Add some amount of caching

lib/core/lru_map.dart

@@ -1,7 +1,7 @@
 import 'dart:collection';
 import 'dart:typed_data';
 
-import 'package:photo_manager/photo_manager.dart';
+import 'package:flutter/material.dart';
 
 typedef EvictionHandler<K, V>(K key, V value);
 
@@ -38,31 +38,31 @@ class LRUMap<K, V> {
 }
 
 class ImageLruCache {
-  static LRUMap<_ImageCacheEntity, Uint8List> _map = LRUMap(500);
+  static LRUMap<_ImageCacheEntity, Image> _map = LRUMap(500);
 
-  static Uint8List getData(AssetEntity entity, [int size = 64]) {
-    return _map.get(_ImageCacheEntity(entity, size));
+  static Image getData(String path, [int size = 64]) {
+    return _map.get(_ImageCacheEntity(path, size));
   }
 
-  static void setData(AssetEntity entity, int size, Uint8List list) {
-    _map.put(_ImageCacheEntity(entity, size), list);
+  static void setData(String path, int size, Image image) {
+    _map.put(_ImageCacheEntity(path, size), image);
   }
 }
 
 class _ImageCacheEntity {
-  AssetEntity entity;
+  String path;
   int size;
 
-  _ImageCacheEntity(this.entity, this.size);
+  _ImageCacheEntity(this.path, this.size);
 
   @override
   bool operator ==(Object other) =>
       identical(this, other) ||
       other is _ImageCacheEntity &&
           runtimeType == other.runtimeType &&
-          entity == other.entity &&
+          path == other.path &&
           size == other.size;
 
   @override
-  int get hashCode => entity.hashCode ^ size.hashCode;
+  int get hashCode => path.hashCode ^ size.hashCode;
 }

lib/main.dart

@@ -1,4 +1,3 @@
-import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:logger/logger.dart';
@@ -6,7 +5,7 @@ import 'package:myapp/models/photo.dart';
 import 'package:myapp/photo_loader.dart';
 import 'package:myapp/photo_provider.dart';
 import 'package:myapp/photo_sync_manager.dart';
-import 'package:myapp/ui/detail_page.dart';
+import 'package:myapp/ui/gallery.dart';
 import 'package:myapp/ui/loading_widget.dart';
 import 'package:provider/provider.dart';
 import 'package:myapp/ui/gallery_page.dart';
@@ -19,7 +18,7 @@ void main() async {
   await provider.refreshGalleryList();
   var assets = await provider.list[0].assetList;
   var photoSyncManager = PhotoSyncManager(assets);
-  await photoSyncManager.init();
+  photoSyncManager.init();
   runApp(MyApp2());
 }
 
@@ -50,55 +49,24 @@ class MyApp2 extends StatelessWidget {
         builder: (context, snapshot) {
           Widget body;
           if (snapshot.hasData) {
-            body = ChangeNotifierProvider<PhotoLoader>.value(
-                value: photoLoader,
-                child: GridView.builder(
-                  itemBuilder: _buildItem,
-                  itemCount: snapshot.data.length,
-                  gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
-                      crossAxisCount: 4),
-                ));
+            body = Gallery();
           } else if (snapshot.hasError) {
             body = Text("Error!");
           } else {
             body = loadWidget;
           }
-          return MaterialApp(
-            title: title,
-            theme: ThemeData.dark(),
-            home: Scaffold(
-                appBar: AppBar(
-                  title: Text(title),
-                ),
-                body: body),
+          return ChangeNotifierProvider<PhotoLoader>.value(
+            value: photoLoader,
+            child: MaterialApp(
+              title: title,
+              theme: ThemeData.dark(),
+              home: Scaffold(
+                  appBar: AppBar(
+                    title: Text(title),
+                  ),
+                  body: body),
+            ),
           );
         });
   }
-
-  Widget _buildItem(BuildContext context, int index) {
-    logger.i("Building item");
-    var file = File(photoLoader.getPhotos()[index].localPath);
-    return GestureDetector(
-      onTap: () async {
-        routeToDetailPage(file, context);
-      },
-      child: Hero(
-        child: Image.file(file),
-        tag: 'photo_' + file.path,
-      ),
-    );
-  }
-
-  void routeToDetailPage(File file, BuildContext context) async {
-    final page = DetailPage(
-      file: file,
-    );
-    Navigator.of(context).push(
-      MaterialPageRoute(
-        builder: (BuildContext context) {
-          return page;
-        },
-      ),
-    );
-  }
 }

lib/photo_loader.dart

@@ -1,11 +1,15 @@
+import 'dart:typed_data';
+
 import 'package:flutter/material.dart';
 import 'package:logger/logger.dart';
 import 'package:myapp/db/db_helper.dart';
 import 'package:myapp/models/photo.dart';
+import 'package:photo_manager/photo_manager.dart';
 
 class PhotoLoader extends ChangeNotifier {
   final logger = Logger();
-  List<Photo> _photos;
+  final _photos = List<Photo>();
+  final _assetMap = Map<String, AssetEntity>();
   
