zoomable gallery view

add network permission

android/app/src/main/AndroidManifest.xml

@@ -2,6 +2,7 @@
     package="eu.heili.gallery">
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+    <uses-permission android:name="android.permission.INTERNET"/>
    <application
         android:label="gallery"
         android:name="${applicationName}"

lib/full_screen_image_view.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:photo_view/photo_view_gallery.dart';
 
 import 'data_provider/data_provider.dart';
 import 'package:photo_view/photo_view.dart';
@@ -41,21 +42,31 @@ class _FullScreenImageViewState extends State<FullScreenImageView> {
           },
           child: Focus(
             autofocus: true,
-            child: PageView.builder(
+            child: PhotoViewGallery.builder(
+              scrollPhysics: const BouncingScrollPhysics(),
+              builder: (BuildContext context, int index) {
+                return PhotoViewGalleryPageOptions(
+                  imageProvider: widget.provider.getImageProvider(widget.items[index].uri),
+                  initialScale: PhotoViewComputedScale.contained,
+                  minScale: PhotoViewComputedScale.contained,
+                  heroAttributes: PhotoViewHeroAttributes(tag: widget.items[index].name),
+                );
+              },
                 itemCount: widget.items.length,
-                controller: _controller,
-                pageSnapping: true,
-                itemBuilder: (context, pagePosition) {
-                  return Container(
-                    margin: const EdgeInsets.all(10),
-                    child: PhotoView(
-                      backgroundDecoration:
-                          const BoxDecoration(color: Colors.white),
-                      imageProvider: widget.provider
-                          .getImageProvider(widget.items[pagePosition].uri),
-                    ),
-                  );
-                }),
+              loadingBuilder: (context, event) => Center(
+                child: SizedBox(
+                  width: 20.0,
+                  height: 20.0,
+                  child: CircularProgressIndicator(
+                    value: event == null || event.expectedTotalBytes == null
+                        ? null
+                        : event.cumulativeBytesLoaded / event.expectedTotalBytes!,
+                  ),
+                ),
+              ),
+              backgroundDecoration: const BoxDecoration(color: Colors.white),
+              pageController: _controller,
+            ),
           ),
         ),
       ),

lib/image_grid.dart

@@ -106,7 +106,7 @@ class _ImageGridState extends State<ImageGrid> {
               },
             );
           } else if (snapshot.hasError) {
-            return const Text("Error loading files");
+            return Text("Error loading files: ${snapshot.error}");
           }
         }