Bring back paste button hide behavior (#56689)

Unreverts #54902 with fixes for a failing integration test.

dev/integration_tests/android_semantics_testing/test_driver/main_test.dart

@@ -101,7 +101,6 @@ void main() {
             actions: <AndroidSemanticsAction>[
               AndroidSemanticsAction.clearAccessibilityFocus,
               AndroidSemanticsAction.click,
-              AndroidSemanticsAction.copy,
               AndroidSemanticsAction.setSelection,
             ],
           ),
@@ -111,6 +110,33 @@ void main() {
         // Delay for TalkBack to update focus as of November 2019 with Pixel 3 and Android API 28
         await Future<void>.delayed(const Duration(milliseconds: 500));
 
+        expect(
+          await getSemantics(normalTextField),
+          hasAndroidSemantics(
+            text: 'hello world',
+            className: AndroidClassName.editText,
+            isFocusable: true,
+            isFocused: true,
+            isEditable: true,
+            isPassword: false,
+            actions: <AndroidSemanticsAction>[
+              AndroidSemanticsAction.clearAccessibilityFocus,
+              AndroidSemanticsAction.click,
+              AndroidSemanticsAction.setSelection,
+            ],
+          ),
+        );
+
+        // Copy the text so that the clipboard contains something pasteable.
+        await driver.tap(normalTextField);
+        await Future<void>.delayed(const Duration(milliseconds: 50));
+        await driver.tap(normalTextField);
+        await Future<void>.delayed(const Duration(milliseconds: 500));
+        await driver.tap(find.text('SELECT ALL'));
+        await Future<void>.delayed(const Duration(milliseconds: 500));
+        await driver.tap(find.text('COPY'));
+        await Future<void>.delayed(const Duration(milliseconds: 50));
+
         expect(
           await getSemantics(normalTextField),
           hasAndroidSemantics(
@@ -124,6 +150,7 @@ void main() {
               AndroidSemanticsAction.clearAccessibilityFocus,
               AndroidSemanticsAction.click,
               AndroidSemanticsAction.copy,
+              AndroidSemanticsAction.nextAtMovementGranularity,
               AndroidSemanticsAction.setSelection,
             ],
           ),
@@ -166,7 +193,6 @@ void main() {
             actions: <AndroidSemanticsAction>[
               AndroidSemanticsAction.clearAccessibilityFocus,
               AndroidSemanticsAction.click,
-              AndroidSemanticsAction.copy,
               AndroidSemanticsAction.setSelection,
             ],
           ),
@@ -188,7 +214,6 @@ void main() {
             actions: <AndroidSemanticsAction>[
               AndroidSemanticsAction.clearAccessibilityFocus,
               AndroidSemanticsAction.click,
-              AndroidSemanticsAction.copy,
               AndroidSemanticsAction.setSelection,
             ],
           ),

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

@@ -8,6 +8,7 @@ import 'dart:ui' as ui;
 
 import 'package:flutter/widgets.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
 
 import 'button.dart';
 import 'colors.dart';
@@ -62,6 +63,151 @@ const TextStyle _kToolbarButtonDisabledFontStyle = TextStyle(
 // Eyeballed value.
 const EdgeInsets _kToolbarButtonPadding = EdgeInsets.symmetric(vertical: 10.0, horizontal: 18.0);
 
+// Generates the child that's passed into CupertinoTextSelectionToolbar.
+class _CupertinoTextSelectionToolbarWrapper extends StatefulWidget {
+  const _CupertinoTextSelectionToolbarWrapper({
+    Key key,
+    this.arrowTipX,
+    this.barTopY,
+    this.clipboardStatus,
+    this.handleCut,
+    this.handleCopy,
+    this.handlePaste,
+    this.handleSelectAll,
+    this.isArrowPointingDown,
+  }) : super(key: key);
+
+  final double arrowTipX;
+  final double barTopY;
+  final ClipboardStatusNotifier clipboardStatus;
+  final VoidCallback handleCut;
+  final VoidCallback handleCopy;
+  final VoidCallback handlePaste;
+  final VoidCallback handleSelectAll;
+  final bool isArrowPointingDown;
+
+  @override
+  _CupertinoTextSelectionToolbarWrapperState createState() => _CupertinoTextSelectionToolbarWrapperState();
+}
+
+class _CupertinoTextSelectionToolbarWrapperState extends State<_CupertinoTextSelectionToolbarWrapper> {
+  ClipboardStatusNotifier _clipboardStatus;
+
+  void _onChangedClipboardStatus() {
+    setState(() {
+      // Inform the widget that the value of clipboardStatus has changed.
+    });
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    _clipboardStatus = widget.clipboardStatus ?? ClipboardStatusNotifier();
+    _clipboardStatus.addListener(_onChangedClipboardStatus);
+    _clipboardStatus.update();
+  }
+
+  @override
+  void didUpdateWidget(_CupertinoTextSelectionToolbarWrapper oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.clipboardStatus == null && widget.clipboardStatus != null) {
+      _clipboardStatus.removeListener(_onChangedClipboardStatus);
+      _clipboardStatus.dispose();
+      _clipboardStatus = widget.clipboardStatus;
+    } else if (oldWidget.clipboardStatus != null) {
+      if (widget.clipboardStatus == null) {
+        _clipboardStatus = ClipboardStatusNotifier();
+        _clipboardStatus.addListener(_onChangedClipboardStatus);
+        oldWidget.clipboardStatus.removeListener(_onChangedClipboardStatus);
+      } else if (widget.clipboardStatus != oldWidget.clipboardStatus) {
+        _clipboardStatus = widget.clipboardStatus;
+        _clipboardStatus.addListener(_onChangedClipboardStatus);
+        oldWidget.clipboardStatus.removeListener(_onChangedClipboardStatus);
+      }
+    }
+    if (widget.handlePaste != null) {
+      _clipboardStatus.update();
+    }
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    // When used in an Overlay, this can be disposed after its creator has
+    // already disposed _clipboardStatus.
+    if (!_clipboardStatus.disposed) {
+      _clipboardStatus.removeListener(_onChangedClipboardStatus);
+      if (widget.clipboardStatus == null) {
+        _clipboardStatus.dispose();
+      }
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    // Don't render the menu until the state of the clipboard is known.
+    if (widget.handlePaste != null
+        && _clipboardStatus.value == ClipboardStatus.unknown) {
+      return const SizedBox(width: 0.0, height: 0.0);
+    }
+
+    final List<Widget> items = <Widget>[];
+    final CupertinoLocalizations localizations = CupertinoLocalizations.of(context);
+    final EdgeInsets arrowPadding = widget.isArrowPointingDown
+      ? EdgeInsets.only(bottom: _kToolbarArrowSize.height)
+      : EdgeInsets.only(top: _kToolbarArrowSize.height);
+    final Widget onePhysicalPixelVerticalDivider =
+        SizedBox(width: 1.0 / MediaQuery.of(context).devicePixelRatio);
+
+    void addToolbarButton(
+      String text,
+      VoidCallback onPressed,
+    ) {
+      if (items.isNotEmpty) {
+        items.add(onePhysicalPixelVerticalDivider);
+      }
+
+      items.add(CupertinoButton(
+        child: Text(
+          text,
+          overflow: TextOverflow.ellipsis,
+          style: _kToolbarButtonFontStyle,
+        ),
+        borderRadius: null,
+        color: _kToolbarBackgroundColor,
+        minSize: _kToolbarHeight,
+        onPressed: onPressed,
+        padding: _kToolbarButtonPadding.add(arrowPadding),
+        pressedOpacity: 0.7,
+      ));
+    }
+
+    if (widget.handleCut != null) {
+      addToolbarButton(localizations.cutButtonLabel, widget.handleCut);
+    }
+    if (widget.handleCopy != null) {
+      addToolbarButton(localizations.copyButtonLabel, widget.handleCopy);
+    }
+    if (widget.handlePaste != null
+        && _clipboardStatus.value == ClipboardStatus.pasteable) {
+      addToolbarButton(localizations.pasteButtonLabel, widget.handlePaste);
+    }
+    if (widget.handleSelectAll != null) {
+      addToolbarButton(localizations.selectAllButtonLabel, widget.handleSelectAll);
+    }
+
+    return CupertinoTextSelectionToolbar._(
+      barTopY: widget.barTopY,
+      arrowTipX: widget.arrowTipX,
+      isArrowPointingDown: widget.isArrowPointingDown,
+      child: items.isEmpty ? null : _CupertinoTextSelectionToolbarContent(
+        isArrowPointingDown: widget.isArrowPointingDown,
+        children: items,
+      ),
+    );
+  }
+}
+
 /// An iOS-style toolbar that appears in response to text selection.
 ///
 /// Typically displays buttons for text manipulation, e.g. copying and pasting text.
@@ -312,6 +458,7 @@ class _CupertinoTextSelectionControls extends TextSelectionControls {
     Offset position,
     List<TextSelectionPoint> endpoints,
     TextSelectionDelegate delegate,
+    ClipboardStatusNotifier clipboardStatus,
   ) {
     assert(debugCheckHasMediaQuery(context));
     final MediaQueryData mediaQuery = MediaQuery.of(context);
@@ -338,49 +485,15 @@ class _CupertinoTextSelectionControls extends TextSelectionControls {
       ? endpoints.first.point.dy - textLineHeight - _kToolbarContentDistance - _kToolbarHeight
       : endpoints.last.point.dy + _kToolbarContentDistance;
 
