ask for note at end of connection (#13499)

Signed-off-by: 21pages <sunboeasy@gmail.com>

flutter/lib/desktop/pages/file_manager_page.dart

@@ -3,6 +3,7 @@ import 'dart:io';
 import 'dart:math';
 
 import 'package:extended_text/extended_text.dart';
+import 'package:flutter_hbb/common/widgets/dialog.dart';
 import 'package:flutter_hbb/desktop/widgets/dragable_divider.dart';
 import 'package:percent_indicator/percent_indicator.dart';
 import 'package:desktop_drop/desktop_drop.dart';
@@ -52,7 +53,7 @@ enum MouseFocusScope {
 }
 
 class FileManagerPage extends StatefulWidget {
-  const FileManagerPage(
+  FileManagerPage(
       {Key? key,
       required this.id,
       required this.password,
@@ -67,9 +68,16 @@ class FileManagerPage extends StatefulWidget {
   final bool? forceRelay;
   final String? connToken;
   final DesktopTabController? tabController;
+  final SimpleWrapper<State<FileManagerPage>?> _lastState = SimpleWrapper(null);
+
+  FFI get ffi => (_lastState.value! as _FileManagerPageState)._ffi;
 
   @override
-  State<StatefulWidget> createState() => _FileManagerPageState();
+  State<StatefulWidget> createState() {
+    final state = _FileManagerPageState();
+    _lastState.value = state;
+    return state;
+  }
 }
 
 class _FileManagerPageState extends State<FileManagerPage>
@@ -139,12 +147,26 @@ class _FileManagerPageState extends State<FileManagerPage>
     }
   }
 
+  Widget willPopScope(Widget child) {
+    if (isWeb) {
+      return WillPopScope(
+        onWillPop: () async {
+          clientClose(_ffi.sessionId, _ffi);
+          return false;
+        },
+        child: child,
+      );
+    } else {
+      return child;
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     super.build(context);
     return Overlay(key: _overlayKeyState.key, initialEntries: [
       OverlayEntry(builder: (_) {
-        return Scaffold(
+        return willPopScope(Scaffold(
           backgroundColor: Theme.of(context).scaffoldBackgroundColor,
           body: Row(
             children: [
@@ -160,7 +182,7 @@ class _FileManagerPageState extends State<FileManagerPage>
               Flexible(flex: 2, child: statusList())
             ],
           ),
-        );
+        ));
       })
     ]);
   }