Dynamic album that reflects dir contents

lib/entity/album/provider.dart

@@ -4,6 +4,7 @@ import 'package:equatable/equatable.dart';
 import 'package:flutter/foundation.dart';
 import 'package:logging/logging.dart';
 import 'package:nc_photos/entity/album.dart';
+import 'package:nc_photos/entity/file.dart';
 import 'package:nc_photos/iterable_extension.dart';
 
 abstract class AlbumProvider with EquatableMixin {
@@ -15,6 +16,8 @@ abstract class AlbumProvider with EquatableMixin {
     switch (type) {
       case AlbumStaticProvider._type:
         return AlbumStaticProvider.fromJson(content.cast<String, dynamic>());
+      case AlbumDirProvider._type:
+        return AlbumDirProvider.fromJson(content.cast<String, dynamic>());
       default:
         _log.shout("[fromJson] Unknown type: $type");
         throw ArgumentError.value(type, "type");
@@ -25,6 +28,8 @@ abstract class AlbumProvider with EquatableMixin {
     String getType() {
       if (this is AlbumStaticProvider) {
         return AlbumStaticProvider._type;
+      } else if (this is AlbumDirProvider) {
+        return AlbumDirProvider._type;
       } else {
         throw StateError("Unknwon subtype");
       }
@@ -57,6 +62,9 @@ class AlbumStaticProvider extends AlbumProvider {
     );
   }
 
+  factory AlbumStaticProvider.of(Album parent) =>
+      (parent.provider as AlbumStaticProvider);
+
   @override
   toString({bool isDeep = false}) {
     final itemsStr =
@@ -83,3 +91,40 @@ class AlbumStaticProvider extends AlbumProvider {
 
   static const _type = "static";
 }
+
+class AlbumDirProvider extends AlbumProvider {
+  AlbumDirProvider({
+    @required this.dirs,
+  });
+
+  factory AlbumDirProvider.fromJson(Map<String, dynamic> json) {
+    return AlbumDirProvider(
+      dirs: (json["dirs"] as List)
+          .map((e) => File.fromJson(e.cast<String, dynamic>()))
+          .toList(),
+    );
+  }
+
+  @override
+  toString({bool isDeep = false}) {
+    return "$runtimeType {"
+        "dirs: ${dirs.map((e) => e.path).toReadableString()}, "
+        "}";
+  }
+
+  @override
+  get props => [
+        dirs,
+      ];
+
+  @override
+  _toContentJson() {
+    return {
+      "dirs": dirs.map((e) => e.toJson()).toList(),
+    };
+  }
+
+  final List<File> dirs;
+
+  static const _type = "dir";
+}

lib/iterable_extension.dart

@@ -21,4 +21,8 @@ extension IterableExtension<T> on Iterable<T> {
   /// equality function [equalFn]
   bool containsIf(T element, bool Function(T a, T b) equalFn) =>
       any((e) => equalFn(e, element));
+
+  /// Same as [contains] but uses [identical] to compare the objects
+  bool containsIdentical(T element) =>
+      containsIf(element, (a, b) => identical(a, b));
 }

