hasStrings support for eliminating clipboard notifications (#87678)

Use the hasStrings clipboard method when possible instead of reading the contents of the clipboard.

packages/flutter/lib/src/services/clipboard.dart

@@ -59,4 +59,20 @@ class Clipboard {
       return null;
     return ClipboardData(text: result['text'] as String?);
   }
+
+  /// Returns a future that resolves to true iff the clipboard contains string
+  /// data.
+  ///
+  /// See also:
+  ///   * [The iOS hasStrings method](https://developer.apple.com/documentation/uikit/uipasteboard/1829416-hasstrings?language=objc).
+  static Future<bool> hasStrings() async {
+    final Map<String, dynamic>? result = await SystemChannels.platform.invokeMethod(
+      'Clipboard.hasStrings',
+      Clipboard.kTextPlain,
+    );
+    if (result == null) {
+      return false;
+    }
+    return result['value'] as bool;
+  }
 }

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

@@ -1579,28 +1579,13 @@ class ClipboardStatusNotifier extends ValueNotifier<ClipboardStatus> with Widget
 
   /// Check the [Clipboard] and update [value] if needed.
   Future<void> update() async {
-    // iOS 14 added a notification that appears when an app accesses the
-    // clipboard. To avoid the notification, don't access the clipboard on iOS,
-    // and instead always show the paste button, even when the clipboard is
-    // empty.
-    // TODO(justinmc): Use the new iOS 14 clipboard API method hasStrings that
-    // won't trigger the notification.
-    // https://github.com/flutter/flutter/issues/60145
-    switch (defaultTargetPlatform) {
-      case TargetPlatform.iOS:
-        value = ClipboardStatus.pasteable;
-        return;
-      case TargetPlatform.android:
-      case TargetPlatform.fuchsia:
-      case TargetPlatform.linux:
-      case TargetPlatform.macOS:
-      case TargetPlatform.windows:
-        break;
+    if (_disposed) {
+      return;
     }
 
-    ClipboardData? data;
+    final bool hasStrings;
     try {
-      data = await Clipboard.getData(Clipboard.kTextPlain);
+      hasStrings = await Clipboard.hasStrings();
     } catch (stacktrace) {
       // In the case of an error from the Clipboard API, set the value to
       // unknown so that it will try to update again later.
@@ -1611,13 +1596,14 @@ class ClipboardStatusNotifier extends ValueNotifier<ClipboardStatus> with Widget
       return;
     }
 
-    final ClipboardStatus clipboardStatus = data != null && data.text != null && data.text!.isNotEmpty
+    final ClipboardStatus nextStatus = hasStrings
         ? ClipboardStatus.pasteable
         : ClipboardStatus.notPasteable;
-    if (_disposed || clipboardStatus == value) {
+
+    if (_disposed || nextStatus == value) {
       return;
     }
-    value = clipboardStatus;
+    value = nextStatus;
   }
 
   @override

packages/flutter/test/cupertino/text_field_test.dart

@@ -18,27 +18,12 @@ import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../rendering/mock_canvas.dart';
+import '../widgets/clipboard_utils.dart';
 import '../widgets/semantics_tester.dart';
 
 // On web, the context menu (aka toolbar) is provided by the browser.
 final bool isContextMenuProvidedByPlatform = isBrowser;
 
-class MockClipboard {
-  Object _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments! as Object;
-        break;
-    }
-  }
-}
-
 class MockTextSelectionControls extends TextSelectionControls {
   @override
   Widget buildHandle(BuildContext context, TextSelectionHandleType type, double textLineHeight, [VoidCallback? onTap, double? startGlyphHeight, double? endGlyphHeight]) {

packages/flutter/test/cupertino/text_selection_test.dart

@@ -11,24 +11,9 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../widgets/clipboard_utils.dart';
 import '../widgets/editable_text_utils.dart' show textOffsetToPosition, findRenderEditable;
 
