info: back to image on top overscroll or button

lib/widgets/fullscreen/image_page.dart

@@ -73,8 +73,20 @@ class FullscreenPageState extends State<FullscreenPage> with SingleTickerProvide
                 onPageChanged: (page) => setState(() => _currentHorizontalPage = page),
                 onScaleChanged: (state) => setState(() => _isInitialScale = state == PhotoViewScaleState.initial),
               ),
-              InfoPage(
+              NotificationListener(
-                entry: entries[_currentHorizontalPage],
+                onNotification: (notification) {
+                  if (notification is BackUpNotification) {
+                    _verticalPager.animateToPage(
+                      0,
+                      duration: const Duration(milliseconds: 400),
+                      curve: Curves.easeInOut,
+                    );
+                  }
+                  return false;
+                },
+                child: InfoPage(
+                  entry: entries[_currentHorizontalPage],
+                ),
               ),
             ],
           ),

lib/widgets/fullscreen/info_page.dart

@@ -15,6 +15,7 @@ class InfoPage extends StatefulWidget {
 
 class InfoPageState extends State<InfoPage> {
   Future<Map> _metadataLoader;
+  bool _scrollStartFromTop = false;
 
   ImageEntry get entry => widget.entry;
 
@@ -39,50 +40,74 @@ class InfoPageState extends State<InfoPage> {
     final date = entry.getBestDate();
     return Scaffold(
       appBar: AppBar(
+        leading: IconButton(
+          icon: Icon(Icons.arrow_upward),
+          onPressed: () => BackUpNotification().dispatch(context),
+          tooltip: 'Back to image',
+        ),
         title: Text('Info'),
       ),
-      body: ListView(
+      body: NotificationListener(
-        padding: EdgeInsets.all(8.0),
+        onNotification: (notification) {
-        children: [
+          if (notification is ScrollNotification) {
-          SectionRow('File'),
+            if (notification is ScrollStartNotification) {
-          InfoRow('Title', entry.title),
+              final metrics = notification.metrics;
-          InfoRow('Date', '${DateFormat.yMMMd().format(date)} – ${DateFormat.Hm().format(date)}'),
+              _scrollStartFromTop = metrics.pixels == metrics.minScrollExtent;
-          InfoRow('Resolution', '${entry.width} × ${entry.height} (${entry.getMegaPixels()} MP)'),
+            }
-          InfoRow('Size', formatFilesize(entry.sizeBytes)),
+            if (_scrollStartFromTop) {
-          InfoRow('Path', entry.path),
+              if (notification is ScrollEndNotification) {
-          SectionRow('Location'),
+                _scrollStartFromTop = false;
-          SectionRow('XMP Tags'),
+              } else if (notification is OverscrollNotification) {
-          SectionRow('Metadata'),
+                if (notification.overscroll < 0) {
-          FutureBuilder(
+                  BackUpNotification().dispatch(context);
-            future: _metadataLoader,
+                  _scrollStartFromTop = false;
-            builder: (futureContext, AsyncSnapshot<Map> snapshot) {
+                }
-              if (snapshot.hasError) {
-                return Text(snapshot.error);
               }
-              if (snapshot.connectionState != ConnectionState.done) {
+            }
-                return CircularProgressIndicator();
+          }
-              }
+          return false;
-              final metadataMap = snapshot.data.cast<String, Map>();
+        },
-              final directoryNames = metadataMap.keys.toList()..sort();
+        child: ListView(
-              return Column(
+          padding: EdgeInsets.all(8.0),
-                  crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
-                  children: directoryNames.expand(
+            SectionRow('File'),
-                    (directoryName) {
+            InfoRow('Title', entry.title),
-                      final directory = metadataMap[directoryName];
+            InfoRow('Date', '${DateFormat.yMMMd().format(date)} – ${DateFormat.Hm().format(date)}'),
-                      final tagKeys = directory.keys.toList()..sort();
+            InfoRow('Resolution', '${entry.width} × ${entry.height} (${entry.getMegaPixels()} MP)'),
-                      return [
+            InfoRow('Size', formatFilesize(entry.sizeBytes)),
-                        Padding(
+            InfoRow('Path', entry.path),
-                          padding: EdgeInsets.symmetric(vertical: 4.0),
+            SectionRow('Metadata'),
-                          child: Text(directoryName, style: TextStyle(fontSize: 18)),
+            FutureBuilder(
-                        ),
+              future: _metadataLoader,
-                        ...tagKeys.map((tagKey) => InfoRow(tagKey, directory[tagKey])),
+              builder: (futureContext, AsyncSnapshot<Map> snapshot) {
-                        SizedBox(height: 16),
+                if (snapshot.hasError) {
-                      ];
+                  return Text(snapshot.error);
-                    },
+                }
-                  ).toList());
+                if (snapshot.connectionState != ConnectionState.done) {
-            },
+                  return CircularProgressIndicator();
-          ),
+                }
-        ],
+                final metadataMap = snapshot.data.cast<String, Map>();
+                final directoryNames = metadataMap.keys.toList()..sort();
+                return Column(
+                    crossAxisAlignment: CrossAxisAlignment.start,
+                    children: directoryNames.expand(
+                      (directoryName) {
+                        final directory = metadataMap[directoryName];
+                        final tagKeys = directory.keys.toList()..sort();
+                        return [
+                          Padding(
+                            padding: EdgeInsets.symmetric(vertical: 4.0),
+                            child: Text(directoryName, style: TextStyle(fontSize: 18)),
+                          ),
+                          ...tagKeys.map((tagKey) => InfoRow(tagKey, directory[tagKey])),
+                          SizedBox(height: 16),
+                        ];
+                      },
+                    ).toList());
+              },
+            ),
+          ],
+        ),
       ),
     );
   }
@@ -96,7 +121,7 @@ class SectionRow extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return Padding(
-      padding: EdgeInsets.symmetric(vertical: 4.0),
+      padding: EdgeInsets.symmetric(vertical: 8.0),
       child: Row(
         children: [
           Expanded(child: Divider(color: Colors.white70)),
@@ -131,3 +156,5 @@ class InfoRow extends StatelessWidget {
     );
   }
 }
+
+class BackUpNotification extends Notification {}

lib/widgets/fullscreen/overlay.dart

@@ -2,8 +2,8 @@ import 'dart:math';
 import 'dart:ui';
 
 import 'package:aves/model/android_app_service.dart';
-import 'package:aves/model/metadata_service.dart';
 import 'package:aves/model/image_entry.dart';
+import 'package:aves/model/metadata_service.dart';
 import 'package:flutter/material.dart';
 import 'package:intl/intl.dart';
 
@@ -43,7 +43,11 @@ class FullscreenTopOverlay extends StatelessWidget {
             title: Text('${index + 1}/${entries.length}'),
             actions: [
 //                IconButton(icon: Icon(Icons.delete), onPressed: delete),
-              IconButton(icon: Icon(Icons.share), onPressed: share),
+              IconButton(
+                icon: Icon(Icons.share),
+                onPressed: share,
+                tooltip: 'Share',
+              ),
             ],
             elevation: 0,
             backgroundColor: kOverlayBackground,