-    final List<Widget> items = <Widget>[];
+    return _CupertinoTextSelectionToolbarWrapper(
-    final CupertinoLocalizations localizations = CupertinoLocalizations.of(context);
-    final EdgeInsets arrowPadding = isArrowPointingDown
-      ? EdgeInsets.only(bottom: _kToolbarArrowSize.height)
-      : EdgeInsets.only(top: _kToolbarArrowSize.height);
-
-    void addToolbarButtonIfNeeded(
-      String text,
-      bool Function(TextSelectionDelegate) predicate,
-      void Function(TextSelectionDelegate) onPressed,
-    ) {
-      if (!predicate(delegate)) {
-        return;
-      }
-
-      items.add(CupertinoButton(
-        child: Text(
-          text,
-          overflow: TextOverflow.ellipsis,
-          style: _kToolbarButtonFontStyle,
-        ),
-        color: _kToolbarBackgroundColor,
-        minSize: _kToolbarHeight,
-        padding: _kToolbarButtonPadding.add(arrowPadding),
-        borderRadius: null,
-        pressedOpacity: 0.7,
-        onPressed: () => onPressed(delegate),
-      ));
-    }
-
-    addToolbarButtonIfNeeded(localizations.cutButtonLabel, canCut, handleCut);
-    addToolbarButtonIfNeeded(localizations.copyButtonLabel, canCopy, handleCopy);
-    addToolbarButtonIfNeeded(localizations.pasteButtonLabel, canPaste, handlePaste);
-    addToolbarButtonIfNeeded(localizations.selectAllButtonLabel, canSelectAll, handleSelectAll);
-
-    return CupertinoTextSelectionToolbar._(
-      barTopY: localBarTopY + globalEditableRegion.top,
       arrowTipX: arrowTipX,
+      barTopY: localBarTopY + globalEditableRegion.top,
+      clipboardStatus: clipboardStatus,
+      handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
+      handleCopy: canCopy(delegate) ? () => handleCopy(delegate, clipboardStatus) : null,
+      handlePaste: canPaste(delegate) ? () => handlePaste(delegate) : null,
+      handleSelectAll: canSelectAll(delegate) ? () => handleSelectAll(delegate) : null,
       isArrowPointingDown: isArrowPointingDown,
-      child: items.isEmpty ? null : _CupertinoTextSelectionToolbarContent(
-        isArrowPointingDown: isArrowPointingDown,
-        children: items,
-      ),
     );
   }
 

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

@@ -6,6 +6,7 @@ import 'dart:math' as math;
 
 import 'package:flutter/rendering.dart';
 import 'package:flutter/scheduler.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 
 import 'debug.dart';
@@ -29,6 +30,7 @@ const double _kToolbarContentDistance = 8.0;
 /// Manages a copy/paste text selection toolbar.
 class _TextSelectionToolbar extends StatefulWidget {
   const _TextSelectionToolbar({
+    this.clipboardStatus,
     Key key,
     this.handleCut,
     this.handleCopy,
@@ -37,6 +39,7 @@ class _TextSelectionToolbar extends StatefulWidget {
     this.isAbove,
   }) : super(key: key);
 
+  final ClipboardStatusNotifier clipboardStatus;
   final VoidCallback handleCut;
   final VoidCallback handleCopy;
   final VoidCallback handlePaste;
@@ -50,6 +53,8 @@ class _TextSelectionToolbar extends StatefulWidget {
 }
 
 class _TextSelectionToolbarState extends State<_TextSelectionToolbar> with TickerProviderStateMixin {
+  ClipboardStatusNotifier _clipboardStatus;
+
   // Whether or not the overflow menu is open. When it is closed, the menu
   // items that don't overflow are shown. When it is open, only the overflowing
   // menu items are shown.
@@ -66,12 +71,10 @@ class _TextSelectionToolbarState extends State<_TextSelectionToolbar> with Ticke
     );
   }
 
