fullscreen: swipe down to pop

lib/widgets/album/thumbnail_collection.dart

@@ -147,14 +147,15 @@ class SectionSliver extends StatelessWidget {
     );
   }
 
-  Future _showFullscreen(BuildContext context, ImageEntry entry) {
-    return Navigator.push(
+  _showFullscreen(BuildContext context, ImageEntry entry) {
+    Navigator.push(
       context,
       MaterialPageRoute(
         builder: (context) => FullscreenPage(
           collection: collection,
           initialUri: entry.uri,
         ),
+        fullscreenDialog: true,
       ),
     );
   }

lib/widgets/fullscreen/fullscreen_page.dart

@@ -28,41 +28,9 @@ class FullscreenPage extends AnimatedWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Scaffold(
-      backgroundColor: Colors.black,
-      body: FullscreenBody(
+    return FullscreenBody(
       collection: collection,
       initialUri: initialUri,
-      ),
-      resizeToAvoidBottomInset: false,
-//        Hero(
-//          tag: uri,
-//          child: Stack(
-//            children: [
-//              Center(
-//                child: widget.thumbnail == null
-//                    ? CircularProgressIndicator()
-//                    : Image.memory(
-//                        widget.thumbnail,
-//                        width: requestWidth,
-//                        height: requestHeight,
-//                        fit: BoxFit.contain,
-//                      ),
-//              ),
-//              Center(
-//                child: FadeInImage(
-//                  placeholder: MemoryImage(kTransparentImage),
-//                  image: FileImage(File(path)),
-//                  fadeOutDuration: Duration(milliseconds: 1),
-//                  fadeInDuration: Duration(milliseconds: 200),
-//                  width: requestWidth,
-//                  height: requestHeight,
-//                  fit: BoxFit.contain,
-//                ),
-//              ),
-//            ],
-//          ),
-//        ),
     );
   }
 }
@@ -83,7 +51,7 @@ class FullscreenBody extends StatefulWidget {
 
 class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProviderStateMixin {
   bool _isInitialScale = true;
-  int _currentHorizontalPage, _currentVerticalPage = 0;
+  int _currentHorizontalPage, _currentVerticalPage = imagePage;
   PageController _horizontalPager, _verticalPager;
   ValueNotifier<bool> _overlayVisible = ValueNotifier(true);
   AnimationController _overlayAnimationController;
@@ -97,6 +65,10 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
 
   List<ImageEntry> get entries => widget.collection.sortedEntries;
 
+  static const transitionPage = 0;
+  static const imagePage = 1;
+  static const infoPage = 2;
+
   @override
   void initState() {
     super.initState();
@@ -119,7 +91,7 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
     _overlayVisible.addListener(onOverlayVisibleChange);
     _actionDelegate = FullscreenActionDelegate(
       collection: collection,
-      showInfo: () => goToVerticalPage(1),
+      showInfo: () => goToVerticalPage(infoPage),
     );
     initVideoController();
     initOverlay();
@@ -144,11 +116,11 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
     final entry = _currentHorizontalPage != null && _currentHorizontalPage < entries.length ? entries[_currentHorizontalPage] : null;
     return WillPopScope(
       onWillPop: () {
-        if (_currentVerticalPage == 1) {
-          goToVerticalPage(0);
+        if (_currentVerticalPage == infoPage) {
+          goToVerticalPage(imagePage);
           return Future.value(false);
         }
-        SystemChrome.setEnabledSystemUIOverlays(SystemUiOverlay.values);
+        _onLeave();
         return Future.value(true);
       },
       child: Stack(
@@ -157,9 +129,12 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
             scrollDirection: Axis.vertical,
             controller: _verticalPager,
             physics: _isInitialScale ? PageScrollPhysics() : NeverScrollableScrollPhysics(),
-            onPageChanged: (page) => setState(() => _currentVerticalPage = page),
+            onPageChanged: _onVerticalPageChanged,
             children: [
-              ImagePage(
+              SizedBox(),
+              Container(
+                color: Colors.black,
+                child: ImagePage(
                   collection: collection,
                   pageController: _horizontalPager,
                   onTap: () => _overlayVisible.value = !_overlayVisible.value,
@@ -167,9 +142,10 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
                   onScaleChanged: (state) => setState(() => _isInitialScale = state == PhotoViewScaleState.initial),
                   videoControllers: _videoControllers,
                 ),
+              ),
               NotificationListener(
                 onNotification: (notification) {
-                  if (notification is BackUpNotification) goToVerticalPage(0);
+                  if (notification is BackUpNotification) goToVerticalPage(imagePage);
                   return false;
                 },
                 child: InfoPage(collection: collection, entry: entry),
@@ -183,7 +159,7 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
   }
 
