Reland "Single tap on the previous selection should toggle the toolbar on iOS #108913" (#111995)

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

@@ -102,7 +102,6 @@ class _CupertinoTextFieldSelectionGestureDetectorBuilder extends TextSelectionGe
 
   @override
   void onSingleTapUp(TapUpDetails details) {
-    editableText.hideToolbar();
     // Because TextSelectionGestureDetector listens to taps that happen on
     // widgets in front of it, tapping the clear button will also trigger
     // this handler. If the clear button widget recognizes the up event,

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

@@ -103,7 +103,6 @@ class _TextFieldSelectionGestureDetectorBuilder extends TextSelectionGestureDete
 
   @override
   void onSingleTapUp(TapUpDetails details) {
-    editableText.hideToolbar();
     super.onSingleTapUp(details);
     _state._requestKeyboard();
     _state.widget.onTap?.call();

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

@@ -2724,8 +2724,8 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     _scribbleCacheKey = null;
   }
 
-  void _createSelectionOverlay() {
-    _selectionOverlay = TextSelectionOverlay(
+  TextSelectionOverlay _createSelectionOverlay() {
+    final TextSelectionOverlay selectionOverlay = TextSelectionOverlay(
       clipboardStatus: _clipboardStatus,
       context: context,
       value: _value,
@@ -2740,6 +2740,8 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
       onSelectionHandleTapped: widget.onSelectionHandleTapped,
       magnifierConfiguration: widget.magnifierConfiguration,
     );
+
+    return selectionOverlay;
   }
 
   @pragma('vm:notify-debugger-on-exception')
@@ -2780,7 +2782,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
       _selectionOverlay = null;
     } else {
       if (_selectionOverlay == null) {
-        _createSelectionOverlay();
+        _selectionOverlay = _createSelectionOverlay();
       } else {
         _selectionOverlay!.update(_value);
       }
@@ -3266,7 +3268,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     if (value == textEditingValue) {
       if (!widget.focusNode.hasFocus) {
         widget.focusNode.requestFocus();
-        _createSelectionOverlay();
+        _selectionOverlay = _createSelectionOverlay();
       }
       return;
     }
@@ -3317,10 +3319,11 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   /// Toggles the visibility of the toolbar.
-  void toggleToolbar() {
-    assert(_selectionOverlay != null);
-    if (_selectionOverlay!.toolbarIsVisible) {
-      hideToolbar();
+  void toggleToolbar([bool hideHandles = true]) {
+    final TextSelectionOverlay selectionOverlay = _selectionOverlay ??= _createSelectionOverlay();
+
+    if (selectionOverlay.toolbarIsVisible) {
+      hideToolbar(hideHandles);
     } else {
       showToolbar();
     }

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

@@ -1635,6 +1635,26 @@ class TextSelectionGestureDetectorBuilder {
         && renderEditable.selection!.end >= textPosition.offset;
   }
 