-  @override
+  // Close the menu and reset layout calculations, as in when the menu has
-  void didUpdateWidget(_TextSelectionToolbar oldWidget) {
+  // changed and saved values are no longer relevant. This should be called in
-    if (((widget.handleCut == null) != (oldWidget.handleCut == null))
+  // setState or another context where a rebuild is happening.
-      || ((widget.handleCopy == null) != (oldWidget.handleCopy == null))
+  void _reset() {
-      || ((widget.handlePaste == null) != (oldWidget.handlePaste == null))
-      || ((widget.handleSelectAll == null) != (oldWidget.handleSelectAll == null))) {
     // Change _TextSelectionToolbarContainer's key when the menu changes in
     // order to cause it to rebuild. This lets it recalculate its
     // saved width for the new set of children, and it prevents AnimatedSize
@@ -81,18 +84,80 @@ class _TextSelectionToolbarState extends State<_TextSelectionToolbar> with Ticke
     // prevents an empty overflow menu.
     _overflowOpen = false;
   }
+
+  void _onChangedClipboardStatus() {
+    setState(() {
+      // Inform the widget that the value of clipboardStatus has changed.
+    });
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    _clipboardStatus = widget.clipboardStatus ?? ClipboardStatusNotifier();
+    _clipboardStatus.addListener(_onChangedClipboardStatus);
+    _clipboardStatus.update();
+  }
+
+  @override
+  void didUpdateWidget(_TextSelectionToolbar oldWidget) {
     super.didUpdateWidget(oldWidget);
+    // If the children are changing, the current page should be reset.
+    if (((widget.handleCut == null) != (oldWidget.handleCut == null))
+      || ((widget.handleCopy == null) != (oldWidget.handleCopy == null))
+      || ((widget.handlePaste == null) != (oldWidget.handlePaste == null))
+      || ((widget.handleSelectAll == null) != (oldWidget.handleSelectAll == null))) {
+      _reset();
+    }
+    if (oldWidget.clipboardStatus == null && widget.clipboardStatus != null) {
+      _clipboardStatus.removeListener(_onChangedClipboardStatus);
+      _clipboardStatus.dispose();
+      _clipboardStatus = widget.clipboardStatus;
+    } else if (oldWidget.clipboardStatus != null) {
+      if (widget.clipboardStatus == null) {
+        _clipboardStatus = ClipboardStatusNotifier();
+        _clipboardStatus.addListener(_onChangedClipboardStatus);
+        oldWidget.clipboardStatus.removeListener(_onChangedClipboardStatus);
+      } else if (widget.clipboardStatus != oldWidget.clipboardStatus) {
+        _clipboardStatus = widget.clipboardStatus;
+        _clipboardStatus.addListener(_onChangedClipboardStatus);
+        oldWidget.clipboardStatus.removeListener(_onChangedClipboardStatus);
+      }
+    }
+    if (widget.handlePaste != null) {
+      _clipboardStatus.update();
+    }
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    // When used in an Overlay, this can be disposed after its creator has
+    // already disposed _clipboardStatus.
+    if (!_clipboardStatus.disposed) {
+      _clipboardStatus.removeListener(_onChangedClipboardStatus);
+      if (widget.clipboardStatus == null) {
+        _clipboardStatus.dispose();
+      }
+    }
   }
 
   @override
   Widget build(BuildContext context) {
+    // Don't render the menu until the state of the clipboard is known.
+    if (widget.handlePaste != null
+        && _clipboardStatus.value == ClipboardStatus.unknown) {
+      return const SizedBox(width: 0.0, height: 0.0);
+    }
+
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
     final List<Widget> items = <Widget>[
       if (widget.handleCut != null)
         _getItem(widget.handleCut, localizations.cutButtonLabel),
       if (widget.handleCopy != null)
         _getItem(widget.handleCopy, localizations.copyButtonLabel),
-      if (widget.handlePaste != null)
+      if (widget.handlePaste != null
+          && _clipboardStatus.value == ClipboardStatus.pasteable)
         _getItem(widget.handlePaste, localizations.pasteButtonLabel),
       if (widget.handleSelectAll != null)
         _getItem(widget.handleSelectAll, localizations.selectAllButtonLabel),
@@ -103,7 +168,6 @@ class _TextSelectionToolbarState extends State<_TextSelectionToolbar> with Ticke
       return const SizedBox(width: 0.0, height: 0.0);
     }
 
-
     return _TextSelectionToolbarContainer(
       key: _containerKey,
       overflowOpen: _overflowOpen,
@@ -527,6 +591,18 @@ class _TextSelectionToolbarItemsRenderBox extends RenderBox with ContainerRender
     }
     return false;
   }
+
+  // Visit only the children that should be painted.
+  @override
+  void visitChildrenForSemantics(RenderObjectVisitor visitor) {
+    visitChildren((RenderObject renderObjectChild) {
+      final RenderBox child = renderObjectChild as RenderBox;
+      final ToolbarItemsParentData childParentData = child.parentData as ToolbarItemsParentData;
+      if (childParentData.shouldPaint) {
+        visitor(renderObjectChild);
+      }
+    });
+  }
 }
 
 /// Centers the toolbar around the given anchor, ensuring that it remains on
@@ -630,6 +706,7 @@ class _MaterialTextSelectionControls extends TextSelectionControls {
     Offset selectionMidpoint,
     List<TextSelectionPoint> endpoints,
     TextSelectionDelegate delegate,
+    ClipboardStatusNotifier clipboardStatus,
   ) {
     assert(debugCheckHasMediaQuery(context));
     assert(debugCheckHasMaterialLocalizations(context));
@@ -665,8 +742,9 @@ class _MaterialTextSelectionControls extends TextSelectionControls {
             fitsAbove,
           ),
           child: _TextSelectionToolbar(
+            clipboardStatus: clipboardStatus,
             handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
-            handleCopy: canCopy(delegate) ? () => handleCopy(delegate) : null,
+            handleCopy: canCopy(delegate) ? () => handleCopy(delegate, clipboardStatus) : null,
             handlePaste: canPaste(delegate) ? () => handlePaste(delegate) : null,
             handleSelectAll: canSelectAll(delegate) ? () => handleSelectAll(delegate) : null,
             isAbove: fitsAbove,

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

@@ -1144,6 +1144,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   bool _targetCursorVisibility = false;
   final ValueNotifier<bool> _cursorVisibilityNotifier = ValueNotifier<bool>(true);
   final GlobalKey _editableKey = GlobalKey();
+  final ClipboardStatusNotifier _clipboardStatus = ClipboardStatusNotifier();
 
   TextInputConnection _textInputConnection;
   TextSelectionOverlay _selectionOverlay;
@@ -1190,11 +1191,18 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   @override
   bool get selectAllEnabled => widget.toolbarOptions.selectAll;
 
+  void _onChangedClipboardStatus() {
+    setState(() {
+      // Inform the widget that the value of clipboardStatus has changed.
+    });
+  }
+
   // State lifecycle:
 