lib/use_case/populate_album.dart

@@ -0,0 +1,48 @@
+import 'package:flutter/foundation.dart';
+import 'package:logging/logging.dart';
+import 'package:nc_photos/account.dart';
+import 'package:nc_photos/entity/album.dart';
+import 'package:nc_photos/entity/album/provider.dart';
+import 'package:nc_photos/entity/file.dart';
+import 'package:nc_photos/entity/file/data_source.dart';
+import 'package:nc_photos/use_case/scan_dir.dart';
+
+class PopulateAlbum {
+  Future<List<AlbumItem>> call(Account account, Album album) async {
+    if (album.provider is AlbumStaticProvider) {
+      _log.warning(
+          "[call] Populate only make sense for dynamic albums: ${album.name}");
+      return AlbumStaticProvider.of(album).items;
+    }
+    if (album.provider is AlbumDirProvider) {
+      return _populateDirAlbum(account, album);
+    } else {
+      throw ArgumentError(
+          "Unknown album provider: ${album.provider.runtimeType}");
+    }
+  }
+
+  Future<List<AlbumItem>> _populateDirAlbum(
+      Account account, Album album) async {
+    assert(album.provider is AlbumDirProvider);
+    final provider = album.provider as AlbumDirProvider;
+    final products = <AlbumItem>[];
+    for (final d in provider.dirs) {
+      final stream = ScanDir(FileRepo(FileCachedDataSource()))(account, d);
+      await for (final result in stream) {
+        if (result is Exception || result is Error) {
+          _log.shout(
+              "[_populateDirAlbum] Failed while scanning dir" +
+                  (kDebugMode ? ": $d" : ""),
+              result);
+          continue;
+        }
+        products.addAll(
+            (result as List).cast<File>().map((f) => AlbumFileItem(file: f)));
+      }
+    }
+    return products;
+  }
+
+  static final _log = Logger("use_case.populate_album.PopulateAlbum");
+}

lib/widget/album_grid_item.dart

@@ -8,6 +8,7 @@ class AlbumGridItem extends StatelessWidget {
     @required this.cover,
     @required this.title,
     this.subtitle,
+    this.isDynamic = false,
     this.isSelected = false,
     this.onTap,
     this.onLongPress,
@@ -45,10 +46,23 @@ class AlbumGridItem extends StatelessWidget {
                     ),
                 textAlign: TextAlign.start,
                 maxLines: 1,
+                overflow: TextOverflow.ellipsis,
               ),
             ],
           ),
         ),
+        if (isDynamic)
+          Padding(
+            padding: const EdgeInsets.all(16),
+            child: Align(
+              alignment: AlignmentDirectional.topEnd,
+              child: Icon(
+                Icons.auto_awesome,
+                size: 16,
+                color: Colors.white,
+              ),
+            ),
+          ),
         if (isSelected)
           Positioned.fill(
             child: Container(
@@ -86,6 +100,7 @@ class AlbumGridItem extends StatelessWidget {
   final Widget cover;
   final String title;
   final String subtitle;
+  final bool isDynamic;
   final bool isSelected;
   final VoidCallback onTap;
   final VoidCallback onLongPress;

lib/widget/album_viewer.dart

@@ -1,11 +1,9 @@
-import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:logging/logging.dart';
 import 'package:nc_photos/account.dart';
-import 'package:nc_photos/api/api.dart';
 import 'package:nc_photos/api/api_util.dart' as api_util;
 import 'package:nc_photos/entity/album.dart';
 import 'package:nc_photos/entity/album/provider.dart';
@@ -15,13 +13,12 @@ import 'package:nc_photos/exception_util.dart' as exception_util;
 import 'package:nc_photos/iterable_extension.dart';
 import 'package:nc_photos/k.dart' as k;
 import 'package:nc_photos/list_extension.dart';
-import 'package:nc_photos/pref.dart';
 import 'package:nc_photos/snack_bar_manager.dart';
 import 'package:nc_photos/theme.dart';
 import 'package:nc_photos/use_case/resync_album.dart';
 import 'package:nc_photos/use_case/update_album.dart';
+import 'package:nc_photos/widget/album_viewer_mixin.dart';
 import 'package:nc_photos/widget/photo_list_item.dart';
-import 'package:nc_photos/widget/popup_menu_zoom.dart';
 import 'package:nc_photos/widget/selectable_item_stream_list_mixin.dart';
 import 'package:nc_photos/widget/viewer.dart';
 import 'package:quiver/iterables.dart';
@@ -57,11 +54,13 @@ class AlbumViewer extends StatefulWidget {
 }
 
 class _AlbumViewerState extends State<AlbumViewer>
-    with WidgetsBindingObserver, SelectableItemStreamListMixin<AlbumViewer> {
+    with
+        WidgetsBindingObserver,
+        SelectableItemStreamListMixin<AlbumViewer>,
+        AlbumViewerMixin<AlbumViewer> {
   @override
   initState() {
     super.initState();
-    _thumbZoomLevel = Pref.inst().getAlbumViewerZoomLevel(0);
     _initAlbum();
   }
 
