SelectableRegion onSelectionChange should be called when the selection changes (#134215)

This change makes sure to call `onSelectionChange` in all cases when selection might change including:
* Dragging selection handles
* Mouse drag to select
* Keyboard actions
* Long press drag to select

Author: Renzo-Olivares

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

@@ -502,13 +502,15 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
       case 2:
         _selectWordAt(offset: details.globalPosition);
     }
+    _updateSelectedContentIfNeeded();
   }
 
   void _handleMouseDragStart(TapDragStartDetails details) {
     switch (_getEffectiveConsecutiveTapCount(details.consecutiveTapCount)) {
       case 1:
         _selectStartTo(offset: details.globalPosition);
     }
+    _updateSelectedContentIfNeeded();
   }
 
   void _handleMouseDragUpdate(TapDragUpdateDetails details) {
@@ -518,6 +520,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
       case 2:
         _selectEndTo(offset: details.globalPosition, continuous: true, textGranularity: TextGranularity.word);
     }
+    _updateSelectedContentIfNeeded();
   }
 
   void _handleMouseDragEnd(TapDragEndDetails details) {
@@ -543,6 +546,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
 
   void _handleTouchLongPressMoveUpdate(LongPressMoveUpdateDetails details) {
     _selectEndTo(offset: details.globalPosition, textGranularity: TextGranularity.word);
+    _updateSelectedContentIfNeeded();
   }
 
   void _handleTouchLongPressEnd(LongPressEndDetails details) {
@@ -717,6 +721,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
       details.globalPosition,
       _selectionDelegate.value.startSelectionPoint!,
     ));
+    _updateSelectedContentIfNeeded();
   }
 
   void _handleSelectionStartHandleDragUpdate(DragUpdateDetails details) {
@@ -730,6 +735,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
       details.globalPosition,
       _selectionDelegate.value.startSelectionPoint!,
     ));
+    _updateSelectedContentIfNeeded();
   }
 
   void _handleSelectionEndHandleDragStart(DragStartDetails details) {
@@ -742,6 +748,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
       details.globalPosition,
       _selectionDelegate.value.endSelectionPoint!,
     ));
+    _updateSelectedContentIfNeeded();
   }
 
   void _handleSelectionEndHandleDragUpdate(DragUpdateDetails details) {
@@ -755,6 +762,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
       details.globalPosition,
       _selectionDelegate.value.endSelectionPoint!,
     ));
+    _updateSelectedContentIfNeeded();
   }
 
   MagnifierInfo _buildInfoForMagnifier(Offset globalGesturePosition, SelectionPoint selectionPoint) {
@@ -1067,6 +1075,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
         granularity: granularity,
       ),
     );
+    _updateSelectedContentIfNeeded();
   }
 
   double? _directionalHorizontalBaseline;
@@ -1088,6 +1097,7 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
         dx: globalSelectionPointOffset.dx,
       ),
     );
+    _updateSelectedContentIfNeeded();
   }
 
   // [TextSelectionDelegate] overrides.

packages/flutter/test/widgets/selectable_region_test.dart

@@ -2713,7 +2713,7 @@ void main() {
     skip: kIsWeb, // [intended]
   );
 
-  testWidgets('onSelectionChange is called when the selection changes', (WidgetTester tester) async {
+  testWidgets('onSelectionChange is called when the selection changes through gestures', (WidgetTester tester) async {
     SelectedContent? content;
 
     await tester.pumpWidget(
@@ -2728,27 +2728,264 @@ void main() {
         ),
       ),
     );
+
     final RenderParagraph paragraph = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('How are you'), matching: find.byType(RichText)));
-    final TestGesture gesture = await tester.startGesture(textOffsetToPosition(paragraph, 4), kind: PointerDeviceKind.mouse);
+    final TestGesture mouseGesture = await tester.startGesture(textOffsetToPosition(paragraph, 4), kind: PointerDeviceKind.mouse);
+    final TestGesture touchGesture = await tester.createGesture();
+
     expect(content, isNull);
-    addTearDown(gesture.removePointer);
+    addTearDown(mouseGesture.removePointer);
+    addTearDown(touchGesture.removePointer);
     await tester.pump();
 
-    await gesture.moveTo(textOffsetToPosition(paragraph, 7));
-    await gesture.up();
-    await tester.pump();
+    // Called on drag.
+    await mouseGesture.moveTo(textOffsetToPosition(paragraph, 7));
+    await tester.pumpAndSettle();
     expect(content, isNotNull);
     expect(content!.plainText, 'are');
 