   @override
   void initState() {
     super.initState();
+    _clipboardStatus.addListener(_onChangedClipboardStatus);
     widget.controller.addListener(_didChangeTextEditingValue);
     _focusAttachment = widget.focusNode.attach(context);
     widget.focusNode.addListener(_handleFocusChanged);
@@ -1268,6 +1276,9 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
         );
       }
     }
+    if (widget.selectionEnabled && pasteEnabled && widget.selectionControls?.canPaste(this) == true) {
+      _clipboardStatus.update();
+    }
   }
 
   @override
@@ -1284,6 +1295,9 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     _selectionOverlay = null;
     _focusAttachment.detach();
     widget.focusNode.removeListener(_handleFocusChanged);
+    WidgetsBinding.instance.removeObserver(this);
+    _clipboardStatus.removeListener(_onChangedClipboardStatus);
+    _clipboardStatus.dispose();
     super.dispose();
   }
 
@@ -1610,6 +1624,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
 
     if (widget.selectionControls != null) {
       _selectionOverlay = TextSelectionOverlay(
+        clipboardStatus: _clipboardStatus,
         context: context,
         value: _value,
         debugRequiredFor: widget,
@@ -1980,7 +1995,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
 
   VoidCallback _semanticsOnCopy(TextSelectionControls controls) {
     return widget.selectionEnabled && copyEnabled && _hasFocus && controls?.canCopy(this) == true
-      ? () => controls.handleCopy(this)
+      ? () => controls.handleCopy(this, _clipboardStatus)
       : null;
   }
 
@@ -1991,7 +2006,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   VoidCallback _semanticsOnPaste(TextSelectionControls controls) {
-    return widget.selectionEnabled && pasteEnabled &&_hasFocus && controls?.canPaste(this) == true
+    return widget.selectionEnabled && pasteEnabled && _hasFocus && controls?.canPaste(this) == true && _clipboardStatus.value == ClipboardStatus.pasteable
       ? () => controls.handlePaste(this)
       : null;
   }

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

@@ -12,6 +12,7 @@ import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 
 import 'basic.dart';
+import 'binding.dart';
 import 'constants.dart';
 import 'container.dart';
 import 'editable_text.dart';
@@ -137,6 +138,7 @@ abstract class TextSelectionControls {
     Offset position,
     List<TextSelectionPoint> endpoints,
     TextSelectionDelegate delegate,
+    ClipboardStatusNotifier clipboardStatus,
   );
 
   /// Returns the size of the selection handle.
@@ -165,13 +167,16 @@ abstract class TextSelectionControls {
     return delegate.copyEnabled && !delegate.textEditingValue.selection.isCollapsed;
   }
 
-  /// Whether the current [Clipboard] content can be pasted into the text field
+  /// Whether the text field managed by the given `delegate` supports pasting
-  /// managed by the given `delegate`.
+  /// from the clipboard.
   ///
   /// Subclasses can use this to decide if they should expose the paste
   /// functionality to the user.
+  ///
+  /// This does not consider the contents of the clipboard. Subclasses may want
+  /// to, for example, disallow pasting when the clipboard contains an empty
+  /// string.
   bool canPaste(TextSelectionDelegate delegate) {
-    // TODO(goderbauer): return false when clipboard is empty, https://github.com/flutter/flutter/issues/11254
     return delegate.pasteEnabled;
   }
 
@@ -213,11 +218,12 @@ abstract class TextSelectionControls {
   ///
   /// This is called by subclasses when their copy affordance is activated by
   /// the user.
-  void handleCopy(TextSelectionDelegate delegate) {
+  void handleCopy(TextSelectionDelegate delegate, ClipboardStatusNotifier clipboardStatus) {
     final TextEditingValue value = delegate.textEditingValue;
     Clipboard.setData(ClipboardData(
       text: value.selection.textInside(value.text),
     ));
+    clipboardStatus?.update();
     delegate.textEditingValue = TextEditingValue(
       text: value.text,
       selection: TextSelection.collapsed(offset: value.selection.end),
@@ -294,6 +300,7 @@ class TextSelectionOverlay {
     this.selectionDelegate,
     this.dragStartBehavior = DragStartBehavior.start,
     this.onSelectionHandleTapped,
+    this.clipboardStatus,
   }) : assert(value != null),
        assert(context != null),
        assert(handlesVisible != null),
@@ -365,6 +372,13 @@ class TextSelectionOverlay {
   /// {@endtemplate}
   final VoidCallback onSelectionHandleTapped;
 
+  /// Maintains the status of the clipboard for determining if its contents can
+  /// be pasted or not.
+  ///
+  /// Useful because the actual value of the clipboard can only be checked
+  /// asynchronously (see [Clipboard.getData]).
+  final ClipboardStatusNotifier clipboardStatus;
+
   /// Controls the fade-in and fade-out animations for the toolbar and handles.
   static const Duration fadeDuration = Duration(milliseconds: 150);
 
@@ -576,6 +590,7 @@ class TextSelectionOverlay {
           midpoint,
           endpoints,
           selectionDelegate,
+          clipboardStatus,
         ),
       ),
     );
@@ -1486,3 +1501,86 @@ class _TransparentTapGestureRecognizer extends TapGestureRecognizer {
     }
   }
 }
+
+/// A [ValueNotifier] whose [value] indicates whether the current contents of
+/// the clipboard can be pasted.
+///
+/// The contents of the clipboard can only be read asynchronously, via
+/// [Clipboard.getData], so this maintains a value that can be used
+/// synchronously. Call [update] to asynchronously update value if needed.
+class ClipboardStatusNotifier extends ValueNotifier<ClipboardStatus> with WidgetsBindingObserver {
+  /// Create a new ClipboardStatusNotifier.
+  ClipboardStatusNotifier({
+    ClipboardStatus value = ClipboardStatus.unknown,
+  }) : super(value);
+
+  bool _disposed = false;
+  /// True iff this instance has been disposed.
+  bool get disposed => _disposed;
+
+  /// Check the [Clipboard] and update [value] if needed.
+  void update() {
+    Clipboard.getData(Clipboard.kTextPlain).then((ClipboardData data) {
+      final ClipboardStatus clipboardStatus = data != null && data.text != null && data.text.isNotEmpty
+          ? ClipboardStatus.pasteable
+          : ClipboardStatus.notPasteable;
+      if (clipboardStatus == value) {
+        return;
+      }
+      value = clipboardStatus;
+    });
+  }
+
+  @override
+  void addListener(VoidCallback listener) {
+    if (!hasListeners) {
+      WidgetsBinding.instance.addObserver(this);
+    }
+    if (value == ClipboardStatus.unknown) {
+      update();
+    }
+    super.addListener(listener);
+  }
+
+  @override
+  void removeListener(VoidCallback listener) {
+    super.removeListener(listener);
+    if (!hasListeners) {
+      WidgetsBinding.instance.removeObserver(this);
+    }
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    switch (state) {
+      case AppLifecycleState.resumed:
+        update();
+        break;
+      case AppLifecycleState.detached:
+      case AppLifecycleState.inactive:
+      case AppLifecycleState.paused:
+        // Nothing to do.
+    }
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    WidgetsBinding.instance.removeObserver(this);
+    _disposed = true;
+  }
+}
+
+/// An enumeration of the status of the content on the user's clipboard.
+enum ClipboardStatus {
+  /// The clipboard content can be pasted, such as a String of nonzero length.
+  pasteable,
+
+  /// The status of the clipboard is unknown. Since getting clipboard data is
+  /// asynchronous (see [Clipboard.getData]), this status often exists while
+  /// waiting to receive the clipboard contents for the first time.
+  unknown,
+
+  /// The content on the clipboard is not pasteable, such as when it is empty.
+  notPasteable,
+}

packages/flutter/test/cupertino/text_field_test.dart

@@ -171,8 +171,11 @@ void main() {
 
   Offset textOffsetToPosition(WidgetTester tester, int offset) => textOffsetToBottomLeftPosition(tester, offset) + const Offset(0, -2);
 