@@ -74,9 +73,6 @@ class _AlbumViewerState extends State<AlbumViewer>
     );
   }
 
-  @override
-  get itemStreamListCellSize => _thumbSize;
-
   void _initAlbum() {
     assert(widget.album.provider is AlbumStaticProvider);
     ResyncAlbum()(widget.account, widget.album).then((album) {
@@ -90,26 +86,17 @@ class _AlbumViewerState extends State<AlbumViewer>
         setState(() {
           _album = album;
           _transformItems();
-          _initCover();
+          initCover(widget.account, _backingFiles);
         });
       }
     });
   }
 
-  void _initCover() {
-    try {
-      final coverFile =
-          _backingFiles.firstWhere((element) => element.hasPreview);
-      _coverPreviewUrl = api_util.getFilePreviewUrl(widget.account, coverFile,
-          width: 1024, height: 600);
-    } catch (_) {}
-  }
-
   Widget _buildContent(BuildContext context) {
     if (_album == null) {
       return CustomScrollView(
         slivers: [
-          _buildNormalAppBar(context),
+          buildNormalAppBar(context, widget.account, widget.album),
           const SliverToBoxAdapter(
             child: const LinearProgressIndicator(),
           ),
@@ -137,104 +124,18 @@ class _AlbumViewerState extends State<AlbumViewer>
 
   Widget _buildAppBar(BuildContext context) {
     if (isSelectionMode) {
-      return _buildSelectionAppBar(context);
-    } else {
-      return _buildNormalAppBar(context);
-    }
-  }
-
-  Widget _buildSelectionAppBar(BuildContext context) {
-    return Theme(
-      data: Theme.of(context).copyWith(
-        appBarTheme: AppTheme.getContextualAppBarTheme(context),
-      ),
-      child: SliverAppBar(
-        pinned: true,
-        leading: IconButton(
-          icon: const Icon(Icons.close),
-          tooltip: MaterialLocalizations.of(context).closeButtonTooltip,
+      return buildSelectionAppBar(context, [
+        IconButton(
+          icon: const Icon(Icons.remove),
+          tooltip: AppLocalizations.of(context).removeSelectedFromAlbumTooltip,
           onPressed: () {
-            setState(() {
-              clearSelectedItems();
-            });
+            _onSelectionAppBarRemovePressed();
           },
-        ),
-        title: Text(AppLocalizations.of(context)
-            .selectionAppBarTitle(selectedListItems.length)),
-        actions: [
-          IconButton(
-            icon: const Icon(Icons.remove),
-            tooltip:
-                AppLocalizations.of(context).removeSelectedFromAlbumTooltip,
-            onPressed: () {
-              _onSelectionAppBarRemovePressed();
-            },
-          )
-        ],
-      ),
-    );
-  }
-
-  Widget _buildNormalAppBar(BuildContext context) {
-    Widget cover;
-    try {
-      if (_coverPreviewUrl != null) {
-        cover = Opacity(
-          opacity:
-              Theme.of(context).brightness == Brightness.light ? 0.25 : 0.35,
-          child: FittedBox(
-            clipBehavior: Clip.hardEdge,
-            fit: BoxFit.cover,
-            child: CachedNetworkImage(
-              imageUrl: _coverPreviewUrl,
-              httpHeaders: {
-                "Authorization":
-                    Api.getAuthorizationHeaderValue(widget.account),
-              },
-              filterQuality: FilterQuality.high,
-              errorWidget: (context, url, error) {
-                // just leave it empty
-                return Container();
-              },
-              imageRenderMethodForWeb: ImageRenderMethodForWeb.HttpGet,
-            ),
-          ),
-        );
-      }
-    } catch (_) {}
-
-    return SliverAppBar(
-      floating: true,
-      expandedHeight: 160,
-      flexibleSpace: FlexibleSpaceBar(
-        background: cover,
-        title: Text(
-          (_album ?? widget.album).name,
-          style: TextStyle(
-            color: AppTheme.getPrimaryTextColor(context),
-          ),
-        ),
-      ),
-      actions: [
-        PopupMenuButton(
-          icon: const Icon(Icons.zoom_in),
-          tooltip: AppLocalizations.of(context).zoomTooltip,
-          itemBuilder: (context) => [
-            PopupMenuZoom(
-              initialValue: _thumbZoomLevel,
-              minValue: 0,
-              maxValue: 2,
-              onChanged: (value) {
-                setState(() {
-                  _thumbZoomLevel = value.round();
-                });
-                Pref.inst().setAlbumViewerZoomLevel(_thumbZoomLevel);
-              },
-            ),
-          ],
-        ),
-      ],
-    );
+        )
+      ]);
+    } else {
+      return buildNormalAppBar(context, widget.account, _album);
+    }
   }
 