   PhotoLoader._privateConstructor();
   static final PhotoLoader instance = PhotoLoader._privateConstructor();
@@ -16,7 +20,9 @@ class PhotoLoader extends ChangeNotifier {
 
   Future<List<Photo>> loadPhotos() async {
     DatabaseHelper db = DatabaseHelper.instance;
-    _photos = await db.getAllPhotos();
+    var photos = await db.getAllPhotos();
+    _photos.clear();
+    _photos.addAll(photos);
     logger.i("Imported photo size: " + _photos.length.toString());
     return _photos;
   }
@@ -26,4 +32,16 @@ class PhotoLoader extends ChangeNotifier {
     logger.i("Reloading...");
     notifyListeners();
   }
+
+  void addAsset(String path, AssetEntity asset) {
+    _assetMap[path] = asset;
+  }
+
+  Future<Uint8List> getThumbnail(String path, int size) {
+    if (!_assetMap.containsKey(path)) {
+      logger.w("No thumbnail");
+      return Future.value(null);
+    }
+    return _assetMap[path].thumbDataWithSize(size, size);
+  }
 }

lib/photo_sync_manager.dart

@@ -1,3 +1,5 @@
+import 'dart:typed_data';
+
 import 'package:logger/logger.dart';
 import 'package:myapp/db/db_helper.dart';
 import 'package:myapp/photo_loader.dart';
@@ -39,6 +41,7 @@ class PhotoSyncManager {
       if (asset.createDateTime.millisecondsSinceEpoch > lastDBUpdateTimestamp) {
         await DatabaseHelper.instance.insertPhoto(await Photo.fromAsset(asset));
       }
+      PhotoLoader.instance.addAsset((await asset.originFile).path, asset);
     }
     return await prefs.setInt(
         _lastDBUpdateTimestampKey, DateTime.now().millisecondsSinceEpoch);

lib/ui/detail_page.dart

@@ -1,6 +1,7 @@
 import 'dart:io';
 
 import 'package:flutter/material.dart';
+import 'package:myapp/core/lru_map.dart';
 
 class DetailPage extends StatefulWidget {
   final File file;
@@ -30,10 +31,12 @@ class _DetailPageState extends State<DetailPage> {
       },
       child: Hero(
         tag: 'photo_' + widget.file.path,
-        child: Image.file(
-          widget.file,
-          filterQuality: FilterQuality.low,
-        ),
+        child: ImageLruCache.getData(widget.file.path) == null
+            ? Image.file(
+                widget.file,
+                filterQuality: FilterQuality.low,
+              )
+            : ImageLruCache.getData(widget.file.path),
       ),
     );
   }

lib/ui/gallery.dart

@@ -0,0 +1,68 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:logger/logger.dart';
+import 'package:myapp/photo_loader.dart';
+import 'package:myapp/ui/image_widget.dart';
+import 'package:provider/provider.dart';
+
+import 'change_notifier_builder.dart';
+import 'detail_page.dart';
+
+class Gallery extends StatefulWidget {
+  @override
+  _GalleryState createState() {
+    return _GalleryState();
+  }
+}
+
+class _GalleryState extends State<Gallery> {
+  Logger _logger = Logger();
+  
+  PhotoLoader get photoLoader => Provider.of<PhotoLoader>(context);
+  
+  @override
+  Widget build(BuildContext context) {
+    _logger.i("Build");
+    return ChangeNotifierBuilder(
+      value: photoLoader,
+      builder: (_, __) {
+        return GridView.builder(
+          itemBuilder: _buildItem,
+          itemCount: photoLoader.getPhotos().length,
+          gridDelegate:
+              SliverGridDelegateWithFixedCrossAxisCount(crossAxisCount: 4),
+        );
+      },
+    );
+  }
+
+  Widget _buildItem(BuildContext context, int index) {
+    var file = File(photoLoader.getPhotos()[index].localPath);
+    return GestureDetector(
+      onTap: () async {
+        routeToDetailPage(file, context);
+      },
+      child: Hero(
+        child: Padding(
+          padding: const EdgeInsets.all(1.0),
+          child: ImageWidget(path: file.path),
+        ),
+        tag: 'photo_' + file.path,
+      ),
+    );
+  }
+
+  void routeToDetailPage(File file, BuildContext context) async {
+    final page = DetailPage(
+      file: file,
+    );
+    Navigator.of(context).push(
+      MaterialPageRoute(
+        builder: (BuildContext context) {
+          return page;
+        },
+      ),
+    );
+  }
+}

lib/ui/gallery_page.dart

@@ -1,9 +1,9 @@
 import 'package:flutter/material.dart';
 import 'package:myapp/photo_provider.dart';
+import 'package:myapp/ui/image_widget.dart';
 import 'package:photo_manager/photo_manager.dart';
 import 'package:myapp/ui/change_notifier_builder.dart';
 import 'package:myapp/ui/loading_widget.dart';
-import 'package:myapp/ui/image_item_widget.dart';
 import 'package:myapp/ui/detail_page.dart';
 import 'package:provider/provider.dart';
 