-  setUp(() {
+  setUp(() async {
     EditableText.debugDeterministicCursor = false;
+    // Fill the clipboard so that the PASTE option is available in the text
+    // selection menu.
+    await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
   });
 
   testWidgets(
@@ -1545,7 +1548,7 @@ void main() {
       await tester.tapAt(textOffsetToPosition(tester, index));
       await tester.pump(const Duration(milliseconds: 50));
       await tester.tapAt(textOffsetToPosition(tester, index));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(
         controller.selection,
         const TextSelection(baseOffset: 0, extentOffset: 7),
@@ -1585,7 +1588,7 @@ void main() {
         const TextSelection.collapsed(offset: 8, affinity: TextAffinity.downstream),
       );
       await tester.tapAt(textfieldStart + const Offset(150.0, 5.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Second tap selects the word around the cursor.
       expect(
@@ -1621,7 +1624,7 @@ void main() {
       final TestGesture gesture =
          await tester.startGesture(textfieldStart + const Offset(150.0, 5.0));
       // Hold the press.
-      await tester.pump(const Duration(milliseconds: 500));
+      await tester.pumpAndSettle();
 
       expect(
         controller.selection,
@@ -1760,7 +1763,7 @@ void main() {
       final TestGesture gesture =
          await tester.startGesture(textfieldStart + const Offset(150.0, 5.0));
       // Hold the press.
-      await tester.pump(const Duration(milliseconds: 500));
+      await tester.pumpAndSettle();
 
       // The obscured text is treated as one word, should select all
       expect(
@@ -1846,7 +1849,7 @@ void main() {
       final Offset textfieldStart = tester.getTopLeft(find.byType(CupertinoTextField));
 
       await tester.longPressAt(textfieldStart + const Offset(50.0, 5.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Collapsed cursor for iOS long press.
       expect(
@@ -1946,7 +1949,7 @@ void main() {
       expect(find.byType(CupertinoButton), findsNothing);
 
       await gesture.up();
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // The selection isn't affected by the gesture lift.
       expect(
@@ -2021,7 +2024,7 @@ void main() {
     expect(find.byType(CupertinoButton), findsNothing);
 
     await gesture.up();
-    await tester.pump();
+    await tester.pumpAndSettle();
 
     // The selection isn't affected by the gesture lift.
     expect(
@@ -2076,7 +2079,7 @@ void main() {
       await tester.pump(const Duration(milliseconds: 500));
 
       await tester.longPressAt(textfieldStart + const Offset(100.0, 5.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Plain collapsed selection at the exact tap position.
       expect(
@@ -2118,7 +2121,7 @@ void main() {
         const TextSelection.collapsed(offset: 8, affinity: TextAffinity.downstream),
       );
       await tester.tapAt(textfieldStart + const Offset(150.0, 5.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Double tap selection.
       expect(
@@ -2155,7 +2158,7 @@ void main() {
         const TextSelection.collapsed(offset: 7, affinity: TextAffinity.upstream),
       );
       await tester.tapAt(textfieldStart + const Offset(50.0, 5.0));
-      await tester.pump(const Duration(milliseconds: 50));
+      await tester.pumpAndSettle();
       expect(
         controller.selection,
         const TextSelection(baseOffset: 0, extentOffset: 7),
@@ -2171,7 +2174,7 @@ void main() {
         const TextSelection.collapsed(offset: 7, affinity: TextAffinity.upstream),
       );
       await tester.tapAt(textfieldStart + const Offset(100.0, 5.0));
-      await tester.pump(const Duration(milliseconds: 50));
+      await tester.pumpAndSettle();
       expect(
         controller.selection,
         const TextSelection(baseOffset: 0, extentOffset: 7),
@@ -2186,7 +2189,7 @@ void main() {
         const TextSelection.collapsed(offset: 8, affinity: TextAffinity.downstream),
       );
       await tester.tapAt(textfieldStart + const Offset(150.0, 5.0));
-      await tester.pump(const Duration(milliseconds: 50));
+      await tester.pumpAndSettle();
       expect(
         controller.selection,
         const TextSelection(baseOffset: 8, extentOffset: 12),
@@ -2230,7 +2233,7 @@ void main() {
     );
 
     await gesture.up();
-    await tester.pump();
+    await tester.pumpAndSettle();
     // Shows toolbar.
     expect(find.byType(CupertinoButton), findsNWidgets(3));
   });
@@ -3842,7 +3845,7 @@ void main() {
 
         // Long press shows the selection menu.
         await tester.longPressAt(textOffsetToPosition(tester, 0));
-        await tester.pump();
+        await tester.pumpAndSettle();
         expect(find.text('Paste'), findsOneWidget);
       },
     );

packages/flutter/test/cupertino/text_selection_test.dart

@@ -8,9 +8,26 @@ import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import '../widgets/text.dart' show 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;
+        break;
+    }
+  }
+}
+
 class _LongCupertinoLocalizationsDelegate extends LocalizationsDelegate<CupertinoLocalizations> {
   const _LongCupertinoLocalizationsDelegate();
 
@@ -49,6 +66,9 @@ class _LongCupertinoLocalizations extends DefaultCupertinoLocalizations {
 const _LongCupertinoLocalizations longLocalizations = _LongCupertinoLocalizations();
 
 void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final MockClipboard mockClipboard = MockClipboard();
+  SystemChannels.platform.setMockMethodCallHandler(mockClipboard.handleMethodCall);
 
   // Returns true iff the button is visually enabled.
   bool appearsEnabled(WidgetTester tester, String text) {
@@ -154,6 +174,55 @@ void main() {
     });
   });
 
+  testWidgets('Paste only appears when clipboard has contents', (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 selet 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();
+
+    // No Paste yet, because nothing has been copied.
+    expect(find.text('Paste'), findsNothing);
+    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 now shows.
+    expect(find.text('Paste'), findsOneWidget);
+    expect(find.text('Copy'), findsOneWidget);
+    expect(find.text('Cut'), findsOneWidget);
+  }, skip: isBrowser, 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');
@@ -181,7 +250,7 @@ void main() {
 
