Refactor: move constants up

Signed-off-by: Neeraj Gupta <254676+ua741@users.noreply.github.com>

lib/ui/collections/device/vertical_grid_view.dart

@@ -0,0 +1,94 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:logging/logging.dart';
+import 'package:photos/core/event_bus.dart';
+import 'package:photos/db/device_files_db.dart';
+import 'package:photos/db/files_db.dart';
+import 'package:photos/events/backup_folders_updated_event.dart';
+import 'package:photos/events/local_photos_updated_event.dart';
+import "package:photos/generated/l10n.dart";
+import 'package:photos/models/device_collection.dart';
+import "package:photos/ui/collections/device/device_folder_item.dart";
+import 'package:photos/ui/common/loading_widget.dart';
+import 'package:photos/ui/viewer/gallery/empty_state.dart';
+
+class DeviceFoldersGridView extends StatefulWidget {
+  const DeviceFoldersGridView({
+    Key? key,
+  }) : super(key: key);
+
+  @override
+  State<DeviceFoldersGridView> createState() => _DeviceFoldersGridViewState();
+}
+
+class _DeviceFoldersGridViewState extends State<DeviceFoldersGridView> {
+  StreamSubscription<BackupFoldersUpdatedEvent>? _backupFoldersUpdatedEvent;
+  StreamSubscription<LocalPhotosUpdatedEvent>? _localFilesSubscription;
+  String _loadReason = "init";
+
+  @override
+  void initState() {
+    _backupFoldersUpdatedEvent =
+        Bus.instance.on<BackupFoldersUpdatedEvent>().listen((event) {
+      _loadReason = event.reason;
+      if (mounted) {
+        setState(() {});
+      }
+    });
+    _localFilesSubscription =
+        Bus.instance.on<LocalPhotosUpdatedEvent>().listen((event) {
+      _loadReason = event.reason;
+      setState(() {});
+    });
+    super.initState();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    debugPrint("${(DeviceFoldersGridView).toString()} - $_loadReason");
+    final logger = Logger((_DeviceFoldersGridViewState).toString());
+    return SizedBox(
+      height: 170,
+      child: Align(
+        alignment: Alignment.centerLeft,
+        child: FutureBuilder<List<DeviceCollection>>(
+          future: FilesDB.instance
+              .getDeviceCollections(includeCoverThumbnail: true),
+          builder: (context, snapshot) {
+            if (snapshot.hasData) {
+              return snapshot.data!.isEmpty
+                  ? const Padding(
+                      padding: EdgeInsets.all(22),
+                      child: EmptyState(),
+                    )
+                  : ListView.builder(
+                      scrollDirection: Axis.horizontal,
+                      padding: const EdgeInsets.fromLTRB(8, 0, 8, 0),
+                      physics: const ScrollPhysics(),
+                      // to disable GridView's scrolling
+                      itemBuilder: (context, index) {
+                        final deviceCollection = snapshot.data![index];
+                        return DeviceFolderItem(deviceCollection);
+                      },
+                      itemCount: snapshot.data!.length,
+                    );
+            } else if (snapshot.hasError) {
+              logger.severe("failed to load device gallery", snapshot.error);
+              return Text(S.of(context).failedToLoadAlbums);
+            } else {
+              return const EnteLoadingWidget();
+            }
+          },
+        ),
+      ),
+    );
+  }
+
+  @override
+  void dispose() {
+    _backupFoldersUpdatedEvent?.cancel();
+    _localFilesSubscription?.cancel();
+    super.dispose();
+  }
+}

lib/ui/collections/vertical_grid_view.dart

@@ -7,10 +7,12 @@ import "package:photos/ui/collections/album/row_item.dart";
 class CollectionVerticalGridView extends StatelessWidget {
   final List<Collection>? collections;
   final Widget? appTitle;
-  final double gapBetweenAlbums = 0.0;
   static const maxThumbnailWidth = 160.0;
+
   // This includes the name, count and padding below the thumbnail
   static const albumBottomInfoHeight = 21.0;
+  static const double horizontalPadding = 20;
+  static const double gapBetweenAlbumsInRow = 16.0;
 
   const CollectionVerticalGridView(
     this.collections, {
@@ -34,10 +36,8 @@ class CollectionVerticalGridView extends StatelessWidget {
   Widget _getBody(BuildContext context) {
     final double screenWidth = MediaQuery.of(context).size.width;
 
-    const double horizontalPadding = 20;
     final int albumsCountInOneRow =
         max(screenWidth ~/ (maxThumbnailWidth + horizontalPadding), 2);
-    const double gapBetweenAlbumsInRow = 16.0;
 
     return SafeArea(
       child: Padding(