Add material state mouse cursor to TextField (#59363)

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

@@ -233,6 +233,14 @@ class _MaterialStateColor extends MaterialStateColor {
 ///
 /// This should only be used as parameters when they are documented to take
 /// [MaterialStateMouseCursor], otherwise only the default state will be used.
+///
+/// This class also predefines several kinds of material state mouse cursors.
+///
+/// See also:
+///
+///  * [MouseCursor] for introduction on the mouse cursor system.
+///  * [SystemMouseCursors], which defines cursors that are supported by
+///    native platforms.
 abstract class MaterialStateMouseCursor extends MouseCursor implements MaterialStateProperty<MouseCursor> {
   /// Creates a [MaterialStateMouseCursor].
   const MaterialStateMouseCursor();
@@ -257,22 +265,47 @@ abstract class MaterialStateMouseCursor extends MouseCursor implements MaterialS
   /// disabled, the cursor resolves to [SystemMouseCursors.basic].
   ///
   /// This cursor is the default for many Material widgets.
-  static const MaterialStateMouseCursor clickable = _ClickableMouseCursor();
+  static const MaterialStateMouseCursor clickable = _EnabledAndDisabledMouseCursor(
+    enabledCursor: SystemMouseCursors.click,
+    disabledCursor: SystemMouseCursors.basic,
+    name: 'clickable',
+  );
+
+  /// A mouse cursor for material widgets related to text, which resolves differently
+  /// when the widget is disabled.
+  ///
+  /// By default this cursor resolves to [SystemMouseCursors.text]. If the widget is
+  /// disabled, the cursor resolves to [SystemMouseCursors.basic].
+  ///
+  /// This cursor is the default for many Material widgets.
+  static const MaterialStateMouseCursor textable = _EnabledAndDisabledMouseCursor(
+    enabledCursor: SystemMouseCursors.text,
+    disabledCursor: SystemMouseCursors.basic,
+    name: 'textable',
+  );
 }
 
-class _ClickableMouseCursor extends MaterialStateMouseCursor {
-  const _ClickableMouseCursor();
+class _EnabledAndDisabledMouseCursor extends MaterialStateMouseCursor {
+  const _EnabledAndDisabledMouseCursor({
+    this.enabledCursor,
+    this.disabledCursor,
+    this.name,
+  });
+
+  final MouseCursor enabledCursor;
+  final MouseCursor disabledCursor;
+  final String name;
 
   @override
   MouseCursor resolve(Set<MaterialState> states) {
     if (states.contains(MaterialState.disabled)) {
-      return SystemMouseCursors.basic;
+      return disabledCursor;
     }
-    return SystemMouseCursors.click;
+    return enabledCursor;
   }
 
   @override
-  String get debugDescription => 'MaterialStateMouseCursor(clickable)';
+  String get debugDescription => 'MaterialStateMouseCursor($name)';
 }
 
 /// Interface for classes that can return a value of type `T` based on a set of

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

@@ -18,6 +18,7 @@ import 'feedback.dart';
 import 'input_decorator.dart';
 import 'material.dart';
 import 'material_localizations.dart';
+import 'material_state.dart';
 import 'selectable_text.dart' show iOSHorizontalOffset;
 import 'text_selection.dart';
 import 'theme.dart';
@@ -346,6 +347,7 @@ class TextField extends StatefulWidget {
     this.dragStartBehavior = DragStartBehavior.start,
     this.enableInteractiveSelection = true,
     this.onTap,
+    this.mouseCursor,
     this.buildCounter,
     this.scrollController,
     this.scrollPhysics,
@@ -685,6 +687,25 @@ class TextField extends StatefulWidget {
   /// {@endtemplate}
   final GestureTapCallback onTap;
 
+  /// The cursor for a mouse pointer when it enters or is hovering over the
+  /// widget.
+  ///
+  /// If [mouseCursor] is a [MaterialStateProperty<MouseCursor>],
+  /// [MaterialStateProperty.resolve] is used for the following [MaterialState]s:
+  ///
+  ///  * [MaterialState.error].
+  ///  * [MaterialState.hovered].
+  ///  * [MaterialState.focused].
+  ///  * [MaterialState.disabled].
+  ///
+  /// If this property is null, [MaterialStateMouseCursor.textable] will be used.
+  ///
+  /// The [mouseCursor] is the only property of [TextField] that controls the
+  /// appearance of the mouse pointer. All other properties related to "cursor"
+  /// stand for the text cursor, which is usually a blinking vertical line at
+  /// the editing position.
+  final MouseCursor mouseCursor;
+
   /// Callback that generates a custom [InputDecorator.counter] widget.
   ///
   /// See [InputCounterWidgetBuilder] for an explanation of the passed in
@@ -799,6 +820,10 @@ class _TextFieldState extends State<TextField> implements TextSelectionGestureDe
 
   int get _currentLength => _effectiveController.value.text.runes.length;
 