       // Long press on an empty space to show the selection menu.
       await tester.longPressAt(textOffsetToPosition(tester, 4));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('Cut'), findsNothing);
       expect(find.text('Copy'), findsNothing);
       expect(find.text('Paste'), findsOneWidget);
@@ -405,7 +474,7 @@ void main() {
       // Long press on an empty space to show the selection menu, with only the
       // paste button visible.
       await tester.longPressAt(textOffsetToPosition(tester, 4));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text(longLocalizations.cutButtonLabel), findsNothing);
       expect(find.text(longLocalizations.copyButtonLabel), findsNothing);
       expect(find.text(longLocalizations.pasteButtonLabel), findsOneWidget);

packages/flutter/test/material/date_picker_test.dart

@@ -3,12 +3,31 @@
 // found in the LICENSE file.
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../rendering/mock_canvas.dart';
 import 'feedback_tester.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;
+        break;
+    }
+  }
+}
+
 void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final MockClipboard mockClipboard = MockClipboard();
 
   DateTime firstDate;
   DateTime lastDate;
@@ -35,7 +54,7 @@ void main() {
     return tester.widget<TextField>(find.byType(TextField));
   }
 
-  setUp(() {
+  setUp(() async {
     firstDate = DateTime(2001, DateTime.january, 1);
     lastDate = DateTime(2031, DateTime.december, 31);
     initialDate = DateTime(2016, DateTime.january, 15);
@@ -51,6 +70,15 @@ void main() {
     fieldHintText = null;
     fieldLabelText = null;
     helpText = null;
+
+    // Fill the clipboard so that the PASTE option is available in the text
+    // selection menu.
+    SystemChannels.platform.setMockMethodCallHandler(mockClipboard.handleMethodCall);
+    await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
+  });
+
+  tearDown(() {
+    SystemChannels.platform.setMockMethodCallHandler(null);
   });
 
   Future<void> prepareDatePicker(WidgetTester tester, Future<void> callback(Future<DateTime> date)) async {
@@ -1018,7 +1046,6 @@ void main() {
 
       semantics.dispose();
     });
-
   });
 
   group('Screen configurations', () {

packages/flutter/test/material/search_test.dart

@@ -9,7 +9,37 @@ import 'package:flutter_test/flutter_test.dart';
 
 import '../widgets/semantics_tester.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;
+        break;
+    }
+  }
+}
+
 void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final MockClipboard mockClipboard = MockClipboard();
+
+  setUp(() async {
+    // Fill the clipboard so that the PASTE option is available in the text
+    // selection menu.
+    SystemChannels.platform.setMockMethodCallHandler(mockClipboard.handleMethodCall);
+    await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
+  });
+
+  tearDown(() {
+    SystemChannels.platform.setMockMethodCallHandler(null);
+  });
+
   testWidgets('Can open and close search', (WidgetTester tester) async {
     final _TestSearchDelegate delegate = _TestSearchDelegate();
     final List<String> selectedResults = <String>[];

packages/flutter/test/material/text_field_test.dart

@@ -142,8 +142,11 @@ void main() {
     kThreeLines +
     "\nFourth line won't display and ends at";
 
-  setUp(() {
+  setUp(() async {
     debugResetSemanticsIdCounter();
+    // Fill the clipboard so that the PASTE option is available in the text
+    // selection menu.
+    await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
   });
 
   final Key textFieldKey = UniqueKey();
@@ -1045,7 +1048,7 @@ void main() {
     const int dIndex = 3;
     final Offset dPos = textOffsetToPosition(tester, dIndex);
     await tester.longPressAt(dPos);
-    await tester.pump();
+    await tester.pumpAndSettle();
 
     // Context menu should not have paste and cut.
     expect(find.text('COPY'), findsOneWidget);
@@ -1783,6 +1786,8 @@ void main() {
       renderEditable,
     );
     await tester.tapAt(endpoints[0].point + const Offset(1.0, 1.0));
+    // Pump an extra frame to allow the selection menu to read the clipboard.
+    await tester.pump();
     await tester.pump();
 
     // Toolbar should fade in. Starting at 0% opacity.
@@ -1893,7 +1898,7 @@ void main() {
     // Long press to select text.
     final Offset bPos = textOffsetToPosition(tester, 1);
     await tester.longPressAt(bPos, pointer: 7);
-    await tester.pump();
+    await tester.pumpAndSettle();
 
     // Should only have paste option when whole obscure text is selected.
     expect(find.text('PASTE'), findsOneWidget);
@@ -1905,7 +1910,7 @@ void main() {
     final Offset iPos = textOffsetToPosition(tester, 10);
     final Offset slightRight = iPos + const Offset(30.0, 0.0);
     await tester.longPressAt(slightRight, pointer: 7);
-    await tester.pump();
+    await tester.pumpAndSettle();
 
     // Should have paste and select all options when collapse.
     expect(find.text('PASTE'), findsOneWidget);
@@ -5037,6 +5042,78 @@ void main() {
     semantics.dispose();
   });
 
+  testWidgets('When clipboard empty, no semantics paste option', (WidgetTester tester) async {
+    const String textInTextField = 'Hello';
+
+    final SemanticsTester semantics = SemanticsTester(tester);
+    final SemanticsOwner semanticsOwner = tester.binding.pipelineOwner.semanticsOwner;
+    final TextEditingController controller = TextEditingController()
+      ..text = textInTextField;
+    final Key key = UniqueKey();
+
+    // Clear the clipboard.
+    await Clipboard.setData(const ClipboardData(text: ''));
+
+    await tester.pumpWidget(
+      overlay(
+        child: TextField(
+          key: key,
+          controller: controller,
+        ),
+      ),
+    );
+
+    const int inputFieldId = 1;
+
+    expect(semantics, hasSemantics(
+      TestSemantics.root(
+        children: <TestSemantics>[
+          TestSemantics(
+            id: inputFieldId,
+            flags: <SemanticsFlag>[SemanticsFlag.isTextField],
+            actions: <SemanticsAction>[SemanticsAction.tap],
+            value: textInTextField,
+            textDirection: TextDirection.ltr,
+          ),
+        ],
+      ),
+      ignoreRect: true, ignoreTransform: true,
+    ));
+
+    semanticsOwner.performAction(inputFieldId, SemanticsAction.tap);
+    await tester.pump();
+
+    expect(semantics, hasSemantics(
+      TestSemantics.root(
+        children: <TestSemantics>[
+          TestSemantics(
+            id: inputFieldId,
+            flags: <SemanticsFlag>[
+              SemanticsFlag.isTextField,
+              SemanticsFlag.isFocused,
+            ],
+            actions: <SemanticsAction>[
+              SemanticsAction.tap,
+              SemanticsAction.moveCursorBackwardByCharacter,
+              SemanticsAction.moveCursorBackwardByWord,
+              SemanticsAction.setSelection,
+              // No paste option.
+            ],
+            value: textInTextField,
+            textDirection: TextDirection.ltr,
+            textSelection: const TextSelection(
+              baseOffset: textInTextField.length,
+              extentOffset: textInTextField.length,
+            ),
+          ),
+        ],
+      ),
+      ignoreRect: true, ignoreTransform: true,
+    ));
+
+    semantics.dispose();
+  });
+
   testWidgets('TextField throws when not descended from a Material widget', (WidgetTester tester) async {
     const Widget textField = TextField();
     await tester.pumpWidget(textField);
@@ -5798,7 +5875,7 @@ void main() {
         const TextSelection.collapsed(offset: 8, affinity: TextAffinity.downstream),
       );
       await tester.tapAt(textfieldStart + const Offset(150.0, 9.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Second tap selects the word around the cursor.
       expect(
@@ -5843,7 +5920,7 @@ void main() {
         const TextSelection.collapsed(offset: 9),
       );
       await tester.tapAt(textfieldStart + const Offset(150.0, 9.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Second tap selects the word around the cursor.
       expect(
@@ -5894,7 +5971,7 @@ void main() {
 
