fix(auth): 登录异常改为居中吐司

lib/core/widgets/centered_error_dialog.dart

@@ -1,67 +0,0 @@
-// Author: fruit.com.cn
-
-import 'package:flutter/material.dart';
-
-import '../../l10n/app_localizations.dart';
-import '../theme/app_colors.dart';
-
-const Key _dialogKey = Key('centered-error-dialog');
-const Key _confirmKey = Key('centered-error-confirm');
-const double _dialogRadius = 16;
-const double _titleHorizontalInset = 24;
-const double _titleTopInset = 24;
-const double _contentHorizontalInset = 24;
-const double _contentTopInset = 12;
-const double _contentBottomInset = 8;
-const double _actionsHorizontalInset = 16;
-const double _actionsBottomInset = 12;
-const EdgeInsets _titlePadding = EdgeInsets.fromLTRB(
-  _titleHorizontalInset,
-  _titleTopInset,
-  _titleHorizontalInset,
-  0,
-);
-const EdgeInsets _contentPadding = EdgeInsets.fromLTRB(
-  _contentHorizontalInset,
-  _contentTopInset,
-  _contentHorizontalInset,
-  _contentBottomInset,
-);
-const EdgeInsets _actionsPadding = EdgeInsets.fromLTRB(
-  _actionsHorizontalInset,
-  0,
-  _actionsHorizontalInset,
-  _actionsBottomInset,
-);
-
-/// Shows a reusable error dialog centered on the screen.
-Future<void> showCenteredErrorDialog(
-  BuildContext context, {
-  required String title,
-  required String message,
-}) async {
-  final l10n = AppLocalizations.of(context)!;
-  await showDialog<void>(
-    context: context,
-    barrierDismissible: true,
-    builder: (dialogContext) => AlertDialog(
-      key: _dialogKey,
-      backgroundColor: AppColors.card,
-      shape: RoundedRectangleBorder(
-        borderRadius: BorderRadius.circular(_dialogRadius),
-      ),
-      titlePadding: _titlePadding,
-      contentPadding: _contentPadding,
-      title: Text(title),
-      content: Text(message),
-      actionsPadding: _actionsPadding,
-      actions: [
-        TextButton(
-          key: _confirmKey,
-          onPressed: () => Navigator.of(dialogContext).pop(),
-          child: Text(l10n.authErrorConfirm),
-        ),
-      ],
-    ),
-  );
-}

lib/core/widgets/centered_toast.dart

@@ -0,0 +1,128 @@
+// Author: fruit.com.cn
+
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+const Key _toastKey = Key('centered-toast');
+const Duration _fadeDuration = Duration(milliseconds: 200);
+const Duration _visibleDuration = Duration(seconds: 2);
+const double _toastRadius = 12;
+const double _toastMaxWidth = 320;
+const double _toastHorizontalInset = 20;
+const double _toastVerticalInset = 12;
+const double _toastBackgroundOpacity = 0.78;
+const TextStyle _toastTextStyle = TextStyle(
+  color: Colors.white,
+  fontSize: 14,
+  height: 1.4,
+  fontWeight: FontWeight.w500,
+);
+const EdgeInsets _toastPadding = EdgeInsets.symmetric(
+  horizontal: _toastHorizontalInset,
+  vertical: _toastVerticalInset,
+);
+
+OverlayEntry? _activeToast;
+
+/// Shows a lightweight centered message and replaces any active toast.
+void showCenteredToast(BuildContext context, String message) {
+  _removeActiveToast();
+  final overlay = Overlay.of(context, rootOverlay: true);
+  late final OverlayEntry entry;
+  entry = OverlayEntry(
+    builder: (_) => _CenteredToast(
+      message: message,
+      onDismissed: () {
+        if (!identical(_activeToast, entry)) return;
+        _activeToast = null;
+        if (entry.mounted) entry.remove();
+      },
+    ),
+  );
+  _activeToast = entry;
+  overlay.insert(entry);
+}
+
+void _removeActiveToast() {
+  final entry = _activeToast;
+  _activeToast = null;
+  if (entry != null && entry.mounted) entry.remove();
+}
+
+class _CenteredToast extends StatefulWidget {
+  const _CenteredToast({required this.message, required this.onDismissed});
+
+  final String message;
+  final VoidCallback onDismissed;
+
+  @override
+  State<_CenteredToast> createState() => _CenteredToastState();
+}
+
+class _CenteredToastState extends State<_CenteredToast>
+    with SingleTickerProviderStateMixin {
+  late final AnimationController _opacity = AnimationController(
+    vsync: this,
+    duration: _fadeDuration,
+  );
+  Timer? _dismissTimer;
+
+  @override
+  void initState() {
+    super.initState();
+    _opacity.forward();
+    _dismissTimer = Timer(_visibleDuration, _dismiss);
+  }
+
+  Future<void> _dismiss() async {
+    try {
+      await _opacity.reverse();
+    } on TickerCanceled {
+      return;
+    }
+    if (mounted) widget.onDismissed();
+  }
+
+  @override
+  void dispose() {
+    _dismissTimer?.cancel();
+    _opacity.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Positioned.fill(
+      child: IgnorePointer(
+        child: Center(
+          child: FadeTransition(
+            opacity: CurvedAnimation(
+              parent: _opacity,
+              curve: Curves.easeOutCubic,
+            ),
+            child: Material(
+              type: MaterialType.transparency,
+              child: Container(
+                key: _toastKey,
+                constraints: const BoxConstraints(maxWidth: _toastMaxWidth),
+                padding: _toastPadding,
+                decoration: BoxDecoration(
+                  color: Colors.black.withValues(
+                    alpha: _toastBackgroundOpacity,
+                  ),
+                  borderRadius: BorderRadius.circular(_toastRadius),
+                ),
+                child: Text(
+                  widget.message,
+                  textAlign: TextAlign.center,
+                  style: _toastTextStyle,
+                ),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}