-class MockClipboard {
-  Object _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments! as Object;
-        break;
-    }
-  }
-}
-
 class _LongCupertinoLocalizationsDelegate extends LocalizationsDelegate<CupertinoLocalizations> {
   const _LongCupertinoLocalizationsDelegate();
 
@@ -69,7 +54,6 @@ const _LongCupertinoLocalizations _longLocalizations = _LongCupertinoLocalizatio
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
   final MockClipboard mockClipboard = MockClipboard();
-  TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, mockClipboard.handleMethodCall);
 
   // Returns true iff the button is visually enabled.
   bool appearsEnabled(WidgetTester tester, String text) {
@@ -92,6 +76,23 @@ void main() {
     }).toList();
   }
 
+  setUp(() async {
+    TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(
+      SystemChannels.platform,
+      mockClipboard.handleMethodCall,
+    );
+    // Fill the clipboard so that the Paste option is available in the text
+    // selection menu.
+    await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
+  });
+
+  tearDown(() {
+    TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(
+      SystemChannels.platform,
+      null,
+    );
+  });
+
   group('canSelectAll', () {
     Widget createEditableText({
       Key? key,
@@ -185,76 +186,6 @@ void main() {
     });
   });
 
-  // TODO(justinmc): https://github.com/flutter/flutter/issues/60145
-  testWidgets('Paste always appears regardless of clipboard content on iOS', (WidgetTester tester) async {
-    final TextEditingController controller = TextEditingController(
-      text: 'Atwater Peel Sherbrooke Bonaventure',
-    );
-    await tester.pumpWidget(
-      CupertinoApp(
-        home: Column(
-          children: <Widget>[
-            CupertinoTextField(
-              controller: controller,
-            ),
-          ],
-        ),
-      ),
-    );
-
-    // Make sure the clipboard is empty to start.
-    await Clipboard.setData(const ClipboardData(text: ''));
-
-    // Double tap to select the first word.
-    const int index = 4;
-    await tester.tapAt(textOffsetToPosition(tester, index));
-    await tester.pump(const Duration(milliseconds: 50));
-    await tester.tapAt(textOffsetToPosition(tester, index));
-    await tester.pumpAndSettle();
-    expect(controller.selection.isCollapsed, isFalse);
-    expect(controller.selection.baseOffset, 0);
-    expect(controller.selection.extentOffset, 7);
-
-    // Paste is showing even though clipboard is empty.
-    expect(find.text('Paste'), findsOneWidget);
-    expect(find.text('Copy'), findsOneWidget);
-    expect(find.text('Cut'), findsOneWidget);
-    expect(find.descendant(
-      of: find.byType(Overlay),
-      matching: find.byWidgetPredicate((Widget w) => '${w.runtimeType}' == '_TextSelectionHandleOverlay'),
-    ), findsNWidgets(2));
-
-    // Tap copy to add something to the clipboard and close the menu.
-    await tester.tapAt(tester.getCenter(find.text('Copy')));
-    await tester.pumpAndSettle();
-
-    // The menu is gone, but the handles are visible on the existing selection.
-    expect(find.text('Copy'), findsNothing);
-    expect(find.text('Cut'), findsNothing);
-    expect(find.text('Paste'), findsNothing);
-    expect(controller.selection.isCollapsed, isFalse);
-    expect(controller.selection.baseOffset, 0);
-    expect(controller.selection.extentOffset, 7);
-    expect(find.descendant(
-      of: find.byType(Overlay),
-      matching: find.byWidgetPredicate((Widget w) => '${w.runtimeType}' == '_TextSelectionHandleOverlay'),
-    ), findsNWidgets(2));
-
-    // Double tap to show the menu again.
-    await tester.tapAt(textOffsetToPosition(tester, index));
-    await tester.pump(const Duration(milliseconds: 50));
-    await tester.tapAt(textOffsetToPosition(tester, index));
-    await tester.pumpAndSettle();
-
-    // Paste still shows.
-    expect(find.text('Paste'), findsOneWidget);
-    expect(find.text('Copy'), findsOneWidget);
-    expect(find.text('Cut'), findsOneWidget);
-  },
-    skip: isBrowser, // [intended] We do not use Flutter-rendered context menu on the Web.
-    variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS }),
-  );
-
   group('Text selection menu overflow (iOS)', () {
     testWidgets('All menu items show when they fit.', (WidgetTester tester) async {
       final TextEditingController controller = TextEditingController(text: 'abc def ghi');