       // Second tap selects the word around the cursor.
       await tester.tapAt(textOffsetToPosition(tester, index));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(
         controller.selection,
         const TextSelection(baseOffset: 0, extentOffset: 7),
@@ -5926,14 +6003,14 @@ void main() {
       await tester.tapAt(textOffsetToPosition(tester, 0));
       await tester.pump(const Duration(milliseconds: 50));
       await tester.tapAt(textOffsetToPosition(tester, 0));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('PASTE'), findsOneWidget);
 
       // Double tap again keeps the selection menu visible.
       await tester.tapAt(textOffsetToPosition(tester, 0));
       await tester.pump(const Duration(milliseconds: 50));
       await tester.tapAt(textOffsetToPosition(tester, 0));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('PASTE'), findsOneWidget);
     },
   );
@@ -5958,7 +6035,7 @@ void main() {
 
       // Long press shows the selection menu.
       await tester.longPressAt(textOffsetToPosition(tester, 0));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('PASTE'), findsOneWidget);
 
       // Long press again keeps the selection menu visible.
@@ -5988,7 +6065,7 @@ void main() {
 
       // Long press shows the selection menu.
       await tester.longPress(find.byType(TextField));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('PASTE'), findsOneWidget);
 
       // Tap hides the selection menu.
@@ -6023,7 +6100,7 @@ void main() {
       // Long press shows the selection menu.
       expect(find.text('PASTE'), findsNothing);
       await tester.longPress(find.byType(TextField));
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('PASTE'), findsOneWidget);
     },
   );
@@ -6053,7 +6130,7 @@ void main() {
       final TestGesture gesture =
          await tester.startGesture(textfieldStart + const Offset(150.0, 9.0));
       // Hold the press.
-      await tester.pump(const Duration(milliseconds: 500));
+      await tester.pumpAndSettle();
 
       expect(
         controller.selection,
@@ -6142,7 +6219,7 @@ void main() {
       final Offset textfieldStart = tester.getTopLeft(find.byType(TextField));
 
       await tester.longPressAt(textfieldStart + const Offset(50.0, 9.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Collapsed cursor for iOS long press.
       expect(
@@ -6175,7 +6252,7 @@ void main() {
       final Offset textfieldStart = tester.getTopLeft(find.byType(TextField));
 
       await tester.longPressAt(textfieldStart + const Offset(50.0, 9.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       expect(
         controller.selection,
@@ -6278,7 +6355,7 @@ void main() {
       expect(find.byType(CupertinoButton), findsNothing);
 
       await gesture.up();
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // The selection isn't affected by the gesture lift.
       expect(
@@ -6352,7 +6429,7 @@ void main() {
     expect(find.byType(CupertinoButton), findsNothing);
 
     await gesture.up();
-    await tester.pump();
+    await tester.pumpAndSettle();
 
     // The selection isn't affected by the gesture lift.
     expect(
@@ -6409,7 +6486,7 @@ void main() {
       await tester.pump(const Duration(milliseconds: 500));
 
       await tester.longPressAt(textfieldStart + const Offset(100.0, 9.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Plain collapsed selection at the exact tap position.
       expect(
@@ -6452,7 +6529,7 @@ void main() {
         const TextSelection.collapsed(offset: 8, affinity: TextAffinity.downstream),
       );
       await tester.tapAt(textfieldStart + const Offset(150.0, 9.0));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // Double tap selection.
       expect(
@@ -6487,7 +6564,7 @@ void main() {
         const TextSelection.collapsed(offset: 7, affinity: TextAffinity.upstream),
       );
       await tester.tapAt(textfieldStart + const Offset(50.0, 9.0));
-      await tester.pump(const Duration(milliseconds: 50));
+      await tester.pumpAndSettle();
       expect(
         controller.selection,
         const TextSelection(baseOffset: 0, extentOffset: 7),
@@ -6503,7 +6580,7 @@ void main() {
         const TextSelection.collapsed(offset: 7, affinity: TextAffinity.upstream),
       );
       await tester.tapAt(textfieldStart + const Offset(100.0, 9.0));
-      await tester.pump(const Duration(milliseconds: 50));
+      await tester.pumpAndSettle();
       expect(
         controller.selection,
         const TextSelection(baseOffset: 0, extentOffset: 7),
@@ -6518,7 +6595,7 @@ void main() {
         const TextSelection.collapsed(offset: 8, affinity: TextAffinity.downstream),
       );
       await tester.tapAt(textfieldStart + const Offset(150.0, 9.0));
-      await tester.pump(const Duration(milliseconds: 50));
+      await tester.pumpAndSettle();
       expect(
         controller.selection,
         const TextSelection(baseOffset: 8, extentOffset: 12),
@@ -6610,7 +6687,7 @@ void main() {
     );
 
     await gesture.up();
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.byType(CupertinoButton), findsNWidgets(3));
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));
 

packages/flutter/test/material/text_selection_test.dart

@@ -5,10 +5,35 @@
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import '../widgets/text.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;
+        break;
+    }
+  }
+}
+
 void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final MockClipboard mockClipboard = MockClipboard();
+  SystemChannels.platform.setMockMethodCallHandler(mockClipboard.handleMethodCall);
+
+  setUp(() async {
+    await Clipboard.setData(const ClipboardData(text: 'clipboard data'));
+  });
+
   group('canSelectAll', () {
     Widget createEditableText({
       Key key,
@@ -104,7 +129,7 @@ void main() {
       expect(endpoints.length, 1);
       final Offset handlePos = endpoints[0].point + const Offset(0.0, 1.0);
       await tester.tapAt(handlePos, pointer: 7);
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('CUT'), findsNothing);
       expect(find.text('COPY'), findsNothing);
       expect(find.text('PASTE'), findsOneWidget);
@@ -235,7 +260,7 @@ void main() {
       // Long press to show the menu.
       final Offset textOffset = textOffsetToPosition(tester, 1);
       await tester.longPressAt(textOffset);
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // The last two buttons are missing, and a more button is shown.
       expect(find.text('CUT'), findsOneWidget);
@@ -301,7 +326,7 @@ void main() {
       // Long press to show the menu.
       final Offset textOffset = textOffsetToPosition(tester, 1);
       await tester.longPressAt(textOffset);
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // The last button is missing, and a more button is shown.
       expect(find.text('CUT'), findsOneWidget);
@@ -413,7 +438,7 @@ void main() {
 
