fix: unable to update selection sometimes when the editor lost focus (#509)

example/lib/home_page.dart

@@ -6,6 +6,7 @@ import 'dart:math';
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:example/pages/customize_theme_for_editor.dart';
 import 'package:example/pages/editor.dart';
+import 'package:example/pages/focus_example_for_editor.dart';
 import 'package:file_picker/file_picker.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
@@ -154,7 +155,7 @@ class _HomePageState extends State<HomePage> {
           }),
 
           // Theme Demo
-          _buildSeparator(context, 'Theme Demo'),
+          _buildSeparator(context, 'Showcases'),
           _buildListTile(context, 'Custom Theme', () {
             Navigator.push(
               context,
@@ -173,6 +174,14 @@ class _HomePageState extends State<HomePage> {
               textDirection: TextDirection.rtl,
             );
           }),
+          _buildListTile(context, 'Focus Example', () {
+            Navigator.push(
+              context,
+              MaterialPageRoute(
+                builder: (context) => const FocusExampleForEditor(),
+              ),
+            );
+          }),
 
           // Encoder Demo
           _buildSeparator(context, 'Export To X Demo'),

example/lib/pages/focus_example_for_editor.dart

@@ -0,0 +1,69 @@
+import 'dart:convert';
+
+import 'package:appflowy_editor/appflowy_editor.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+class FocusExampleForEditor extends StatefulWidget {
+  const FocusExampleForEditor({super.key});
+
+  @override
+  State<FocusExampleForEditor> createState() => _FocusExampleForEditorState();
+}
+
+class _FocusExampleForEditorState extends State<FocusExampleForEditor> {
+  late final Future<EditorState> editorState;
+
+  @override
+  void initState() {
+    super.initState();
+
+    final jsonString = PlatformExtension.isDesktopOrWeb
+        ? rootBundle.loadString('assets/example.json')
+        : rootBundle.loadString('assets/mobile_example.json');
+    editorState = jsonString.then((value) {
+      return EditorState(
+        document: Document.fromJson(
+          Map<String, Object>.from(
+            json.decode(value),
+          ),
+        ),
+      );
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        backgroundColor: Colors.black,
+        title: const Text('Custom Theme For Editor'),
+        titleTextStyle: const TextStyle(color: Colors.white),
+        iconTheme: const IconThemeData(
+          color: Colors.white,
+        ),
+      ),
+      body: Column(
+        children: [
+          SizedBox(
+            height: 400,
+            child: FutureBuilder(
+              future: editorState,
+              builder: (context, snapshot) {
+                return !snapshot.hasData
+                    ? const Center(child: CircularProgressIndicator())
+                    : AppFlowyEditor(editorState: snapshot.data!);
+              },
+            ),
+          ),
+          const TextField(
+            textAlign: TextAlign.center,
+            decoration: InputDecoration(
+              hintText: 'Please input something ...',
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}

lib/src/editor/editor_component/service/selection/desktop_selection_service.dart

@@ -306,7 +306,12 @@ class _DesktopSelectionServiceWidgetState
     editorState.service.scrollService?.stopAutoScroll();
   }
 
-  void _updateSelection() {}
+  void _updateSelection() {
+    final selection = editorState.selectionNotifier.value;
+    if (selection == null) {
+      clearSelection();
+    }
+  }
 
   void _showContextMenu(TapDownDetails details) {
     _clearContextMenu();

test/customer/text_field_and_editor_test.dart

@@ -30,16 +30,45 @@ void main() async {
     expect(widget.focusNode.hasFocus, false);
     expect(widget.editorFocusNode.hasFocus, true);
   });
+
+  testWidgets('text field + editor, focus issue', (tester) async {
+    final editorState = EditorState.blank();
+    final widget = TextFieldAndEditor(
+      editorState: editorState,
+    );
+    await tester.pumpWidget(widget);
+    await tester.pumpAndSettle();
+
+    final selection = Selection.collapsed(Position(path: [0]));
+    editorState.selection = selection;
+
+    final textField = find.byType(TextField);
+    await tester.tap(textField);
+    await tester.pumpAndSettle();
+    expect(widget.focusNode.hasFocus, true);
+    expect(widget.editorFocusNode.hasFocus, false);
+    expect(editorState.selection, null);
+
+    await tester.tapAt(
+      tester.getTopLeft(find.byType(TextBlockComponentWidget)),
+    );
+    await tester.pumpAndSettle();
+    expect(widget.focusNode.hasFocus, false);
+    expect(widget.editorFocusNode.hasFocus, true);
+    expect(editorState.selection, selection);
+  });
 }
 
 class TextFieldAndEditor extends StatelessWidget {
   TextFieldAndEditor({
     super.key,
+    this.editorState,
   });
 
   final controller = TextEditingController();
   final focusNode = FocusNode();
   final editorFocusNode = FocusNode();
+  final EditorState? editorState;
 
   @override
   Widget build(BuildContext context) {
@@ -61,7 +90,7 @@ class TextFieldAndEditor extends StatelessWidget {
                   ),
                   child: AppFlowyEditor(
                     focusNode: editorFocusNode,
-                    editorState: EditorState.blank(),
+                    editorState: editorState ?? EditorState.blank(),
                     editorStyle: const EditorStyle.mobile(),
                   ),
                 ),