packages/flutter/test/material/input_date_picker_form_field_test.dart

@@ -6,6 +6,8 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../widgets/clipboard_utils.dart';
+
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
   final MockClipboard mockClipboard = MockClipboard();
@@ -301,19 +303,3 @@ void main() {
 
   });
 }
-
-class MockClipboard {
-  dynamic _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments;
-        break;
-    }
-  }
-}

packages/flutter/test/material/search_test.dart

@@ -7,24 +7,9 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../widgets/clipboard_utils.dart';
 import '../widgets/semantics_tester.dart';
 
-class MockClipboard {
-  dynamic _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments;
-        break;
-    }
-  }
-}
-
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
   final MockClipboard mockClipboard = MockClipboard();

packages/flutter/test/material/text_field_test.dart

@@ -19,6 +19,7 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../widgets/clipboard_utils.dart';
 import '../widgets/editable_text_utils.dart' show findRenderEditable, globalize, textOffsetToPosition;
 import '../widgets/semantics_tester.dart';
 import 'feedback_tester.dart';
@@ -31,22 +32,6 @@ final bool isContextMenuProvidedByPlatform = isBrowser;
 // On web, key events in text fields are handled by the browser.
 final bool areKeyEventsHandledByPlatform = isBrowser;
 
-class MockClipboard {
-  Object _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments as Object;
-        break;
-    }
-  }
-}
-
 class MaterialLocalizationsDelegate extends LocalizationsDelegate<MaterialLocalizations> {
   @override
   bool isSupported(Locale locale) => true;
@@ -6220,8 +6205,8 @@ void main() {
 
     semantics.dispose();
 
-    // On web (just like iOS), we don't check for pasteability because that
-    // triggers a permission dialog in the browser.
+    // On web, we don't check for pasteability because that triggers a
+    // permission dialog in the browser.
     // https://github.com/flutter/flutter/pull/57139#issuecomment-629048058
   }, skip: isBrowser); // [intended] see above.
 
@@ -9550,11 +9535,19 @@ void main() {
       ),
     );
 
-    bool triedToReadClipboard = false;
+    bool calledGetData = false;
+    bool calledHasStrings = false;
     tester.binding.defaultBinaryMessenger
       .setMockMethodCallHandler(SystemChannels.platform, (MethodCall methodCall) async {
-        if (methodCall.method == 'Clipboard.getData') {
-          triedToReadClipboard = true;
+        switch (methodCall.method) {
+          case 'Clipboard.getData':
+            calledGetData = true;
+            break;
+          case 'Clipboard.hasStrings':
+            calledHasStrings = true;
+            break;
+          default:
+            break;
         }
         return null;
       });
@@ -9567,14 +9560,16 @@ void main() {
     await tester.tapAt(textfieldStart + const Offset(150.0, 9.0));
     await tester.pump();
 