       // Long press to show the menu.
       await tester.longPressAt(textOffsetToPosition(tester, 1));
-      await tester.pump();
+      await tester.pumpAndSettle();
 
       // The last button is missing, and a more button is shown.
       expect(find.text('CUT'), findsOneWidget);
@@ -488,7 +513,7 @@ void main() {
       expect(endpoints.length, 1);
       final Offset handlePos = endpoints[0].point + const Offset(0.0, 1.0);
       await tester.tapAt(handlePos, pointer: 7);
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('CUT'), findsNothing);
       expect(find.text('COPY'), findsNothing);
       expect(find.text('PASTE'), findsOneWidget);
@@ -556,4 +581,58 @@ void main() {
       );
     });
   });
+
+  testWidgets('Paste only appears when clipboard has contents', (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 to start.
+    await Clipboard.setData(const ClipboardData(text: ''));
+
+    // Double tap to selet 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();
+
+    // No Paste yet, because nothing has been copied.
+    expect(find.text('PASTE'), findsNothing);
+    expect(find.text('COPY'), findsOneWidget);
+    expect(find.text('CUT'), findsOneWidget);
+    expect(find.text('SELECT ALL'), 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);
+    expect(find.text('SELECT ALL'), 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 now shows.
+    expect(find.text('COPY'), findsOneWidget);
+    expect(find.text('CUT'), findsOneWidget);
+    expect(find.text('PASTE'), findsOneWidget);
+    expect(find.text('SELECT ALL'), findsOneWidget);
+  }, skip: isBrowser);
 }

packages/flutter/test/widgets/editable_text_cursor_test.dart

@@ -19,6 +19,12 @@ const TextStyle textStyle = TextStyle();
 const Color cursorColor = Color.fromARGB(0xFF, 0xFF, 0x00, 0x00);
 
 void main() {
+  setUp(() async {
+    // Fill the clipboard so that the PASTE option is available in the text
+    // selection menu.
+    await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
+  });
+
   testWidgets('cursor has expected width and radius', (WidgetTester tester) async {
     await tester.pumpWidget(
         MediaQuery(data: const MediaQueryData(devicePixelRatio: 1.0),
@@ -39,7 +45,6 @@ void main() {
     expect(editableText.cursorRadius.x, 2.0);
   });
 
-
   testWidgets('cursor layout has correct width', (WidgetTester tester) async {
     final GlobalKey<EditableTextState> editableTextKey = GlobalKey<EditableTextState>();
 
@@ -132,7 +137,7 @@ void main() {
     final Finder textFinder = find.byKey(editableTextKey);
     await tester.longPress(textFinder);
     tester.state<EditableTextState>(textFinder).showToolbar();
-    await tester.pump();
+    await tester.pumpAndSettle();
 
     await tester.tap(find.text('PASTE'));
     await tester.pump();

packages/flutter/test/widgets/editable_text_test.dart

@@ -48,9 +48,12 @@ void main() {
   final MockClipboard mockClipboard = MockClipboard();
   SystemChannels.platform.setMockMethodCallHandler(mockClipboard.handleMethodCall);
 
-  setUp(() {
+  setUp(() async {
     debugResetSemanticsIdCounter();
     controller = TextEditingController();
+    // Fill the clipboard so that the PASTE option is available in the text
+    // selection menu.
+    await Clipboard.setData(const ClipboardData(text: 'Clipboard data'));
   });
 
   tearDown(() {
@@ -961,7 +964,7 @@ void main() {
 
     // Can't show the toolbar when there's no focus.
     expect(state.showToolbar(), false);
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.text('PASTE'), findsNothing);
 
     // Can show the toolbar when focused even though there's no text.
@@ -971,7 +974,7 @@ void main() {
     );
     await tester.pump();
     expect(state.showToolbar(), true);
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.text('PASTE'), findsOneWidget);
 
     // Hide the menu again.
@@ -983,7 +986,7 @@ void main() {
     controller.text = 'blah';
     await tester.pump();
     expect(state.showToolbar(), true);
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.text('PASTE'), findsOneWidget);
   }, skip: isBrowser);
 
@@ -1023,7 +1026,7 @@ void main() {
 
     // Should be able to show the toolbar.
     expect(state.showToolbar(), true);
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.text('PASTE'), findsOneWidget);
   });
 
@@ -1192,7 +1195,7 @@ void main() {
     final Finder textFinder = find.byType(EditableText);
     await tester.longPress(textFinder);
     tester.state<EditableTextState>(textFinder).showToolbar();
-    await tester.pump();
+    await tester.pumpAndSettle();
 
     await tester.tap(find.text('PASTE'));
     await tester.pump();
@@ -2412,12 +2415,13 @@ void main() {
 
       controls = MockTextSelectionControls();
       when(controls.buildHandle(any, any, any)).thenReturn(Container());
-      when(controls.buildToolbar(any, any, any, any, any, any))
+      when(controls.buildToolbar(any, any, any, any, any, any, any))
           .thenReturn(Container());
     });
 
     testWidgets('are exposed', (WidgetTester tester) async {
       final SemanticsTester semantics = SemanticsTester(tester);
+      addTearDown(semantics.dispose);
 
       when(controls.canCopy(any)).thenReturn(false);
       when(controls.canCut(any)).thenReturn(false);
@@ -2457,6 +2461,7 @@ void main() {
       when(controls.canCopy(any)).thenReturn(false);
       when(controls.canPaste(any)).thenReturn(true);
       await _buildApp(controls, tester);
+      await tester.pumpAndSettle();
       expect(
         semantics,
         includesNodeWith(
@@ -2504,8 +2509,6 @@ void main() {
           ],
         ),
       );
-
-      semantics.dispose();
     });
 
     testWidgets('can copy/cut/paste with a11y', (WidgetTester tester) async {
@@ -2564,7 +2567,7 @@ void main() {
       );
 
       owner.performAction(expectedNodeId, SemanticsAction.copy);
-      verify(controls.handleCopy(any)).called(1);
+      verify(controls.handleCopy(any, any)).called(1);
 
       owner.performAction(expectedNodeId, SemanticsAction.cut);
       verify(controls.handleCut(any)).called(1);