectionSliver({
     Key key,
     @required this.collection,
     @required this.sectionKey,
     @required this.columnCount,
+    @required this.showHeader,
   }) : super(key: key);
 
   @override
@@ -49,7 +51,8 @@ class SectionSliver extends StatelessWidget {
       ),
     );
 
-    return SliverStickyHeader(
+    return showHeader
+        ? SliverStickyHeader(
             header: SectionHeader(
               collection: collection,
               sections: sections,
@@ -57,7 +60,8 @@ class SectionSliver extends StatelessWidget {
             ),
             sliver: sliver,
             overlapsContent: false,
-    );
+          )
+        : sliver;
   }
 }
 
@@ -133,7 +137,7 @@ class SectionHeader extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    Widget header = const SizedBox.shrink();
+    Widget header;
     switch (collection.sortFactor) {
       case SortFactor.date:
         if (collection.sortFactor == SortFactor.date) {
@@ -156,9 +160,11 @@ class SectionHeader extends StatelessWidget {
         header = _buildAlbumSectionHeader(context);
         break;
     }
-    return IgnorePointer(
+    return header != null
+        ? IgnorePointer(
             child: header,
-    );
+          )
+        : const SizedBox.shrink();
   }
 
   Widget _buildAlbumSectionHeader(BuildContext context) {

lib/widgets/album/search/search_delegate.dart

@@ -59,7 +59,6 @@ class ImageSearchDelegate extends SearchDelegate<CollectionFilter> {
       child: ValueListenableBuilder<String>(
           valueListenable: expandedSectionNotifier,
           builder: (context, expandedSection, child) {
-            debugPrint('builder expandedSection=$expandedSection');
             return ListView(
               children: [
                 _buildFilterRow(

lib/widgets/album/thumbnail_collection.dart

@@ -25,6 +25,7 @@ class ThumbnailCollection extends StatelessWidget {
     final collection = Provider.of<CollectionLens>(context);
     final sections = collection.sections;
     final sectionKeys = sections.keys.toList();
+    final showHeaders = collection.showHeaders;
 
     double topPadding = 0;
     if (appBar != null) {
@@ -64,6 +65,7 @@ class ThumbnailCollection extends StatelessWidget {
                           collection: collection,
                           sectionKey: sectionKey,
                           columnCount: columnCount,
+                          showHeader: showHeaders,
                         )),
                     SliverToBoxAdapter(
                       child: Selector<MediaQueryData, double>(