   void _onItemTap(int index) {
@@ -272,7 +173,7 @@ class _AlbumViewerState extends State<AlbumViewer>
       setState(() {
         _album = newAlbum;
         _transformItems();
-        _initCover();
+        initCover(widget.account, _backingFiles);
       });
     }).catchError((e, stacktrace) {
       _log.shout("[_onSelectionRemovePressed] Failed while updating album", e,
@@ -301,7 +202,7 @@ class _AlbumViewerState extends State<AlbumViewer>
         final f = _backingFiles[i];
 
         final previewUrl = api_util.getFilePreviewUrl(widget.account, f,
-            width: _thumbSize, height: _thumbSize);
+            width: thumbSize, height: thumbSize);
         if (file_util.isSupportedImageFormat(f)) {
           yield _ImageListItem(
             file: f,
@@ -353,26 +254,9 @@ class _AlbumViewerState extends State<AlbumViewer>
   static List<AlbumItem> _getAlbumItemsOf(Album a) =>
       AlbumStaticProvider.of(a).items;
 
-  int get _thumbSize {
-    switch (_thumbZoomLevel) {
-      case 1:
-        return 176;
-
-      case 2:
-        return 256;
-
-      case 0:
-      default:
-        return 112;
-    }
-  }
-
   Album _album;
   var _backingFiles = <File>[];
 
-  String _coverPreviewUrl;
-  var _thumbZoomLevel = 0;
-
   static final _log = Logger("widget.album_viewer._AlbumViewerState");
 }
 