+  bool get _hasIntrinsicError => widget.maxLength != null && widget.maxLength > 0 && _effectiveController.value.text.runes.length > widget.maxLength;
+
+  bool get _hasError => widget.decoration?.errorText != null || _hasIntrinsicError;
+
   InputDecoration _getEffectiveDecoration() {
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
     final ThemeData themeData = Theme.of(context);
@@ -849,17 +874,16 @@ class _TextFieldState extends State<TextField> implements TextSelectionGestureDe
       counterText += '/${widget.maxLength}';
       final int remaining = (widget.maxLength - currentLength).clamp(0, widget.maxLength) as int;
       semanticCounterText = localizations.remainingTextFieldCharacterCount(remaining);
+    }
 
-      // Handle length exceeds maxLength
-      if (_effectiveController.value.text.runes.length > widget.maxLength) {
-        return effectiveDecoration.copyWith(
-          errorText: effectiveDecoration.errorText ?? '',
-          counterStyle: effectiveDecoration.errorStyle
-            ?? themeData.textTheme.caption.copyWith(color: themeData.errorColor),
-          counterText: counterText,
-          semanticCounterText: semanticCounterText,
-        );
-      }
+    if (_hasIntrinsicError) {
+      return effectiveDecoration.copyWith(
+        errorText: effectiveDecoration.errorText ?? '',
+        counterStyle: effectiveDecoration.errorStyle
+          ?? themeData.textTheme.caption.copyWith(color: themeData.errorColor),
+        counterText: counterText,
+        semanticCounterText: semanticCounterText,
+      );
     }
 
     return effectiveDecoration.copyWith(
@@ -1113,10 +1137,20 @@ class _TextFieldState extends State<TextField> implements TextSelectionGestureDe
         child: child,
       );
     }
+    final MouseCursor effectiveMouseCursor = MaterialStateProperty.resolveAs<MouseCursor>(
+      widget.mouseCursor ?? MaterialStateMouseCursor.textable,
+      <MaterialState>{
+        if (!_isEnabled) MaterialState.disabled,
+        if (_isHovering) MaterialState.hovered,
+        if (focusNode.hasFocus) MaterialState.focused,
+        if (_hasError) MaterialState.error,
+      },
+    );
+
     return IgnorePointer(
       ignoring: !_isEnabled,
       child: MouseRegion(
-        cursor: SystemMouseCursors.text,
+        cursor: effectiveMouseCursor,
         onEnter: (PointerEnterEvent event) => _handleHover(true),
         onExit: (PointerExitEvent event) => _handleHover(false),
         child: AnimatedBuilder(

packages/flutter/lib/src/widgets/editable_text.dart

@@ -995,8 +995,9 @@ class EditableText extends StatefulWidget {
   /// If this property is null, [SystemMouseCursors.text] will be used.
   ///
   /// The [mouseCursor] is the only property of [EditableText] that controls the
-  /// mouse pointer. All other properties related to "cursor" stands for the text
-  /// cursor, which is usually a blinking vertical line at the editing position.
+  /// appearance of the mouse pointer. All other properties related to "cursor"
+  /// stands for the text cursor, which is usually a blinking vertical line at
+  /// the editing position.
   final MouseCursor mouseCursor;
 
   /// If true, the [RenderEditable] created by this widget will not handle

packages/flutter/test/material/text_field_test.dart

@@ -7941,26 +7941,74 @@ void main() {
     await tester.pumpWidget(
       const MaterialApp(
         home: Material(
-          child: TextField(
-            decoration: InputDecoration(
-              // Add an icon so that the left edge is not the text area
-              icon: Icon(Icons.person),
+          child: MouseRegion(
+            cursor: SystemMouseCursors.forbidden,
+            child: TextField(
+              mouseCursor: SystemMouseCursors.grab,
+              decoration: InputDecoration(
+                // Add an icon so that the left edge is not the text area
+                icon: Icon(Icons.person),
+              ),
             ),
           ),
         ),
       ),
     );
 
+    // Center, which is within the text area
+    final Offset center = tester.getCenter(find.byType(TextField));
+    // Top left, which is not the text area
+    final Offset edge = tester.getTopLeft(find.byType(TextField)) + const Offset(1, 1);
+
     final TestGesture gesture = await tester.createGesture(kind: PointerDeviceKind.mouse, pointer: 1);
-    await gesture.addPointer(location: tester.getCenter(find.byType(TextField)));
+    await gesture.addPointer(location: center);
     addTearDown(gesture.removePointer);
 
     await tester.pump();
 
-    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
+    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.grab);
+
+    // Test default cursor
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: Material(
+          child: MouseRegion(
+            cursor: SystemMouseCursors.forbidden,
+            child: TextField(
+              decoration: InputDecoration(
+                icon: Icon(Icons.person),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
 
-    // Test top left, which is not the text area
-    await gesture.moveTo(tester.getTopLeft(find.byType(TextField)) + const Offset(1, 1));
     expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
+    await gesture.moveTo(edge);
+    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.text);
+    await gesture.moveTo(center);
+
+    // Test default cursor when disabled
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: Material(
+          child: MouseRegion(
+            cursor: SystemMouseCursors.forbidden,
+            child: TextField(
+              enabled: false,
+              decoration: InputDecoration(
+                icon: Icon(Icons.person),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
+    await gesture.moveTo(edge);
+    expect(RendererBinding.instance.mouseTracker.debugDeviceActiveCursor(1), SystemMouseCursors.basic);
+    await gesture.moveTo(center);
   });
 }