tweaks

Signed-off-by: dom <githubaccount56556@proton.me>

lib/common/widgets/expandable.dart

@@ -0,0 +1,139 @@
+import 'package:flutter/material.dart';
+
+class ExpandablePanel extends StatelessWidget {
+  final bool expand;
+
+  final Widget collapsed;
+
+  final Widget expanded;
+
+  const ExpandablePanel({
+    super.key,
+    required this.expand,
+    required this.collapsed,
+    required this.expanded,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return _AnimatedCross(
+      alignment: .topLeft,
+      firstChild: collapsed,
+      secondChild: expanded,
+      sizeCurve: Curves.linear,
+      crossFadeState: expand ? .showSecond : .showFirst,
+      duration: const Duration(milliseconds: 300),
+    );
+  }
+}
+
+/// ref [AnimatedCrossFade]
+class _AnimatedCross extends StatefulWidget {
+  const _AnimatedCross({
+    required this.firstChild,
+    required this.secondChild,
+    this.sizeCurve = Curves.linear,
+    this.alignment = Alignment.topCenter,
+    required this.crossFadeState,
+    required this.duration,
+  });
+
+  final Widget firstChild;
+
+  final Widget secondChild;
+
+  final CrossFadeState crossFadeState;
+
+  final Duration duration;
+
+  final Curve sizeCurve;
+
+  final AlignmentGeometry alignment;
+
+  @override
+  State<_AnimatedCross> createState() => _AnimatedCrossState();
+}
+
+class _AnimatedCrossState extends State<_AnimatedCross> {
+  late bool _showFirst;
+  AnimationStatus? _status;
+
+  @override
+  void initState() {
+    super.initState();
+    switch (widget.crossFadeState) {
+      case .showFirst:
+        _showFirst = true;
+      case .showSecond:
+        _showFirst = false;
+    }
+  }
+
+  @override
+  void didUpdateWidget(_AnimatedCross oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.crossFadeState != oldWidget.crossFadeState) {
+      switch (widget.crossFadeState) {
+        case .showFirst:
+          _status = .reverse;
+        case .showSecond:
+          _status = .forward;
+      }
+      _showFirst = false;
+    }
+  }
+
+  void _onEnd() {
+    if (_status == .reverse) {
+      _showFirst = true;
+    }
+    setState(() {});
+  }
+
+  Widget get firstChild => _widgetBuilder(_showFirst, widget.firstChild);
+
+  Widget get secondChild => _widgetBuilder(!_showFirst, widget.secondChild);
+
+  static Widget _widgetBuilder(bool visible, Widget child) =>
+      Opacity(opacity: visible ? 1.0 : 0.0, child: child);
+
+  @override
+  Widget build(BuildContext context) {
+    const Key kFirstChildKey = ValueKey<CrossFadeState>(.showFirst);
+    const Key kSecondChildKey = ValueKey<CrossFadeState>(.showSecond);
+
+    final Key topKey;
+    Widget topChild;
+    final Key bottomKey;
+    Widget bottomChild;
+
+    switch (widget.crossFadeState) {
+      case .showFirst:
+        topKey = kFirstChildKey;
+        topChild = firstChild;
+        bottomKey = kSecondChildKey;
+        bottomChild = secondChild;
+      case .showSecond:
+        topKey = kSecondChildKey;
+        topChild = secondChild;
+        bottomKey = kFirstChildKey;
+        bottomChild = firstChild;
+    }
+
+    return ClipRect(
+      child: AnimatedSize(
+        clipBehavior: .none,
+        alignment: widget.alignment,
+        duration: widget.duration,
+        curve: widget.sizeCurve,
+        onEnd: _onEnd,
+        child: AnimatedCrossFade.defaultLayoutBuilder(
+          topChild,
+          topKey,
+          bottomChild,
+          bottomKey,
+        ),
+      ),
+    );
+  }
+}

lib/common/widgets/flutter/page/page_view.dart

@@ -430,49 +430,51 @@ class _PageViewState<T extends HorizontalDragGestureRecognizer>
                     widget.scrollBehavior?.getScrollPhysics(context),
         );
 
