From c4e44183b0c4bbbfe9b23f3fabebbad2f868bd32 Mon Sep 17 00:00:00 2001
From: Thibault Deckers <thibault.deckers@gmail.com>
Date: Fri, 16 Jul 2021 09:50:18 +0900
Subject: [PATCH] minor fix

---
 lib/widgets/viewer/entry_viewer_stack.dart | 30 +++++++++++++++++++---
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/lib/widgets/viewer/entry_viewer_stack.dart b/lib/widgets/viewer/entry_viewer_stack.dart
index 4ea43fd72..5b38033bd 100644
--- a/lib/widgets/viewer/entry_viewer_stack.dart
+++ b/lib/widgets/viewer/entry_viewer_stack.dart
@@ -18,6 +18,7 @@ import 'package:aves/widgets/viewer/entry_vertical_pager.dart';
 import 'package:aves/widgets/viewer/hero.dart';
 import 'package:aves/widgets/viewer/info/notifications.dart';
 import 'package:aves/widgets/viewer/multipage/conductor.dart';
+import 'package:aves/widgets/viewer/multipage/controller.dart';
 import 'package:aves/widgets/viewer/overlay/bottom/common.dart';
 import 'package:aves/widgets/viewer/overlay/bottom/panorama.dart';
 import 'package:aves/widgets/viewer/overlay/bottom/video.dart';
@@ -62,6 +63,7 @@ class _EntryViewerStackState extends State<EntryViewerStack> with FeedbackMixin,
   EdgeInsets? _frozenViewInsets, _frozenViewPadding;
   late VideoActionDelegate _videoActionDelegate;
   final List<Tuple2<String, ValueNotifier<ViewState>>> _viewStateNotifiers = [];
+  final Map<MultiPageController, Future<void> Function()> _multiPageControllerPageListeners = {};
   final ValueNotifier<HeroInfo?> _heroInfoNotifier = ValueNotifier(null);
   bool _isEntryTracked = true;
 
@@ -111,7 +113,7 @@ class _EntryViewerStackState extends State<EntryViewerStack> with FeedbackMixin,
     _videoActionDelegate = VideoActionDelegate(
       collection: collection,
     );
-    _initEntryControllers();
+    _initEntryControllers(entry);
     _registerWidget(widget);
     WidgetsBinding.instance!.addObserver(this);
     WidgetsBinding.instance!.addPostFrameCallback((_) => _initOverlay());
@@ -129,6 +131,7 @@ class _EntryViewerStackState extends State<EntryViewerStack> with FeedbackMixin,
 
   @override
   void dispose() {
+    _cleanEntryControllers(_entryNotifier.value);
     _videoActionDelegate.dispose();
     _overlayAnimationController.dispose();
     _overlayVisible.removeListener(_onOverlayVisibleChange);
@@ -454,10 +457,11 @@ class _EntryViewerStackState extends State<EntryViewerStack> with FeedbackMixin,
 
     final newEntry = _currentHorizontalPage < entries.length ? entries[_currentHorizontalPage] : null;
     if (_entryNotifier.value == newEntry) return;
+    _cleanEntryControllers(_entryNotifier.value);
     _entryNotifier.value = newEntry;
     _isEntryTracked = false;
     await _pauseVideoControllers();
-    await _initEntryControllers();
+    await _initEntryControllers(newEntry);
   }
 
   void _popVisual() {
@@ -549,8 +553,7 @@ class _EntryViewerStackState extends State<EntryViewerStack> with FeedbackMixin,
 
   // state controllers/monitors
 
-  Future<void> _initEntryControllers() async {
-    final entry = _entryNotifier.value;
+  Future<void> _initEntryControllers(AvesEntry? entry) async {
     if (entry == null) return;
 
     _initViewStateController(entry);
@@ -562,6 +565,14 @@ class _EntryViewerStackState extends State<EntryViewerStack> with FeedbackMixin,
     }
   }
 
+  void _cleanEntryControllers(AvesEntry? entry) {
+    if (entry == null) return;
+
+    if (entry.isMultiPage) {
+      _cleanMultiPageController(entry);
+    }
+  }
+
   void _initViewStateController(AvesEntry entry) {
     final uri = entry.uri;
     var controller = _viewStateNotifiers.firstWhereOrNull((kv) => kv.item1 == uri);
@@ -617,11 +628,22 @@ class _EntryViewerStackState extends State<EntryViewerStack> with FeedbackMixin,
         }
       }
 
+      _multiPageControllerPageListeners[multiPageController] = _onPageChange;
       multiPageController.pageNotifier.addListener(_onPageChange);
       await _onPageChange();
     }
   }
 
+  Future<void> _cleanMultiPageController(AvesEntry entry) async {
+    final multiPageController = _multiPageControllerPageListeners.keys.firstWhereOrNull((v) => v.entry == entry);
+    if (multiPageController != null) {
+      final _onPageChange = _multiPageControllerPageListeners.remove(multiPageController);
+      if (_onPageChange != null) {
+        multiPageController.pageNotifier.removeListener(_onPageChange);
+      }
+    }
+  }
+
   Future<void> _playVideo(AvesVideoController videoController, bool Function() isCurrent) async {
     // video decoding may fail or have initial artifacts when the player initializes
     // during this widget initialization (because of the page transition and hero animation?)