fix(player): 评论面板固定半屏高度

lib/pages/player/widgets/drama_comments_sheet.dart

@@ -21,8 +21,6 @@ import '../../../core/widgets/empty_state.dart';
 import '../../../l10n/app_localizations.dart';
 import 'comment_tile.dart';
 
-const double _minSheetHeight = 280;
-const double _maxSheetHeight = 520;
 const int _maxCommentLength = 300;
 const double _composerRadius = 22;
 const double _composerHeight = 44;
@@ -50,14 +48,11 @@ class _DramaCommentsSheetState extends State<DramaCommentsSheet> {
   final _input = TextEditingController();
   final _inputFocus = FocusNode();
   final _keyboardInset = KeyboardInsetNotifier.instance;
-  final _sheetMeasureKey = GlobalKey();
   late final CommentRepository _comments;
   late final CommentController _controller;
   DramaComment? _replyTo;
   int? _serverCount;
   int _countRequest = 0;
-  double? _sheetHeightWithoutKeyboard;
-  bool _sheetMeasureScheduled = false;
 
   @override
   void initState() {
@@ -105,27 +100,6 @@ class _DramaCommentsSheetState extends State<DramaCommentsSheet> {
     _keyboardInset.value / MediaQuery.devicePixelRatioOf(context),
   );
 
-  void _measureSheetWithoutKeyboard(double keyboardHeight) {
-    if (keyboardHeight > 0 || _inputFocus.hasFocus || _sheetMeasureScheduled) {
-      return;
-    }
-    _sheetMeasureScheduled = true;
-    WidgetsBinding.instance.addPostFrameCallback((_) {
-      _sheetMeasureScheduled = false;
-      if (!mounted) return;
-      if (_inputFocus.hasFocus || _keyboardHeight(context) > 0) return;
-      final box = _sheetMeasureKey.currentContext?.findRenderObject();
-      if (box is! RenderBox || !box.hasSize) return;
-      final height = box.size.height;
-      if (!height.isFinite ||
-          (_sheetHeightWithoutKeyboard != null &&
-              (height - _sheetHeightWithoutKeyboard!).abs() < 0.5)) {
-        return;
-      }
-      setState(() => _sheetHeightWithoutKeyboard = height);
-    });
-  }
-
   Future<void> _post() async {
     if (_controller.submitting) return;
     if (!await ensureSignedIn(context) || !mounted) return;
@@ -190,20 +164,14 @@ class _DramaCommentsSheetState extends State<DramaCommentsSheet> {
 
   @override
   Widget build(BuildContext context) {
-    final screenLimit = MediaQuery.sizeOf(context).height - 24;
-    final maxHeight = screenLimit < _maxSheetHeight
-        ? screenLimit
-        : _maxSheetHeight;
+    final screenHeight = MediaQuery.sizeOf(context).height;
+    final topSafeArea = MediaQuery.paddingOf(context).top;
+    final halfHeight = (screenHeight * 0.5).roundToDouble();
+    final maxHeight = math.max(0.0, screenHeight - topSafeArea);
+    final sheetHeight = math.min(halfHeight, maxHeight);
     final inputFocused = _inputFocus.hasFocus;
     final keyboardHeight = _keyboardHeight(context);
-    final keyboardOpen = keyboardHeight > 0;
     final expanded = inputFocused;
-    final availableHeight = math.max(0.0, screenLimit - keyboardHeight);
-    final keyboardPanelHeight = math.min(
-      _sheetHeightWithoutKeyboard ?? maxHeight,
-      availableHeight,
-    );
-    _measureSheetWithoutKeyboard(keyboardHeight);
     return Stack(
       fit: StackFit.expand,
       children: [
@@ -225,53 +193,31 @@ class _DramaCommentsSheetState extends State<DramaCommentsSheet> {
               onTap: () {},
               child: KeyedSubtree(
                 key: const Key('player-comments-sheet'),
-                child: Container(
-                  decoration: const BoxDecoration(
-                    color: AppColors.card,
-                    borderRadius: BorderRadius.vertical(
-                      top: Radius.circular(_sheetRadius),
+                child: SizedBox(
+                  key: const Key('comment-sheet-constraints'),
+                  height: sheetHeight,
+                  child: Container(
+                    decoration: const BoxDecoration(
+                      color: AppColors.card,
+                      borderRadius: BorderRadius.vertical(
+                        top: Radius.circular(_sheetRadius),
+                      ),
                     ),
-                  ),
-                  child: SafeArea(
-                    top: false,
-                    child: ListenableBuilder(
-                      listenable: _controller,
-                      builder: (context, _) {
-                        final minHeight = _controller.comments.isEmpty
-                            ? (_minSheetHeight < maxHeight
-                                  ? _minSheetHeight
-                                  : maxHeight)
-                            : 0.0;
-                        return AnimatedSize(
-                          duration: const Duration(milliseconds: 200),
-                          curve: Curves.easeOut,
-                          alignment: Alignment.bottomCenter,
-                          child: KeyedSubtree(
-                            key: const Key('comment-sheet-constraints'),
-                            child: ConstrainedBox(
-                              key: _sheetMeasureKey,
-                              constraints: keyboardOpen
-                                  ? BoxConstraints.tightFor(
-                                      height: keyboardPanelHeight,
-                                    )
-                                  : BoxConstraints(
-                                      minHeight: minHeight,
-                                      maxHeight: maxHeight,
-                                    ),
-                              child: Padding(
-                                padding: const EdgeInsets.symmetric(
-                                  horizontal: 16,
-                                ),
-                                child: _content(
-                                  context,
-                                  expanded: expanded,
-                                  keyboardHeight: keyboardHeight,
-                                ),
-                              ),
+                    child: SafeArea(
+                      top: false,
+                      child: ListenableBuilder(
+                        listenable: _controller,
+                        builder: (context, _) {
+                          return Padding(
+                            padding: const EdgeInsets.symmetric(horizontal: 16),
+                            child: _content(
+                              context,
+                              expanded: expanded,
+                              keyboardHeight: keyboardHeight,
                             ),
-                          ),
-                        );
-                      },
+                          );
+                        },
+                      ),
                     ),
                   ),
                 ),
@@ -334,8 +280,7 @@ class _DramaCommentsSheetState extends State<DramaCommentsSheet> {
             ],
           ),
         ),
-        Flexible(
-          fit: FlexFit.loose,
+        Expanded(
           child: _list(
             l10n,
             composerReserve: composerReserve,
@@ -395,7 +340,6 @@ class _DramaCommentsSheetState extends State<DramaCommentsSheet> {
     }
     return ListView.builder(
       key: const Key('comment-list'),
-      shrinkWrap: true,
       padding: EdgeInsets.only(
         top: 4,
         bottom: composerReserve + keyboardHeight,