-    return NotificationListener<ScrollNotification>(
-      onNotification: (ScrollNotification notification) {
-        if (notification.depth == 0 &&
-            widget.onPageChanged != null &&
-            notification is ScrollUpdateNotification) {
-          final metrics = notification.metrics as PageMetrics;
-          final int currentPage = metrics.page!.round();
-          if (currentPage != _lastReportedPage) {
-            _lastReportedPage = currentPage;
-            widget.onPageChanged!(currentPage);
-          }
-        }
-        return false;
+    final child = Scrollable<T>(
+      dragStartBehavior: widget.dragStartBehavior,
+      axisDirection: axisDirection,
+      controller: _controller,
+      physics: physics,
+      restorationId: widget.restorationId,
+      hitTestBehavior: widget.hitTestBehavior,
+      scrollBehavior:
+          widget.scrollBehavior ??
+          ScrollConfiguration.of(context).copyWith(scrollbars: false),
+      viewportBuilder: (BuildContext context, ViewportOffset position) {
+        return Viewport(
+          scrollCacheExtent: widget.scrollCacheExtent,
+          axisDirection: axisDirection,
+          offset: position,
+          clipBehavior: widget.clipBehavior,
+          slivers: <Widget>[
+            SliverFillViewport(
+              viewportFraction: _controller.viewportFraction,
+              delegate: widget.childrenDelegate,
+              padEnds: widget.padEnds,
+              allowImplicitScrolling: widget.allowImplicitScrolling,
+            ),
+          ],
+        );
       },
-      child: Scrollable<T>(
-        dragStartBehavior: widget.dragStartBehavior,
-        axisDirection: axisDirection,
-        controller: _controller,
-        physics: physics,
-        restorationId: widget.restorationId,
-        hitTestBehavior: widget.hitTestBehavior,
-        scrollBehavior:
-            widget.scrollBehavior ??
-            ScrollConfiguration.of(context).copyWith(scrollbars: false),
-        viewportBuilder: (BuildContext context, ViewportOffset position) {
-          return Viewport(
-            scrollCacheExtent: widget.scrollCacheExtent,
-            axisDirection: axisDirection,
-            offset: position,
-            clipBehavior: widget.clipBehavior,
-            slivers: <Widget>[
-              SliverFillViewport(
-                viewportFraction: _controller.viewportFraction,
-                delegate: widget.childrenDelegate,
-                padEnds: widget.padEnds,
-                allowImplicitScrolling: widget.allowImplicitScrolling,
-              ),
-            ],
-          );
-        },
-        horizontalDragGestureRecognizer: widget.horizontalDragGestureRecognizer,
-      ),
+      horizontalDragGestureRecognizer: widget.horizontalDragGestureRecognizer,
     );
+    if (widget.onPageChanged != null) {
+      return NotificationListener<ScrollEndNotification>(
+        onNotification: (notification) {
+          if (notification.depth == 0) {
+            final metrics = notification.metrics as PageMetrics;
+            final int currentPage = metrics.page!.round();
+            if (currentPage != _lastReportedPage) {
+              _lastReportedPage = currentPage;
+              widget.onPageChanged!(currentPage);
+            }
+          }
+          return false;
+        },
+        child: child,
+      );
+    }
+    return child;
   }
 
   @override

lib/common/widgets/sliver/sliver_to_box_adapter.dart

@@ -78,7 +78,7 @@ class RenderSliverToBoxWithVisibilityAdapter extends RenderSliverToBoxAdapter {
     if (_visible != visible) {
       _visible = visible;
       WidgetsBinding.instance.addPostFrameCallback(
-        (_) => onVisibilityChanged(visible),
+        (_) => onVisibilityChanged(!visible),
       );
     }
   }