Add loading state for first time load

lib/photo_sync_manager.dart

@@ -58,6 +58,11 @@ class PhotoSyncManager {
     return _existingSync;
   }
 
+  Future<bool> hasScannedDisk() async {
+    final prefs = await SharedPreferences.getInstance();
+    return prefs.containsKey(_lastDBUpdateTimestampKey);
+  }
+
   Future<void> _doSync() async {
     final prefs = await SharedPreferences.getInstance();
     final syncStartTimestamp = DateTime.now().microsecondsSinceEpoch;

lib/ui/home_widget.dart

@@ -13,6 +13,7 @@ import 'package:photos/photo_sync_manager.dart';
 import 'package:photos/ui/device_folders_gallery_widget.dart';
 import 'package:photos/ui/gallery.dart';
 import 'package:photos/ui/gallery_app_bar_widget.dart';
+import 'package:photos/ui/loading_photos_widget.dart';
 import 'package:photos/ui/loading_widget.dart';
 import 'package:photos/ui/remote_folder_gallery_widget.dart';
 import 'package:photos/ui/search_page.dart';
@@ -32,11 +33,14 @@ class HomeWidget extends StatefulWidget {
 class _HomeWidgetState extends State<HomeWidget> {
   static final importantItemsFilter = ImportantItemsFilter();
   final _logger = Logger("HomeWidgetState");
+  final _remoteFolderGalleryWidget = RemoteFolderGalleryWidget();
+  final _deviceFolderGalleryWidget = DeviceFolderGalleryWidget();
+
   ShakeDetector _detector;
   int _selectedNavBarItem = 0;
   Set<Photo> _selectedPhotos = HashSet<Photo>();
-  final _deviceFolderGalleryWidget = DeviceFolderGalleryWidget();
-  final _remoteFolderGalleryWidget = RemoteFolderGalleryWidget();
+  StreamSubscription<LocalPhotosUpdatedEvent>
+      _localPhotosUpdatedEventSubscription;
 
   @override
   void initState() {
@@ -46,6 +50,10 @@ class _HomeWidgetState extends State<HomeWidget> {
           _logger.info("Emailing logs");
           LoggingUtil.instance.emailLogs();
         });
+    _localPhotosUpdatedEventSubscription =
+        Bus.instance.on<LocalPhotosUpdatedEvent>().listen((event) {
+      setState(() {});
+    });
     super.initState();
   }
 
@@ -61,19 +69,19 @@ class _HomeWidgetState extends State<HomeWidget> {
       ),
       bottomNavigationBar: _buildBottomNavigationBar(),
       body: FutureBuilder<bool>(
-        future: PhotoRepository.instance.loadPhotos(),
+        future: PhotoSyncManager.instance.hasScannedDisk(),
         builder: (context, snapshot) {
           if (snapshot.hasData) {
             return IndexedStack(
               children: <Widget>[
-                _getMainGalleryWidget(),
+                snapshot.data ? _getMainGalleryWidget() : LoadingPhotosWidget(),
                 _deviceFolderGalleryWidget,
                 _remoteFolderGalleryWidget,
               ],
               index: _selectedNavBarItem,
             );
           } else if (snapshot.hasError) {
-            return Text("Error!");
+            return Center(child: Text(snapshot.error.toString()));
           } else {
             return loadWidget;
           }
@@ -100,19 +108,31 @@ class _HomeWidgetState extends State<HomeWidget> {
     );
   }
 
-  Gallery _getMainGalleryWidget() {
-    return Gallery(
-      () => Future.value(_getFilteredPhotos(PhotoRepository.instance.photos)),
-      selectedPhotos: _selectedPhotos,
-      photoSelectionChangeCallback: (Set<Photo> selectedPhotos) {
-        setState(() {
-          _selectedPhotos = selectedPhotos;
-        });
+  Widget _getMainGalleryWidget() {
+    return FutureBuilder<bool>(
+      future: PhotoRepository.instance.loadPhotos(),
+      builder: (context, snapshot) {
+        if (snapshot.hasData) {
+          return Gallery(
+            () => Future.value(
+                _getFilteredPhotos(PhotoRepository.instance.photos)),
+            selectedPhotos: _selectedPhotos,
+            photoSelectionChangeCallback: (Set<Photo> selectedPhotos) {
+              setState(() {
+                _selectedPhotos = selectedPhotos;
+              });
+            },
+            syncFunction: () {
+              return PhotoSyncManager.instance.sync();
+            },
+            reloadTrigger: Bus.instance.on<LocalPhotosUpdatedEvent>(),
+          );
+        } else if (snapshot.hasError) {
+          return Center(child: Text(snapshot.error.toString()));
+        } else {
+          return loadWidget;
+        }
       },
-      syncFunction: () {
-        return PhotoSyncManager.instance.sync();
-      },
-      reloadTrigger: Bus.instance.on<LocalPhotosUpdatedEvent>(),
     );
   }
 
@@ -161,6 +181,7 @@ class _HomeWidgetState extends State<HomeWidget> {
   @override
   void dispose() {
     _detector.stopListening();
+    _localPhotosUpdatedEventSubscription.cancel();
     super.dispose();
   }
 }

lib/ui/loading_photos_widget.dart

@@ -0,0 +1,26 @@
+import 'package:flutter/material.dart';
+import 'package:photos/ui/loading_widget.dart';
+
+class LoadingPhotosWidget extends StatefulWidget {
+  @override
+  _LoadingPhotosWidgetState createState() => _LoadingPhotosWidgetState();
+}
+
+class _LoadingPhotosWidgetState extends State<LoadingPhotosWidget> {
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        crossAxisAlignment: CrossAxisAlignment.center,
+        children: [
+          loadWidget,
+          Padding(padding: EdgeInsets.all(16)),
+          Text(
+            "Hang on tight, your photos will appear in a jiffy! 🐣",
+          )
+        ],
+      ),
+    );
+  }
+}