lib/widget/album_viewer_mixin.dart

@@ -0,0 +1,141 @@
+import 'package:cached_network_image/cached_network_image.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+import 'package:nc_photos/account.dart';
+import 'package:nc_photos/api/api.dart';
+import 'package:nc_photos/api/api_util.dart' as api_util;
+import 'package:nc_photos/entity/album.dart';
+import 'package:nc_photos/entity/file.dart';
+import 'package:nc_photos/pref.dart';
+import 'package:nc_photos/theme.dart';
+import 'package:nc_photos/widget/popup_menu_zoom.dart';
+import 'package:nc_photos/widget/selectable_item_stream_list_mixin.dart';
+
+mixin AlbumViewerMixin<T extends StatefulWidget>
+    on SelectableItemStreamListMixin<T> {
+  @override
+  initState() {
+    super.initState();
+    _thumbZoomLevel = Pref.inst().getAlbumViewerZoomLevel(0);
+  }
+
+  @protected
+  File initCover(Account account, List<File> backingFiles) {
+    try {
+      final coverFile =
+          backingFiles.firstWhere((element) => element.hasPreview);
+      _coverPreviewUrl = api_util.getFilePreviewUrl(account, coverFile,
+          width: 1024, height: 600);
+      return coverFile;
+    } catch (_) {
+      return null;
+    }
+  }
+
+  @protected
+  Widget buildNormalAppBar(BuildContext context, Account account, Album album) {
+    Widget cover;
+    try {
+      if (_coverPreviewUrl != null) {
+        cover = Opacity(
+          opacity:
+              Theme.of(context).brightness == Brightness.light ? 0.25 : 0.35,
+          child: FittedBox(
+            clipBehavior: Clip.hardEdge,
+            fit: BoxFit.cover,
+            child: CachedNetworkImage(
+              imageUrl: _coverPreviewUrl,
+              httpHeaders: {
+                "Authorization": Api.getAuthorizationHeaderValue(account),
+              },
+              filterQuality: FilterQuality.high,
+              errorWidget: (context, url, error) {
+                // just leave it empty
+                return Container();
+              },
+              imageRenderMethodForWeb: ImageRenderMethodForWeb.HttpGet,
+            ),
+          ),
+        );
+      }
+    } catch (_) {}
+
+    return SliverAppBar(
+      floating: true,
+      expandedHeight: 160,
+      flexibleSpace: FlexibleSpaceBar(
+        background: cover,
+        title: Text(
+          album.name,
+          style: TextStyle(
+            color: AppTheme.getPrimaryTextColor(context),
+          ),
+        ),
+      ),
+      actions: [
+        PopupMenuButton(
+          icon: const Icon(Icons.zoom_in),
+          tooltip: AppLocalizations.of(context).zoomTooltip,
+          itemBuilder: (context) => [
+            PopupMenuZoom(
+              initialValue: _thumbZoomLevel,
+              minValue: 0,
+              maxValue: 2,
+              onChanged: (value) {
+                setState(() {
+                  _thumbZoomLevel = value.round();
+                });
+                Pref.inst().setAlbumViewerZoomLevel(_thumbZoomLevel);
+              },
+            ),
+          ],
+        ),
+      ],
+    );
+  }
+
+  Widget buildSelectionAppBar(BuildContext context, List<Widget> actions) {
+    return Theme(
+      data: Theme.of(context).copyWith(
+        appBarTheme: AppTheme.getContextualAppBarTheme(context),
+      ),
+      child: SliverAppBar(
+        pinned: true,
+        leading: IconButton(
+          icon: const Icon(Icons.close),
+          tooltip: MaterialLocalizations.of(context).closeButtonTooltip,
+          onPressed: () {
+            setState(() {
+              clearSelectedItems();
+            });
+          },
+        ),
+        title: Text(AppLocalizations.of(context)
+            .selectionAppBarTitle(selectedListItems.length)),
+        actions: actions,
+      ),
+    );
+  }
+
+  @override
+  get itemStreamListCellSize => thumbSize;
+
+  @protected
+  int get thumbSize {
+    switch (_thumbZoomLevel) {
+      case 1:
+        return 176;
+
+      case 2:
+        return 256;
+
+      case 0:
+      default:
+        return 112;
+    }
+  }
+
+  String _coverPreviewUrl;
+  var _thumbZoomLevel = 0;
+}