   List<Widget> _buildOverlay(ImageEntry entry) {
-    if (entry == null || _currentVerticalPage != 0) return [];
+    if (entry == null || _currentVerticalPage != imagePage) return [];
     final videoController = entry.isVideo ? _videoControllers.firstWhere((kv) => kv.item1 == entry.path, orElse: () => null)?.item2 : null;
     return [
       FullscreenTopOverlay(
@@ -229,15 +205,29 @@ class FullscreenBodyState extends State<FullscreenBody> with SingleTickerProvide
     );
   }
 
+  _onVerticalPageChanged(page) {
+    setState(() => _currentVerticalPage = page);
+    if (_currentVerticalPage == transitionPage) {
+      _onLeave();
+      Navigator.pop(context);
+    }
+  }
+
+  _onLeave() => _showSystemUI();
+
+  _showSystemUI() => SystemChrome.setEnabledSystemUIOverlays(SystemUiOverlay.values);
+
+  _hideSystemUI() => SystemChrome.setEnabledSystemUIOverlays([]);
+
   onOverlayVisibleChange() async {
     if (_overlayVisible.value) {
-      SystemChrome.setEnabledSystemUIOverlays(SystemUiOverlay.values);
+      _showSystemUI();
       _overlayAnimationController.forward();
     } else {
       final mediaQuery = MediaQuery.of(context);
       _frozenViewInsets = mediaQuery.viewInsets;
       _frozenViewPadding = mediaQuery.viewPadding;
-      SystemChrome.setEnabledSystemUIOverlays([]);
+      _hideSystemUI();
       await _overlayAnimationController.reverse();
       _frozenViewInsets = null;
       _frozenViewPadding = null;

lib/widgets/fullscreen/image_page.dart

@@ -73,6 +73,7 @@ class ImagePageState extends State<ImagePage> with AutomaticKeepAliveClientMixin
       loadingChild: Center(
         child: CircularProgressIndicator(),
       ),
+      backgroundDecoration: BoxDecoration(color: Colors.transparent),
       pageController: widget.pageController,
       onPageChanged: widget.onPageChanged,
       scaleStateChangedCallback: widget.onScaleChanged,

pubspec.lock

@@ -100,7 +100,7 @@ packages:
       name: flutter_svg
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.14.4"
+    version: "0.15.0"
   flutter_test:
     dependency: "direct dev"
     description: flutter
@@ -119,7 +119,7 @@ packages:
       name: google_maps_flutter
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.5.21+8"
+    version: "0.5.21+12"
   image:
     dependency: transitive
     description:
@@ -203,7 +203,7 @@ packages:
       name: photo_view
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.8.0"
+    version: "0.9.0"
   printing:
     dependency: "direct main"
     description:
@@ -231,7 +231,7 @@ packages:
       name: shared_preferences
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.5.4+3"
+    version: "0.5.4+5"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -278,7 +278,7 @@ packages:
       name: synchronized
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0+1"
+    version: "2.1.0+2"
   term_glyph:
     dependency: transitive
     description:
@@ -334,7 +334,7 @@ packages:
       name: video_player
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.10.2+5"
+    version: "0.10.3+1"
   xml:
     dependency: transitive
     description:
@@ -344,4 +344,4 @@ packages:
     version: "3.5.0"
 sdks:
   dart: ">=2.5.0 <3.0.0"
-  flutter: ">=1.9.1 <2.0.0"
+  flutter: ">=1.9.1+hotfix.5 <2.0.0"