Keep the selection after 'Copy' pressed on iOS. (#76327)

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

@@ -6,6 +6,7 @@ import 'dart:math' as math;
 
 import 'package:flutter/widgets.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter/services.dart';
 
 import 'localizations.dart';
 import 'text_selection_toolbar.dart';

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

@@ -774,7 +774,11 @@ abstract class TextSelectionDelegate {
   set textEditingValue(TextEditingValue value);
 
   /// Hides the text selection toolbar.
-  void hideToolbar();
+  ///
+  /// By default, hideHandles is true, and the toolbar is hidden along with its
+  /// handles. If hideHandles is set to false, then the toolbar will be hidden
+  /// but the handles will remain.
+  void hideToolbar([bool hideHandles = true]);
 
   /// Brings the provided [TextPosition] into the visible area of the text
   /// input.

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

@@ -2505,8 +2505,14 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   @override
-  void hideToolbar() {
-    _selectionOverlay?.hide();
+  void hideToolbar([bool hideHandles = true]) {
+    if (hideHandles) {
+      // Hide the handles and the toolbar.
+      _selectionOverlay?.hide();
+    } else {
+      // Hide only the toolbar but not the handles.
+      _selectionOverlay?.hideToolbar();
+    }
   }
 
   /// Toggles the visibility of the toolbar.

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

@@ -228,12 +228,26 @@ abstract class TextSelectionControls {
       text: value.selection.textInside(value.text),
     ));
     clipboardStatus?.update();
-    delegate.textEditingValue = TextEditingValue(
-      text: value.text,
-      selection: TextSelection.collapsed(offset: value.selection.end),
-    );
     delegate.bringIntoView(delegate.textEditingValue.selection.extent);
-    delegate.hideToolbar();
+
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.iOS:
+        // Hide the toolbar, but keep the selection and keep the handles.
+        delegate.hideToolbar(false);
+        return;
+      case TargetPlatform.macOS:
+      case TargetPlatform.android:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+        // Collapse the selection and hide the toolbar and handles.
+        delegate.textEditingValue = TextEditingValue(
+          text: value.text,
+          selection: TextSelection.collapsed(offset: value.selection.end),
+        );
+        delegate.hideToolbar();
+        return;
+    }
   }
 
   /// Paste the current clipboard selection (obtained from [Clipboard]) into

packages/flutter/test/cupertino/text_selection_test.dart

@@ -197,17 +197,34 @@ void main() {
     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));

packages/flutter/test/rendering/editable_test.dart

@@ -19,7 +19,7 @@ class FakeEditableTextState with TextSelectionDelegate {
   TextEditingValue textEditingValue = TextEditingValue.empty;
 
   @override
-  void hideToolbar() { }
+  void hideToolbar([bool hideHandles = true]) { }
 
   @override
   void bringIntoView(TextPosition position) { }