+    // getData is not called unless something is pasted.  hasStrings is used to
+    // check the status of the clipboard.
+    expect(calledGetData, false);
     if (kIsWeb) {
-      // The clipboard is not checked because it requires user permissions and
-      // web doesn't show a custom text selection menu.
-      expect(triedToReadClipboard, false);
+      // hasStrings is not checked because web doesn't show a custom text
+      // selection menu.
+      expect(calledHasStrings, false);
     } else {
-      // The clipboard is checked in order to decide if the content can be
-      // pasted.
-      expect(triedToReadClipboard, true);
+      // hasStrings is checked in order to decide if the content can be pasted.
+      expect(calledHasStrings, true);
     }
   });
 

packages/flutter/test/material/text_form_field_test.dart

@@ -11,24 +11,9 @@ import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../rendering/mock_canvas.dart';
+import '../widgets/clipboard_utils.dart';
 import '../widgets/editable_text_utils.dart';
 
-class MockClipboard {
-  Object _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments as Object;
-        break;
-    }
-  }
-}
-
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
   final MockClipboard mockClipboard = MockClipboard();

packages/flutter/test/material/text_selection_test.dart

@@ -7,33 +7,31 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../widgets/clipboard_utils.dart';
 import '../widgets/editable_text_utils.dart' show findRenderEditable, globalize, textOffsetToPosition;
 
-class MockClipboard {
-  Object _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments as Object;
-        break;
-    }
-  }
-}
-
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
   final MockClipboard mockClipboard = MockClipboard();
-  TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, mockClipboard.handleMethodCall);
 
   setUp(() async {
+    TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger
+        .setMockMethodCallHandler(
+          SystemChannels.platform,
+          mockClipboard.handleMethodCall,
+        );
+    // Fill the clipboard so that the Paste option is available in the text
+    // selection menu.
     await Clipboard.setData(const ClipboardData(text: 'clipboard data'));
   });
 
+  tearDown(() {
+    TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(
+      SystemChannels.platform,
+      null,
+    );
+  });
+
   group('canSelectAll', () {
     Widget createEditableText({
       required Key key,
@@ -671,59 +669,4 @@ void main() {
     skip: isBrowser, // [intended] we don't supply the cut/copy/paste buttons on the web.
     variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.android })
   );
-
-  // TODO(justinmc): https://github.com/flutter/flutter/issues/60145
-  testWidgets('Paste always appears regardless of clipboard content on iOS', (WidgetTester tester) async {
-    final TextEditingController controller = TextEditingController(
-      text: 'Atwater Peel Sherbrooke Bonaventure',
-    );
-    await tester.pumpWidget(
-      MaterialApp(
-        home: Material(
-          child: Column(
-            children: <Widget>[
-              TextField(
-                controller: controller,
-              ),
-            ],
-          ),
-        ),
-      ),
-    );
-
-    // Make sure the clipboard is empty.
-    await Clipboard.setData(const ClipboardData(text: ''));
-
-    // Double tap to select the first word.
-    const int index = 4;
-    await tester.tapAt(textOffsetToPosition(tester, index));
-    await tester.pump(const Duration(milliseconds: 50));
-    await tester.tapAt(textOffsetToPosition(tester, index));
-    await tester.pumpAndSettle();
-
-    // Paste is showing even though clipboard is empty.
-    expect(find.text('Paste'), findsOneWidget);
-    expect(find.text('Copy'), findsOneWidget);
-    expect(find.text('Cut'), findsOneWidget);
-
-    // Tap copy to add something to the clipboard and close the menu.
-    await tester.tapAt(tester.getCenter(find.text('Copy')));
-    await tester.pumpAndSettle();
-    expect(find.text('Copy'), findsNothing);
-    expect(find.text('Cut'), findsNothing);
-
-    // Double tap to show the menu again.
-    await tester.tapAt(textOffsetToPosition(tester, index));
-    await tester.pump(const Duration(milliseconds: 50));
-    await tester.tapAt(textOffsetToPosition(tester, index));
-    await tester.pumpAndSettle();
-
-    // Paste still shows.
-    expect(find.text('Copy'), findsOneWidget);
-    expect(find.text('Cut'), findsOneWidget);
-    expect(find.text('Paste'), findsOneWidget);
-  },
-    skip: isBrowser, // [intended] we don't supply the cut/copy/paste buttons on the web.
-    variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS })
-  );
 }

