Replace TextField.canRequestFocus with TextField.focusNode.canRequestFocus (flutter#130164)

Simplifying the TextField API.

Author: justinmc

packages/flutter/lib/src/material/dropdown_menu.dart

@@ -4,6 +4,7 @@
 
 import 'dart:math' as math;
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
@@ -309,6 +310,7 @@ class _DropdownMenuState<T> extends State<DropdownMenu<T>> {
   int? currentHighlight;
   double? leadingPadding;
   bool _menuHasEnabledItem = false;
+  late final FocusNode _focusNode;
 
   @override
   void initState() {
@@ -326,6 +328,18 @@ class _DropdownMenuState<T> extends State<DropdownMenu<T>> {
           TextSelection.collapsed(offset: _textEditingController.text.length);
     }
     refreshLeadingPadding();
+    _focusNode = FocusNode(
+      canRequestFocus: canRequestFocus(),
+    );
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final bool widgetCanRequestFocus = canRequestFocus();
+    if (widgetCanRequestFocus != _focusNode.canRequestFocus) {
+      _focusNode.canRequestFocus = widgetCanRequestFocus;
+    }
   }
 
   @override
@@ -353,14 +367,18 @@ class _DropdownMenuState<T> extends State<DropdownMenu<T>> {
             TextSelection.collapsed(offset: _textEditingController.text.length);
       }
     }
+    final bool widgetCanRequestFocus = canRequestFocus();
+    if (widgetCanRequestFocus != _focusNode.canRequestFocus) {
+      _focusNode.canRequestFocus = widgetCanRequestFocus;
+    }
   }
 
   bool canRequestFocus() {
     if (widget.requestFocusOnTap != null) {
       return widget.requestFocusOnTap!;
     }
 
-    switch (Theme.of(context).platform) {
+    switch (defaultTargetPlatform) {
       case TargetPlatform.iOS:
       case TargetPlatform.android:
       case TargetPlatform.fuchsia:
@@ -592,7 +610,8 @@ class _DropdownMenuState<T> extends State<DropdownMenu<T>> {
         final Widget textField = TextField(
             key: _anchorKey,
             mouseCursor: effectiveMouseCursor,
-            canRequestFocus: canRequestFocus(),
+            focusNode: _focusNode,
+            readOnly: !canRequestFocus(),
             enableInteractiveSelection: canRequestFocus(),
             textAlignVertical: TextAlignVertical.center,
             style: effectiveTextStyle,

packages/flutter/lib/src/material/text_field.dart

@@ -314,6 +314,10 @@ class TextField extends StatefulWidget {
     this.scribbleEnabled = true,
     this.enableIMEPersonalizedLearning = true,
     this.contextMenuBuilder = _defaultContextMenuBuilder,
+    @Deprecated(
+      'Use `focusNode` instead. '
+      'This feature was deprecated after v3.12.0-14.0.pre.',
+    )
     this.canRequestFocus = true,
     this.spellCheckConfiguration,
     this.magnifierConfiguration,
@@ -776,6 +780,10 @@ class TextField extends StatefulWidget {
   /// Defaults to true. If false, the text field will not request focus
   /// when tapped, or when its context menu is displayed. If false it will not
   /// be possible to move the focus to the text field with tab key.
+  @Deprecated(
+    'Use `focusNode` instead. '
+    'This feature was deprecated after v3.12.0-14.0.pre.',
+  )
   final bool canRequestFocus;
 
   /// {@macro flutter.widgets.undoHistory.controller}
@@ -1026,15 +1034,19 @@ class _TextFieldState extends State<TextField> with RestorationMixin implements
     if (widget.controller == null) {
       _createLocalController();
     }
-    _effectiveFocusNode.canRequestFocus = widget.canRequestFocus && _isEnabled;
+    _effectiveFocusNode.canRequestFocus = widget.focusNode == null
+      ? widget.canRequestFocus && _isEnabled
+      : widget.focusNode!.canRequestFocus && _isEnabled;
     _effectiveFocusNode.addListener(_handleFocusChanged);
   }
 
   bool get _canRequestFocus {
     final NavigationMode mode = MediaQuery.maybeNavigationModeOf(context) ?? NavigationMode.traditional;
     switch (mode) {
       case NavigationMode.traditional:
-        return widget.canRequestFocus && _isEnabled;
+        return widget.focusNode == null
+          ? widget.canRequestFocus && _isEnabled
+          : widget.focusNode!.canRequestFocus && _isEnabled;
       case NavigationMode.directional:
         return true;
     }
@@ -1086,8 +1098,8 @@ class _TextFieldState extends State<TextField> with RestorationMixin implements
   void _createLocalController([TextEditingValue? value]) {
     assert(_controller == null);
     _controller = value == null
-        ? RestorableTextEditingController()
-        : RestorableTextEditingController.fromValue(value);
+      ? RestorableTextEditingController()
+      : RestorableTextEditingController.fromValue(value);
     if (!restorePending) {
       _registerController();
     }

packages/flutter/test/material/dropdown_menu_test.dart

@@ -1232,7 +1232,7 @@ void main() {
 
     final Finder textFieldFinder = find.byType(TextField);
     final TextField result = tester.widget<TextField>(textFieldFinder);
-    expect(result.canRequestFocus, false);
+    expect(result.focusNode!.canRequestFocus, false);
   }, variant: TargetPlatformVariant.mobile());
 
   testWidgets('The text input field should be focused on desktop platforms '
@@ -1300,7 +1300,7 @@ void main() {
 
     final Finder textFieldFinder1 = find.byType(TextField);
     final TextField textField1 = tester.widget<TextField>(textFieldFinder1);
-    expect(textField1.canRequestFocus, false);
+    expect(textField1.focusNode!.canRequestFocus, false);
     // Open the dropdown menu.
     await tester.tap(textFieldFinder1);
     await tester.pump();
@@ -1329,7 +1329,7 @@ void main() {
 
     final Finder textFieldFinder = find.byType(TextField);
     final TextField textField = tester.widget<TextField>(textFieldFinder);
-    expect(textField.canRequestFocus, false);
+    expect(textField.focusNode!.canRequestFocus, false);
 
     final TestGesture gesture = await tester.createGesture(kind: PointerDeviceKind.mouse, pointer: 1);
     await gesture.moveTo(tester.getCenter(textFieldFinder));
@@ -1526,7 +1526,6 @@ void main() {
     // Item 5 should show up.
     expect(find.text('Item 5').hitTestable(), findsOneWidget);
   });
-
 }
 
 enum TestMenu {

packages/flutter/test/material/text_field_test.dart

@@ -15568,6 +15568,7 @@ void main() {
     expect(focusNode.hasFocus, isTrue);
 
     // Set canRequestFocus to false: the text field cannot be focused when it is tapped/long pressed.
+    focusNode.canRequestFocus = false;
     await tester.pumpWidget(
       boilerplate(
         child: TextField(
@@ -15749,7 +15750,9 @@ void main() {
     }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }));
 
     testWidgets('Right clicking cannot request focus if canRequestFocus is false', (WidgetTester tester) async {
-      final FocusNode focusNode = FocusNode();
+      final FocusNode focusNode = FocusNode(
+        canRequestFocus: false,
+      );
       final UniqueKey key = UniqueKey();
       await tester.pumpWidget(
         MaterialApp(