feat: 支付页（系统浏览器收银台 + 2s 轮询确认）

lib/features/member/pay_page.dart

@@ -0,0 +1,152 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:fluttertoast/fluttertoast.dart';
+import 'package:go_router/go_router.dart';
+import 'package:url_launcher/url_launcher.dart';
+
+import 'member_provider.dart';
+
+class PayArgs {
+  final String orderNo;
+  final String payUrl;
+
+  const PayArgs({required this.orderNo, required this.payUrl});
+}
+
+enum PayPhase { launching, paying, paid, timeout, failed }
+
+/// 支付页：打开系统浏览器收银台，2s 轮询订单状态（上限 60s）
+class PayPage extends ConsumerStatefulWidget {
+  final PayArgs args;
+
+  const PayPage({super.key, required this.args});
+
+  @override
+  ConsumerState<PayPage> createState() => _PayPageState();
+}
+
+class _PayPageState extends ConsumerState<PayPage> {
+  PayPhase _phase = PayPhase.launching;
+  Timer? _timer;
+  int _elapsed = 0;
+
+  @override
+  void initState() {
+    super.initState();
+    _start();
+  }
+
+  @override
+  void dispose() {
+    _timer?.cancel();
+    super.dispose();
+  }
+
+  Future<void> _start() async {
+    try {
+      final ok = await launchUrl(Uri.parse(widget.args.payUrl),
+          mode: LaunchMode.externalApplication);
+      if (!ok) {
+        setState(() => _phase = PayPhase.failed);
+        return;
+      }
+      setState(() => _phase = PayPhase.paying);
+    } catch (e) {
+      setState(() => _phase = PayPhase.failed);
+      return;
+    }
+    _timer = Timer.periodic(const Duration(seconds: 2), (_) => _check());
+  }
+
+  Future<void> _check() async {
+    _elapsed += 2;
+    try {
+      final status = await fetchOrderStatus(ref, widget.args.orderNo);
+      if (status == 'paid') {
+        _timer?.cancel();
+        if (!mounted) return;
+        setState(() => _phase = PayPhase.paid);
+        Fluttertoast.showToast(msg: '会员开通成功');
+        return;
+      }
+      if (_elapsed >= 60) {
+        _timer?.cancel();
+        if (!mounted) return;
+        setState(() => _phase = PayPhase.timeout);
+      }
+    } catch (_) {
+      // 轮询失败不中断，下次再试
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final scheme = Theme.of(context).colorScheme;
+    return Scaffold(
+      appBar: AppBar(title: const Text('会员支付')),
+      body: Center(
+        child: Padding(
+          padding: const EdgeInsets.all(24),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              switch (_phase) {
+                PayPhase.launching ||
+                PayPhase.paying => Column(children: [
+                    const CircularProgressIndicator(),
+                    const SizedBox(height: 16),
+                    const Text('请在浏览器中完成支付，正在确认结果…'),
+                    const SizedBox(height: 8),
+                    Text('订单号 ${widget.args.orderNo}',
+                        style: const TextStyle(color: Colors.grey, fontSize: 12)),
+                    const SizedBox(height: 16),
+                    OutlinedButton(
+                      onPressed: () => _check(),
+                      child: const Text('我已完成支付'),
+                    ),
+                  ]),
+                PayPhase.paid => Column(children: [
+                    Icon(Icons.check_circle, size: 64, color: scheme.primary),
+                    const SizedBox(height: 12),
+                    const Text('支付成功，会员已开通！',
+                        style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
+                    const SizedBox(height: 16),
+                    FilledButton(
+                      onPressed: () => context.pop(),
+                      child: const Text('返回会员中心'),
+                    ),
+                  ]),
+                PayPhase.timeout => Column(children: [
+                    Icon(Icons.hourglass_empty, size: 64, color: Colors.orange),
+                    const SizedBox(height: 12),
+                    const Text('支付结果确认中'),
+                    const SizedBox(height: 8),
+                    const Text('可稍后到会员中心查看开通状态，以支付结果为准',
+                        textAlign: TextAlign.center,
+                        style: TextStyle(color: Colors.grey, fontSize: 12)),
+                    const SizedBox(height: 16),
+                    OutlinedButton(
+                      onPressed: () => context.pop(),
+                      child: const Text('返回'),
+                    ),
+                  ]),
+                PayPhase.failed => Column(children: [
+                    Icon(Icons.error_outline, size: 64, color: scheme.error),
+                    const SizedBox(height: 12),
+                    const Text('无法打开支付页面'),
+                    const SizedBox(height: 16),
+                    OutlinedButton(
+                      onPressed: () => context.pop(),
+                      child: const Text('返回'),
+                    ),
+                  ]),
+              },
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/main.dart

@@ -5,6 +5,7 @@ import 'package:go_router/go_router.dart';
 import 'features/auth/login_page.dart';
 import 'features/home/home_page.dart';
 import 'features/member/member_center_page.dart';
+import 'features/member/pay_page.dart';
 import 'features/outfit/outfit_page.dart';
 import 'features/outfit/outfit_provider.dart';
 import 'features/outfit/plan_effect_page.dart';
@@ -79,6 +80,10 @@ final routerProvider = Provider<GoRouter>((ref) {
         path: '/commercial',
         builder: (ctx, state) => const MemberCenterPage(),
       ),
+      GoRoute(
+        path: '/pay',
+        builder: (context, state) => PayPage(args: state.extra! as PayArgs),
+      ),
       GoRoute(
         path: '/plan-viewer',
         builder: (ctx, state) => const PlanViewerPage(),