packages/flutter/test/widgets/clipboard_utils.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/services.dart';
+
+class MockClipboard {
+  MockClipboard({
+    this.hasStringsThrows = false,
+  });
+
+  final bool hasStringsThrows;
+
+  dynamic _clipboardData = <String, dynamic>{
+    'text': null,
+  };
+
+  Future<Object?> handleMethodCall(MethodCall methodCall) async {
+    switch (methodCall.method) {
+      case 'Clipboard.getData':
+        return _clipboardData;
+      case 'Clipboard.hasStrings':
+        if (hasStringsThrows)
+          throw Exception();
+        final Map<String, dynamic>? clipboardDataMap = _clipboardData as Map<String, dynamic>?;
+        final String? text = clipboardDataMap?['text'] as String?;
+        return <String, bool>{'value': text != null && text.isNotEmpty};
+      case 'Clipboard.setData':
+        _clipboardData = methodCall.arguments;
+        break;
+    }
+  }
+}

packages/flutter/test/widgets/editable_text_cursor_test.dart

@@ -82,6 +82,8 @@ void main() {
     tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, (MethodCall methodCall) async {
       if (methodCall.method == 'Clipboard.getData')
         return const <String, dynamic>{'text': clipboardContent};
+      if (methodCall.method == 'Clipboard.hasStrings')
+        return <String, dynamic>{'value': clipboardContent.isNotEmpty};
       return null;
     });
 
@@ -134,6 +136,8 @@ void main() {
     tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, (MethodCall methodCall) async {
       if (methodCall.method == 'Clipboard.getData')
         return const <String, dynamic>{'text': clipboardContent};
+      if (methodCall.method == 'Clipboard.hasStrings')
+        return <String, dynamic>{'value': clipboardContent.isNotEmpty};
       return null;
     });
 
@@ -860,6 +864,8 @@ void main() {
     tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, (MethodCall methodCall) async {
       if (methodCall.method == 'Clipboard.getData')
         return const <String, dynamic>{'text': clipboardContent};
+      if (methodCall.method == 'Clipboard.hasStrings')
+        return <String, dynamic>{'value': clipboardContent.isNotEmpty};
       return null;
     });
 
@@ -918,6 +924,8 @@ void main() {
     tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, (MethodCall methodCall) async {
       if (methodCall.method == 'Clipboard.getData')
         return const <String, dynamic>{'text': clipboardContent};
+      if (methodCall.method == 'Clipboard.hasStrings')
+        return <String, dynamic>{'value': clipboardContent.isNotEmpty};
       return null;
     });
 

packages/flutter/test/widgets/editable_text_test.dart

@@ -11,6 +11,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../rendering/mock_canvas.dart';
+import '../widgets/clipboard_utils.dart';
 import 'editable_text_utils.dart';
 import 'semantics_tester.dart';
 
@@ -48,22 +49,6 @@ enum HandlePositionInViewport {
   leftEdge, rightEdge, within,
 }
 
-class MockClipboard {
-  Object _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments as Object;
-        break;
-    }
-  }
-}
-
 void main() {
   final MockClipboard mockClipboard = MockClipboard();
   (TestWidgetsFlutterBinding.ensureInitialized() as TestWidgetsFlutterBinding)
@@ -1336,6 +1321,56 @@ void main() {
     expect(find.text('Paste'), kIsWeb ? findsNothing : findsOneWidget);
   });
 