+  bool _positionWasOnSelectionExclusive(TextPosition textPosition) {
+    final TextSelection? selection = renderEditable.selection;
+    if (selection == null) {
+      return false;
+    }
+
+    return selection.start < textPosition.offset
+        && selection.end > textPosition.offset;
+  }
+
+  bool _positionWasOnSelectionInclusive(TextPosition textPosition) {
+    final TextSelection? selection = renderEditable.selection;
+    if (selection == null) {
+      return false;
+    }
+
+    return selection.start <= textPosition.offset
+        && selection.end >= textPosition.offset;
+  }
+
   // Expand the selection to the given global position.
   //
   // Either base or extent will be moved to the last tapped position, whichever
@@ -1879,6 +1899,7 @@ class TextSelectionGestureDetectorBuilder {
         case TargetPlatform.linux:
         case TargetPlatform.macOS:
         case TargetPlatform.windows:
+          editableText.hideToolbar();
           // On desktop platforms the selection is set on tap down.
           if (_isShiftTapping) {
             _isShiftTapping = false;
@@ -1886,6 +1907,7 @@ class TextSelectionGestureDetectorBuilder {
           break;
         case TargetPlatform.android:
         case TargetPlatform.fuchsia:
+          editableText.hideToolbar();
           if (isShiftPressedValid) {
             _isShiftTapping = true;
             _extendSelection(details.globalPosition, SelectionChangedCause.tap);
@@ -1918,8 +1940,32 @@ class TextSelectionGestureDetectorBuilder {
               break;
             case PointerDeviceKind.touch:
             case PointerDeviceKind.unknown:
-              // On iOS/iPadOS a touch tap places the cursor at the edge of the word.
+              // Toggle the toolbar if the `previousSelection` is collapsed, the tap is on the selection, the
+              // TextAffinity remains the same, and the editable is focused. The TextAffinity is important when the
+              // cursor is on the boundary of a line wrap, if the affinity is different (i.e. it is downstream), the
+              // selection should move to the following line and not toggle the toolbar.
+              //
+              // Toggle the toolbar when the tap is exclusively within the bounds of a non-collapsed `previousSelection`,
+              // and the editable is focused.
+              //
+              // Selects the word edge closest to the tap when the editable is not focused, or if the tap was neither exclusively
+              // or inclusively on `previousSelection`. If the selection remains the same after selecting the word edge, then we
+              // toggle the toolbar. If the selection changes then we hide the toolbar.
+              final TextSelection previousSelection = renderEditable.selection ?? editableText.textEditingValue.selection;
+              final TextPosition textPosition = renderEditable.getPositionForPoint(details.globalPosition);
+              final bool isAffinityTheSame = textPosition.affinity == previousSelection.affinity;
+              if (((_positionWasOnSelectionExclusive(textPosition) && !previousSelection.isCollapsed)
+                  || (_positionWasOnSelectionInclusive(textPosition) && previousSelection.isCollapsed && isAffinityTheSame))
+                  && renderEditable.hasFocus) {
+                editableText.toggleToolbar(false);
+              } else {
                 renderEditable.selectWordEdge(cause: SelectionChangedCause.tap);
+                if (previousSelection == editableText.textEditingValue.selection && renderEditable.hasFocus) {
+                  editableText.toggleToolbar(false);
+                } else {
+                  editableText.hideToolbar(false);
+                }
+              }
               break;
           }
           break;

packages/flutter/test/widgets/text_selection_test.dart

@@ -570,6 +570,38 @@ void main() {
     }
   }, variant: TargetPlatformVariant.all());
 
+  testWidgets('test TextSelectionGestureDetectorBuilder toggles toolbar on single tap on previous selection iOS', (WidgetTester tester) async {
+    await pumpTextSelectionGestureDetectorBuilder(tester);
+
+    final FakeEditableTextState state = tester.state(find.byType(FakeEditableText));
+    final FakeRenderEditable renderEditable = tester.renderObject(find.byType(FakeEditable));
+    expect(state.showToolbarCalled, isFalse);
+    expect(state.toggleToolbarCalled, isFalse);
+    renderEditable.selection = const TextSelection(baseOffset: 2, extentOffset: 6);
+    renderEditable.hasFocus = true;
+
+    final TestGesture gesture = await tester.startGesture(
+      const Offset(25.0, 200.0),
+      pointer: 0,
+    );
+    await gesture.up();
+    await tester.pumpAndSettle();
+
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.iOS:
+        expect(renderEditable.selectWordEdgeCalled, isFalse);
+        expect(state.toggleToolbarCalled, isTrue);
+        break;
+      case TargetPlatform.macOS:
+      case TargetPlatform.android:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+        expect(renderEditable.selectPositionAtCalled, isTrue);
+        break;
+    }
+  }, variant: TargetPlatformVariant.all());
+
   testWidgets('test TextSelectionGestureDetectorBuilder double tap', (WidgetTester tester) async {
     await pumpTextSelectionGestureDetectorBuilder(tester);
     final TestGesture gesture = await tester.startGesture(
@@ -1519,6 +1551,7 @@ class FakeEditableText extends EditableText {
 class FakeEditableTextState extends EditableTextState {
   final GlobalKey _editableKey = GlobalKey();
   bool showToolbarCalled = false;
+  bool toggleToolbarCalled = false;
 
   @override
   RenderEditable get renderEditable => _editableKey.currentContext!.findRenderObject()! as RenderEditable;
@@ -1530,7 +1563,8 @@ class FakeEditableTextState extends EditableTextState {
   }
 
   @override
-  void toggleToolbar() {
+  void toggleToolbar([bool hideHandles = true]) {
+    toggleToolbarCalled = true;
     return;
   }