@@ -80,9 +80,9 @@ class _GalleryPageState extends State<GalleryPage> {
       onTap: () async {
         routeToDetailPage(entity);
       },
-      child: ImageItemWidget(
+      child: ImageWidget(
         key: ValueKey(entity),
-        entity: entity,
+        path: "",
       ),
     );
   }

lib/ui/image_item_widget.dart

@@ -1,73 +0,0 @@
-import 'dart:typed_data';
-
-import 'package:flutter/material.dart';
-import 'package:myapp/core/lru_map.dart';
-import 'package:myapp/ui/loading_widget.dart';
-import 'package:photo_manager/photo_manager.dart';
-
-class ImageItemWidget extends StatefulWidget {
-  final AssetEntity entity;
-
-  const ImageItemWidget({
-    Key key,
-    this.entity,
-  }) : super(key: key);
-  @override
-  _ImageItemWidgetState createState() => _ImageItemWidgetState();
-}
-
-class _ImageItemWidgetState extends State<ImageItemWidget> {
-  @override
-  Widget build(BuildContext context) {
-    final item = widget.entity;
-    final size = 130;
-    final u8List = ImageLruCache.getData(item, size);
-
-    Widget image;
-
-    if (u8List != null) {
-      return _buildImageWidget(item, u8List, size);
-    } else {
-      image = FutureBuilder<Uint8List>(
-        future: item.thumbDataWithSize(size, size),
-        builder: (context, snapshot) {
-          Widget w;
-          if (snapshot.hasError) {
-            w = Center(
-              child: Text("load error, error: ${snapshot.error}"),
-            );
-          }
-          if (snapshot.hasData) {
-            ImageLruCache.setData(item, size, snapshot.data);
-            w = _buildImageWidget(item, snapshot.data, size);
-          } else {
-            w = Center(
-              child: loadWidget,
-            );
-          }
-
-          return w;
-        },
-      );
-    }
-
-    return image;
-  }
-
-  Widget _buildImageWidget(AssetEntity entity, Uint8List uint8list, num size) {
-    return Image.memory(
-      uint8list,
-      width: size.toDouble(),
-      height: size.toDouble(),
-      fit: BoxFit.cover,
-    );
-  }
-
-  @override
-  void didUpdateWidget(ImageItemWidget oldWidget) {
-    super.didUpdateWidget(oldWidget);
-    if (widget.entity.id != oldWidget.entity.id) {
-      setState(() {});
-    }
-  }
-}

lib/ui/image_widget.dart

@@ -0,0 +1,78 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:logger/logger.dart';
+import 'package:myapp/core/lru_map.dart';
+import 'package:myapp/photo_loader.dart';
+import 'package:myapp/ui/loading_widget.dart';
+import 'package:provider/provider.dart';
+
+class ImageWidget extends StatefulWidget {
+  final String path;
+
+  const ImageWidget({
+    Key key,
+    this.path,
+  }) : super(key: key);
+  @override
+  _ImageWidgetState createState() => _ImageWidgetState();
+}
+
+class _ImageWidgetState extends State<ImageWidget> {
+  var _logger = Logger();
+  PhotoLoader get photoLoader => Provider.of<PhotoLoader>(context);
+
+  @override
+  Widget build(BuildContext context) {
+    final path = widget.path;
+    final size = 124;
+    final cachedImage = ImageLruCache.getData(path, size);
+
+    Widget image;
+
+    if (cachedImage != null) {
+      _logger.i("Cache hit for " + path);
+      image = cachedImage;
+    } else {
+      image = FutureBuilder<Image>(
+        future: _buildImageWidget(path, size),
+        builder: (context, snapshot) {
+          if (snapshot.hasData) {
+            ImageLruCache.setData(path, size, snapshot.data);
+            return snapshot.data;
+          } else {
+            return loadWidget;
+          }
+        },
+      );
+    }
+
+    return image;
+  }
+
+  Future<Image> _buildImageWidget(String path, num size) async {
+    var thumbnail = await photoLoader.getThumbnail(path, size);
+    if (thumbnail != null) {
+      return Image.memory(
+        thumbnail,
+        width: size.toDouble(),
+        height: size.toDouble(),
+        fit: BoxFit.cover,
+      );
+    } else {
+      return Image.file(
+          File(path),
+          width: size.toDouble(),
+          height: size.toDouble(),
+          fit: BoxFit.cover);
+    }
+  }
+
+  @override
+  void didUpdateWidget(ImageWidget oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.path != oldWidget.path) {
+      setState(() {});
+    }
+  }
+}