+  testWidgets('Paste is shown only when there is something to paste', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: EditableText(
+          backgroundCursorColor: Colors.grey,
+          controller: controller,
+          focusNode: focusNode,
+          style: textStyle,
+          cursorColor: cursorColor,
+          selectionControls: materialTextSelectionControls,
+        ),
+      ),
+    );
+
+    final EditableTextState state =
+        tester.state<EditableTextState>(find.byType(EditableText));
+
+    // Make sure the clipboard has a valid string on it.
+    await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
+
+    // Show the toolbar.
+    state.renderEditable.selectWordsInRange(
+      from: Offset.zero,
+      cause: SelectionChangedCause.tap,
+    );
+    await tester.pump();
+
+    // The Paste button is shown (except on web, which doesn't show the Flutter
+    // toolbar).
+    expect(state.showToolbar(), kIsWeb ? isFalse : isTrue);
+    await tester.pumpAndSettle();
+    expect(find.text('Paste'), kIsWeb ? findsNothing : findsOneWidget);
+
+    // Hide the menu again.
+    state.hideToolbar();
+    await tester.pump();
+    expect(find.text('Paste'), findsNothing);
+
+    // Clear the clipboard
+    await Clipboard.setData(const ClipboardData(text: ''));
+
+    // Show the toolbar again.
+    expect(state.showToolbar(), kIsWeb ? isFalse : isTrue);
+    await tester.pumpAndSettle();
+
+    // Paste is not shown.
+    await tester.pumpAndSettle();
+    expect(find.text('Paste'), findsNothing);
+  });
+
   testWidgets('can show the toolbar after clearing all text', (WidgetTester tester) async {
     // Regression test for https://github.com/flutter/flutter/issues/35998.
     await tester.pumpWidget(

packages/flutter/test/widgets/selectable_text_test.dart

@@ -13,25 +13,10 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../widgets/clipboard_utils.dart';
 import '../widgets/editable_text_utils.dart' show textOffsetToPosition;
 import '../widgets/semantics_tester.dart';
 
-class MockClipboard {
-  dynamic _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<dynamic> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments;
-        break;
-    }
-  }
-}
-
 class MaterialLocalizationsDelegate extends LocalizationsDelegate<MaterialLocalizations> {
   @override
   bool isSupported(Locale locale) => true;
@@ -126,7 +111,6 @@ double getOpacity(WidgetTester tester, Finder finder) {
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
   final MockClipboard mockClipboard = MockClipboard();
-  TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, mockClipboard.handleMethodCall);
 
   const String kThreeLines =
       'First line of text is\n'
@@ -165,11 +149,22 @@ void main() {
 
   setUp(() async {
     debugResetSemanticsIdCounter();
+    TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(
+      SystemChannels.platform,
+      mockClipboard.handleMethodCall,
+    );
     // Fill the clipboard so that the Paste option is available in the text
     // selection menu.
     await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
   });
 
+  tearDown(() {
+    TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(
+      SystemChannels.platform,
+      null,
+    );
+  });
+
   Widget selectableTextBuilder({
     String text = '',
     int? maxLines = 1,

packages/flutter/test/widgets/text_selection_test.dart

@@ -8,29 +8,7 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-class MockClipboard {
-  MockClipboard({
-    this.getDataThrows = false,
-  });
-
-  final bool getDataThrows;
-
-  dynamic _clipboardData = <String, dynamic>{
-    'text': null,
-  };
-
-  Future<Object?> handleMethodCall(MethodCall methodCall) async {
-    switch (methodCall.method) {
-      case 'Clipboard.getData':
-        if (getDataThrows)
-          throw Exception();
-        return _clipboardData;
-      case 'Clipboard.setData':
-        _clipboardData = methodCall.arguments;
-        break;
-    }
-  }
-}
+import 'clipboard_utils.dart';
 
 void main() {
   late int tapCount;
@@ -757,7 +735,7 @@ void main() {
   group('ClipboardStatusNotifier', () {
     group('when Clipboard fails', () {
       setUp(() {
-        final MockClipboard mockClipboard = MockClipboard(getDataThrows: true);
+        final MockClipboard mockClipboard = MockClipboard(hasStringsThrows: true);
         TestDefaultBinaryMessengerBinding.instance!.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, mockClipboard.handleMethodCall);
       });