lib/widget/dynamic_album_viewer.dart

@@ -0,0 +1,301 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+import 'package:logging/logging.dart';
+import 'package:nc_photos/account.dart';
+import 'package:nc_photos/api/api_util.dart' as api_util;
+import 'package:nc_photos/entity/album.dart';
+import 'package:nc_photos/entity/album/cover_provider.dart';
+import 'package:nc_photos/entity/file.dart';
+import 'package:nc_photos/entity/file/data_source.dart';
+import 'package:nc_photos/entity/file_util.dart' as file_util;
+import 'package:nc_photos/iterable_extension.dart';
+import 'package:nc_photos/k.dart' as k;
+import 'package:nc_photos/list_extension.dart';
+import 'package:nc_photos/snack_bar_manager.dart';
+import 'package:nc_photos/theme.dart';
+import 'package:nc_photos/use_case/populate_album.dart';
+import 'package:nc_photos/use_case/remove.dart';
+import 'package:nc_photos/use_case/update_album.dart';
+import 'package:nc_photos/widget/album_viewer_mixin.dart';
+import 'package:nc_photos/widget/photo_list_item.dart';
+import 'package:nc_photos/widget/selectable_item_stream_list_mixin.dart';
+import 'package:nc_photos/widget/viewer.dart';
+
+class DynamicAlbumViewerArguments {
+  DynamicAlbumViewerArguments(this.account, this.album);
+
+  final Account account;
+  final Album album;
+}
+
+class DynamicAlbumViewer extends StatefulWidget {
+  static const routeName = "/dynamic-album-viewer";
+
+  DynamicAlbumViewer({
+    Key key,
+    @required this.account,
+    @required this.album,
+  }) : super(key: key);
+
+  DynamicAlbumViewer.fromArgs(DynamicAlbumViewerArguments args, {Key key})
+      : this(
+          key: key,
+          account: args.account,
+          album: args.album,
+        );
+
+  @override
+  createState() => _DynamicAlbumViewerState();
+
+  final Account account;
+  final Album album;
+}
+
+class _DynamicAlbumViewerState extends State<DynamicAlbumViewer>
+    with
+        WidgetsBindingObserver,
+        SelectableItemStreamListMixin<DynamicAlbumViewer>,
+        AlbumViewerMixin<DynamicAlbumViewer> {
+  @override
+  initState() {
+    super.initState();
+    _initAlbum();
+  }
+
+  @override
+  build(BuildContext context) {
+    return AppTheme(
+      child: Scaffold(
+        body: Builder(builder: (context) => _buildContent(context)),
+      ),
+    );
+  }
+
+  void _initAlbum() {
+    PopulateAlbum()(widget.account, widget.album).then((items) {
+      if (mounted) {
+        setState(() {
+          _album = widget.album;
+          _transformItems(items);
+          final coverFile = initCover(widget.account, _backingFiles);
+          if (coverFile != null &&
+              _album.coverProvider is AlbumAutoCoverProvider) {
+            // cache the result for later use
+            if (coverFile.path !=
+                (_album.coverProvider as AlbumAutoCoverProvider)
+                    .coverFile
+                    ?.path) {
+              _log.info("[_initAlbum] Updating album cover");
+              _album = _album.copyWith(
+                  coverProvider: AlbumAutoCoverProvider(coverFile: coverFile));
+              UpdateAlbum(AlbumRepo(AlbumCachedDataSource()))(
+                  widget.account, _album);
+            }
+          }
+        });
+      }
+    });
+  }
+
+  Widget _buildContent(BuildContext context) {
+    if (_album == null) {
+      return CustomScrollView(
+        slivers: [
+          buildNormalAppBar(context, widget.account, widget.album),
+          const SliverToBoxAdapter(
+            child: const LinearProgressIndicator(),
+          ),
+        ],
+      );
+    }
+    return buildItemStreamListOuter(
+      context,
+      child: Theme(
+        data: Theme.of(context).copyWith(
+          accentColor: AppTheme.getOverscrollIndicatorColor(context),
+        ),
+        child: CustomScrollView(
+          slivers: [
+            _buildAppBar(context),
+            SliverPadding(
+              padding: const EdgeInsets.all(16),
+              sliver: buildItemStreamList(context),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
+  Widget _buildAppBar(BuildContext context) {
+    if (isSelectionMode) {
+      return buildSelectionAppBar(context, [
+        PopupMenuButton(
+          tooltip: MaterialLocalizations.of(context).moreButtonTooltip,
+          itemBuilder: (context) => [
+            PopupMenuItem(
+              value: _SelectionAppBarOption.delete,
+              child: Text(AppLocalizations.of(context).deleteSelectedTooltip),
+            ),
+          ],
+          onSelected: (option) {
+            if (option == _SelectionAppBarOption.delete) {
