From 6d8c850ee7df358115d349ec039efd5f4568a648 Mon Sep 17 00:00:00 2001
From: Jonah Williams <jonahwilliams@google.com>
Date: Fri, 9 Jul 2021 12:06:05 -0700
Subject: [PATCH] [flutter] tab navigation does not notify the focus scope node
 (#86141)

---
 packages/flutter/lib/src/widgets/routes.dart  | 15 +----
 .../test/material/text_field_focus_test.dart  | 59 +++++++++++++++++++
 2 files changed, 62 insertions(+), 12 deletions(-)

diff --git a/packages/flutter/lib/src/widgets/routes.dart b/packages/flutter/lib/src/widgets/routes.dart
index f7393ff36f..e7ac262e0f 100644
--- a/packages/flutter/lib/src/widgets/routes.dart
+++ b/packages/flutter/lib/src/widgets/routes.dart
@@ -2011,11 +2011,8 @@ class _FocusTrap extends SingleChildRenderObjectWidget {
 }
 
 class _RenderFocusTrap extends RenderProxyBoxWithHitTestBehavior {
-  _RenderFocusTrap(this._focusScopeNode) {
-    focusScopeNode.addListener(_currentFocusListener);
-  }
+  _RenderFocusTrap(this._focusScopeNode);
 
-  FocusNode? currentFocus;
   Rect? currentFocusRect;
   Expando<BoxHitTestResult> cachedResults = Expando<BoxHitTestResult>();
 
@@ -2024,13 +2021,7 @@ class _RenderFocusTrap extends RenderProxyBoxWithHitTestBehavior {
   set focusScopeNode(FocusScopeNode value) {
     if (focusScopeNode == value)
       return;
-    focusScopeNode.removeListener(_currentFocusListener);
     _focusScopeNode = value;
-    focusScopeNode.addListener(_currentFocusListener);
-  }
-
-  void _currentFocusListener() {
-    currentFocus = focusScopeNode.focusedChild;
   }
 
   @override
@@ -2069,11 +2060,11 @@ class _RenderFocusTrap extends RenderProxyBoxWithHitTestBehavior {
       || event.buttons != kPrimaryButton
       || event.kind != PointerDeviceKind.mouse
       || _shouldIgnoreEvents
-      || currentFocus == null) {
+      || _focusScopeNode.focusedChild == null) {
       return;
     }
     final BoxHitTestResult? result = cachedResults[entry];
-    final FocusNode? focusNode = currentFocus;
+    final FocusNode? focusNode = _focusScopeNode.focusedChild;
     if (focusNode == null || result == null)
       return;
 
diff --git a/packages/flutter/test/material/text_field_focus_test.dart b/packages/flutter/test/material/text_field_focus_test.dart
index 5baf32304a..f641aab65a 100644
--- a/packages/flutter/test/material/text_field_focus_test.dart
+++ b/packages/flutter/test/material/text_field_focus_test.dart
@@ -5,6 +5,7 @@
 import 'dart:ui';
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
@@ -429,4 +430,62 @@ void main() {
     expect(focusNodeA.hasFocus, false);
     expect(focusNodeB.hasFocus, true);
   }, variant: TargetPlatformVariant.desktop());
+
+  testWidgets('A Focused text-field will lose focus when clicking outside of its hitbox with a mouse on desktop after tab navigation', (WidgetTester tester) async {
+    final FocusNode focusNodeA = FocusNode();
+    final FocusNode focusNodeB = FocusNode();
+    final Key key = UniqueKey();
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: ListView(
+            children: <Widget>[
+              const TextField(),
+              const TextField(),
+              TextField(
+                focusNode: focusNodeA,
+              ),
+              Container(
+                key: key,
+                height: 200,
+              ),
+              TextField(
+                focusNode: focusNodeB,
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+    // Tab over to the 3rd text field.
+    for (int i = 0; i < 3; i += 1) {
+      await tester.sendKeyDownEvent(LogicalKeyboardKey.tab);
+      await tester.sendKeyUpEvent(LogicalKeyboardKey.tab);
+    }
+
+    expect(focusNodeA.hasFocus, true);
+    expect(focusNodeB.hasFocus, false);
+
+    // Click on the container to not hit either text field.
+    final TestGesture down2 = await tester.startGesture(tester.getCenter(find.byKey(key)), kind: PointerDeviceKind.mouse);
+    await tester.pump();
+    await tester.pumpAndSettle();
+    await down2.up();
+    await down2.removePointer();
+
+    expect(focusNodeA.hasFocus, false);
+    expect(focusNodeB.hasFocus, false);
+
+    // Second text field can still gain focus.
+
+    final TestGesture down3 = await tester.startGesture(tester.getCenter(find.byType(TextField).last), kind: PointerDeviceKind.mouse);
+    await tester.pump();
+    await tester.pumpAndSettle();
+    await down3.up();
+    await down3.removePointer();
+
+    expect(focusNodeA.hasFocus, false);
+    expect(focusNodeB.hasFocus, true);
+  }, variant: TargetPlatformVariant.desktop());
 }