feat: 添加键盘状态同步功能，优化 H5ShellPage 的用户体验

lib/main.dart

@@ -19,6 +19,7 @@ const _shellBrandingChannel =
     MethodChannel('io.openim.flutter.im_webview_app/shell_branding');
 const _androidFilePickerChannel =
     MethodChannel('io.openim.flutter.openim/file_picker');
+const _keyboardAnimationDuration = Duration(milliseconds: 250);
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
@@ -104,6 +105,9 @@ class _H5ShellPageState extends State<H5ShellPage> {
 
   bool _shellBrandingLoaded = false;
   int _currentLineIndex = 0;
+  double _lastKeyboardInset = 0;
+  bool _lastKeyboardVisible = false;
+  int _keyboardSyncToken = 0;
   late ShellBranding _shellBranding;
 
   H5Line get _currentLine => _h5Lines[_currentLineIndex];
@@ -244,6 +248,7 @@ class _H5ShellPageState extends State<H5ShellPage> {
     await _loadShellBrandingIfNeeded();
     await _syncShellBranding(lineIndex);
     await _installRouteObserver(lineIndex);
+    await _syncKeyboardState(lineIndex);
     final slot = _lineSlots[lineIndex];
     slot.progress = 100;
     if (mounted &&
@@ -265,6 +270,8 @@ class _H5ShellPageState extends State<H5ShellPage> {
         _hideShellCover(lineIndex);
       } else if (decoded is Map && decoded['type'] == 'route-changed') {
         _updateSlotUrl(lineIndex, decoded['url']?.toString());
+      } else if (decoded is Map && decoded['type'] == 'keyboard-bridge-ready') {
+        unawaited(_syncKeyboardState(lineIndex));
       }
     } catch (_) {
       if (message.message == 'first-screen-ready') {
@@ -296,6 +303,8 @@ class _H5ShellPageState extends State<H5ShellPage> {
           );
         case 'openAppSettings':
           unawaited(openAppSettings());
+        case 'keyboard-bridge-ready':
+          unawaited(_syncKeyboardState(lineIndex));
       }
     } catch (_) {
       // Ignore malformed shell messages from web content.
@@ -366,6 +375,53 @@ class _H5ShellPageState extends State<H5ShellPage> {
     return _runJavaScriptSafely(lineIndex, script);
   }
 
+  void _scheduleKeyboardStateSync(double bottomInset) {
+    final nextInset = bottomInset < 1 ? 0.0 : bottomInset;
+    final nextVisible = nextInset > 0;
+    if ((nextInset - _lastKeyboardInset).abs() < 1 &&
+        nextVisible == _lastKeyboardVisible) {
+      return;
+    }
+
+    _lastKeyboardInset = nextInset;
+    _lastKeyboardVisible = nextVisible;
+    final token = ++_keyboardSyncToken;
+
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted || token != _keyboardSyncToken) {
+        return;
+      }
+      unawaited(_syncKeyboardState(_currentLineIndex));
+    });
+  }
+
+  Future<void> _syncKeyboardState(int lineIndex) {
+    if (lineIndex < 0 || lineIndex >= _lineSlots.length) {
+      return Future<void>.value();
+    }
+
+    final payload = jsonEncode({
+      'height': _lastKeyboardInset.round(),
+      'visible': _lastKeyboardVisible,
+      'duration': _keyboardAnimationDuration.inMilliseconds,
+    });
+    final script = '''
+(() => {
+  try {
+    const keyboard = $payload;
+    if (typeof window.__OPENIM_KEYBOARD_UPDATE__ === 'function') {
+      window.__OPENIM_KEYBOARD_UPDATE__(keyboard);
+      return;
+    }
+    if (typeof window.openIMKeyboardUpdate === 'function') {
+      window.openIMKeyboardUpdate(keyboard);
+    }
+  } catch (_) {}
+})();
+''';
+    return _runJavaScriptSafely(lineIndex, script);
+  }
+
   Future<void> _installRouteObserver(int lineIndex) {
     const script = '''
 (() => {
@@ -551,6 +607,7 @@ class _H5ShellPageState extends State<H5ShellPage> {
     }
 
     await _ensureLineLoaded(safeIndex);
+    await _syncKeyboardState(safeIndex);
   }
 
   Widget _buildWebViewWidget(int index) {
@@ -635,6 +692,7 @@ class _H5ShellPageState extends State<H5ShellPage> {
     final currentSlot = _currentSlot;
     final topInset = MediaQuery.paddingOf(context).top;
     final bottomInset = MediaQuery.viewInsetsOf(context).bottom;
+    _scheduleKeyboardStateSync(bottomInset);
     final showLineSwitch = !currentSlot.showShellCover &&
         currentSlot.loadError == null &&
         currentSlot.isLoginPage &&