+              _onSelectionAppBarDeletePressed();
+            }
+          },
+        ),
+      ]);
+    } else {
+      return buildNormalAppBar(context, widget.account, _album);
+    }
+  }
+
+  void _onItemTap(int index) {
+    Navigator.pushNamed(context, Viewer.routeName,
+        arguments: ViewerArguments(widget.account, _backingFiles, index));
+  }
+
+  void _onSelectionAppBarDeletePressed() async {
+    SnackBarManager().showSnackBar(SnackBar(
+      content: Text(AppLocalizations.of(context)
+          .deleteSelectedProcessingNotification(selectedListItems.length)),
+      duration: k.snackBarDurationShort,
+    ));
+
+    final selectedIndexes =
+        selectedListItems.map((e) => itemStreamListItems.indexOf(e)).toList();
+    final selectedFiles = _backingFiles.takeIndex(selectedIndexes).toList();
+    setState(() {
+      clearSelectedItems();
+    });
+
+    final fileRepo = FileRepo(FileCachedDataSource());
+    final albumRepo = AlbumRepo(AlbumCachedDataSource());
+    final failures = <File>[];
+    for (final f in selectedFiles) {
+      try {
+        await Remove(fileRepo, albumRepo).call(widget.account, f);
+      } catch (e, stacktrace) {
+        _log.shout(
+            "[_onSelectionAppBarDeletePressed] Failed while removing file" +
+                (kDebugMode ? ": ${f.path}" : ""),
+            e,
+            stacktrace);
+        failures.add(f);
+      }
+    }
+
+    if (failures.isEmpty) {
+      SnackBarManager().showSnackBar(SnackBar(
+        content: Text(
+            AppLocalizations.of(context).deleteSelectedSuccessNotification),
+        duration: k.snackBarDurationNormal,
+      ));
+    } else {
+      SnackBarManager().showSnackBar(SnackBar(
+        content: Text(AppLocalizations.of(context)
+            .deleteSelectedFailureNotification(failures.length)),
+        duration: k.snackBarDurationNormal,
+      ));
+    }
+    final successes =
+        selectedFiles.where((element) => !failures.containsIdentical(element));
+    if (successes.isNotEmpty) {
+      setState(() {
+        _backingFiles
+            .removeWhere((element) => successes.containsIdentical(element));
+        _onBackingFilesUpdated();
+      });
+    }
+  }
+
+  void _transformItems(List<AlbumItem> items) {
+    _backingFiles = items
+        .whereType<AlbumFileItem>()
+        .map((e) => e.file)
+        .where((element) => file_util.isSupportedFormat(element))
+        .sorted(compareFileDateTimeDescending);
+    _onBackingFilesUpdated();
+  }
+
+  void _onBackingFilesUpdated() {
+    itemStreamListItems = () sync* {
+      for (int i = 0; i < _backingFiles.length; ++i) {
+        final f = _backingFiles[i];
+
+        final previewUrl = api_util.getFilePreviewUrl(widget.account, f,
+            width: thumbSize, height: thumbSize);
+        if (file_util.isSupportedImageFormat(f)) {
+          yield _ImageListItem(
+            file: f,
+            account: widget.account,
+            previewUrl: previewUrl,
+            onTap: () => _onItemTap(i),
+          );
+        } else if (file_util.isSupportedVideoFormat(f)) {
+          yield _VideoListItem(
+            account: widget.account,
+            previewUrl: previewUrl,
+            onTap: () => _onItemTap(i),
+          );
+        } else {
+          _log.shout(
+              "[_onBackingFilesUpdated] Unsupported file format: ${f.contentType}");
+        }
+      }
+    }();
+  }
+
+  Album _album;
+  var _backingFiles = <File>[];
+
+  static final _log =
+      Logger("widget.dynamic_album_viewer._DynamicAlbumViewerState");
+}
+
+class _ImageListItem extends SelectableItemStreamListItem {
+  _ImageListItem({
+    @required this.file,
+    @required this.account,
+    @required this.previewUrl,
+    VoidCallback onTap,
+  }) : super(onTap: onTap, isSelectable: true);
+
+  @override
+  buildWidget(BuildContext context) {
+    return PhotoListImage(
+      account: account,
+      previewUrl: previewUrl,
+      isGif: file.contentType == "image/gif",
+    );
+  }
+
+  final File file;
+  final Account account;
+  final String previewUrl;
+}
+
+class _VideoListItem extends SelectableItemStreamListItem {
+  _VideoListItem({
+    @required this.account,
+    @required this.previewUrl,
+    VoidCallback onTap,
+  }) : super(onTap: onTap, isSelectable: true);
+
+  @override
+  buildWidget(BuildContext context) {
+    return PhotoListVideo(
+      account: account,
+      previewUrl: previewUrl,
+    );
+  }
+
+  final Account account;
+  final String previewUrl;
+}
+
+enum _SelectionAppBarOption {
+  delete,
+}

lib/widget/home_albums.dart

@@ -25,6 +25,7 @@ import 'package:nc_photos/use_case/remove.dart';
 import 'package:nc_photos/widget/album_grid_item.dart';
 import 'package:nc_photos/widget/album_viewer.dart';
 import 'package:nc_photos/widget/archive_viewer.dart';
+import 'package:nc_photos/widget/dynamic_album_viewer.dart';
 import 'package:nc_photos/widget/home_app_bar.dart';
 import 'package:nc_photos/widget/new_album_dialog.dart';
 import 'package:tuple/tuple.dart';
@@ -180,11 +181,15 @@ class _HomeAlbumsState extends State<HomeAlbums> {
     if (item.album.provider is AlbumStaticProvider) {
       subtitle = AppLocalizations.of(context)
           .albumSize(AlbumStaticProvider.of(item.album).items.length);
+    } else if (item.album.provider is AlbumDirProvider) {
+      subtitle =
+          (item.album.provider as AlbumDirProvider).dirs.first.strippedPath;
     }
     return AlbumGridItem(
       cover: _buildAlbumCover(context, item.album),
       title: item.album.name,
       subtitle: subtitle,
+      isDynamic: item.album.provider is! AlbumStaticProvider,
       isSelected: _selectedItems.contains(item),
       onTap: () => _onItemTap(item),
       onLongPress: _isSelectionMode ? null : () => _onItemLongPress(item),
@@ -306,8 +311,13 @@ class _HomeAlbumsState extends State<HomeAlbums> {
         });
       }
     } else {
-      Navigator.of(context).pushNamed(AlbumViewer.routeName,
-          arguments: AlbumViewerArguments(widget.account, item.album));
+      if (item.album.provider is AlbumStaticProvider) {
+        Navigator.of(context).pushNamed(AlbumViewer.routeName,
+            arguments: AlbumViewerArguments(widget.account, item.album));
+      } else {
+        Navigator.of(context).pushNamed(DynamicAlbumViewer.routeName,
+            arguments: DynamicAlbumViewerArguments(widget.account, item.album));
+      }
     }
   }
 

lib/widget/my_app.dart

@@ -10,6 +10,7 @@ import 'package:nc_photos/theme.dart';
 import 'package:nc_photos/widget/album_viewer.dart';
 import 'package:nc_photos/widget/archive_viewer.dart';
 import 'package:nc_photos/widget/connect.dart';
+import 'package:nc_photos/widget/dynamic_album_viewer.dart';
 import 'package:nc_photos/widget/home.dart';
 import 'package:nc_photos/widget/root_picker.dart';
 import 'package:nc_photos/widget/settings.dart';
@@ -90,6 +91,7 @@ class _MyAppState extends State<MyApp> implements SnackBarHandler {
     route ??= _handleAlbumViewerRoute(settings);
     route ??= _handleSettingsRoute(settings);
     route ??= _handleArchiveViewerRoute(settings);
+    route ??= _handleDynamicAlbumViewerRoute(settings);
     return route;
   }
 
@@ -212,6 +214,22 @@ class _MyAppState extends State<MyApp> implements SnackBarHandler {
     return null;
   }
 
+  Route<dynamic> _handleDynamicAlbumViewerRoute(RouteSettings settings) {
+    try {
+      if (settings.name == DynamicAlbumViewer.routeName &&
+          settings.arguments != null) {
+        final DynamicAlbumViewerArguments args = settings.arguments;
+        return MaterialPageRoute(
+          builder: (context) => DynamicAlbumViewer.fromArgs(args),
+        );
+      }
+    } catch (e) {
+      _log.severe(
+          "[_handleDynamicAlbumViewerRoute] Failed while handling route", e);
+    }
+    return null;
+  }
+
   final _scaffoldMessengerKey = GlobalKey<ScaffoldMessengerState>();
 
   AppEventListener<ThemeChangedEvent> _themeChangedListener;