+    // Updates on drag.
+    await mouseGesture.moveTo(textOffsetToPosition(paragraph, 10));
+    await tester.pumpAndSettle();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'are yo');
+
+    // Called on drag end.
+    await mouseGesture.up();
+    await tester.pump();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'are yo');
+
     // Backwards selection.
-    await gesture.down(textOffsetToPosition(paragraph, 3));
+    await mouseGesture.down(textOffsetToPosition(paragraph, 3));
     await tester.pumpAndSettle();
     expect(content, isNull);
-    await gesture.moveTo(textOffsetToPosition(paragraph, 0));
-    await gesture.up();
+
+    await mouseGesture.moveTo(textOffsetToPosition(paragraph, 0));
+    await tester.pumpAndSettle();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'How');
+
+    await mouseGesture.up();
+    await tester.pump();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'How');
+
+    // Called on double tap.
+    await mouseGesture.down(textOffsetToPosition(paragraph, 6));
+    await tester.pump();
+    await mouseGesture.up();
     await tester.pump();
+    await mouseGesture.down(textOffsetToPosition(paragraph, 6));
+    await tester.pumpAndSettle();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'are');
+    await mouseGesture.up();
+    await tester.pumpAndSettle();
+
+    // Called on tap.
+    await mouseGesture.down(textOffsetToPosition(paragraph, 0));
+    await tester.pumpAndSettle();
+    expect(content, isNull);
+    await mouseGesture.up();
+    await tester.pumpAndSettle();
+
+    // With touch gestures.
+
+    // Called on long press start.
+    await touchGesture.down(textOffsetToPosition(paragraph, 0));
+    await tester.pumpAndSettle(kLongPressTimeout);
     expect(content, isNotNull);
     expect(content!.plainText, 'How');
+
+    // Called on long press update.
+    await touchGesture.moveTo(textOffsetToPosition(paragraph, 5));
+    await tester.pumpAndSettle();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'How are');
+
+    // Called on long press end.
+    await touchGesture.up();
+    await tester.pumpAndSettle();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'How are');
+
+    // Long press to select 'you'.
+    await touchGesture.down(textOffsetToPosition(paragraph, 9));
+    await tester.pumpAndSettle(kLongPressTimeout);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'you');
+    await touchGesture.up();
+    await tester.pumpAndSettle();
+
+    // Called while moving selection handles.
+    final List<TextBox> boxes = paragraph.getBoxesForSelection(paragraph.selections[0]);
+    expect(boxes.length, 1);
+    final Offset startHandlePos = globalize(boxes[0].toRect().bottomLeft, paragraph);
+    final Offset endHandlePos = globalize(boxes[0].toRect().bottomRight, paragraph);
+    final Offset startPos = Offset(textOffsetToPosition(paragraph, 4).dx, startHandlePos.dy);
+    final Offset endPos = Offset(textOffsetToPosition(paragraph, 6).dx, endHandlePos.dy);
+
+    // Start handle.
+    await touchGesture.down(startHandlePos);
+    await touchGesture.moveTo(startPos);
+    await tester.pumpAndSettle();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'are you');
+    await touchGesture.up();
+    await tester.pumpAndSettle();
+
+    // End handle.
+    await touchGesture.down(endHandlePos);
+    await touchGesture.moveTo(endPos);
+    await tester.pumpAndSettle();
+    expect(content, isNotNull);
+    expect(content!.plainText, 'ar');
+    await touchGesture.up();
+    await tester.pumpAndSettle();
+  });
+
+  testWidgets('onSelectionChange is called when the selection changes through keyboard actions', (WidgetTester tester) async {
+    SelectedContent? content;
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: SelectableRegion(
+          onSelectionChanged: (SelectedContent? selectedContent) => content = selectedContent,
+          focusNode: FocusNode(),
+          selectionControls: materialTextSelectionControls,
+          child: const Column(
+            children: <Widget>[
+              Text('How are you?'),
+              Text('Good, and you?'),
+              Text('Fine, thank you.'),
+            ],
+          ),
+        ),
+      ),
+    );
+
+    expect(content, isNull);
+    await tester.pump();
+
+    final RenderParagraph paragraph1 = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('How are you?'), matching: find.byType(RichText)));
+    final RenderParagraph paragraph2 = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('Good, and you?'), matching: find.byType(RichText)));
+    final RenderParagraph paragraph3 = tester.renderObject<RenderParagraph>(find.descendant(of: find.text('Fine, thank you.'), matching: find.byType(RichText)));
+    final TestGesture gesture = await tester.startGesture(textOffsetToPosition(paragraph1, 2), kind: PointerDeviceKind.mouse);
+    addTearDown(gesture.removePointer);
+    await tester.pump();
+    await gesture.moveTo(textOffsetToPosition(paragraph1, 6));
+    await gesture.up();
+    await tester.pump();
+
+    expect(paragraph1.selections.length, 1);
+    expect(paragraph1.selections[0].start, 2);
+    expect(paragraph1.selections[0].end, 6);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w ar');
+
+    await sendKeyCombination(tester, const SingleActivator(LogicalKeyboardKey.arrowRight, shift: true));
+    await tester.pump();
+    expect(paragraph1.selections.length, 1);
+    expect(paragraph1.selections[0].start, 2);
+    expect(paragraph1.selections[0].end, 7);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w are');
+
+    for (int i = 0; i < 5; i += 1) {
+      await sendKeyCombination(tester,
+          const SingleActivator(LogicalKeyboardKey.arrowRight, shift: true));
+      await tester.pump();
+      expect(paragraph1.selections.length, 1);
+      expect(paragraph1.selections[0].start, 2);
+      expect(paragraph1.selections[0].end, 8 + i);
+      expect(content, isNotNull);
+    }
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w are you?');
+
+    for (int i = 0; i < 5; i += 1) {
+      await sendKeyCombination(tester,
+          const SingleActivator(LogicalKeyboardKey.arrowLeft, shift: true));
+      await tester.pump();
+      expect(paragraph1.selections.length, 1);
+      expect(paragraph1.selections[0].start, 2);
+      expect(paragraph1.selections[0].end, 11 - i);
+      expect(content, isNotNull);
+    }
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w are');
+
+    await sendKeyCombination(tester, const SingleActivator(LogicalKeyboardKey.arrowDown, shift: true));
+    await tester.pump();
+    expect(paragraph1.selections.length, 1);
+    expect(paragraph1.selections[0].start, 2);
+    expect(paragraph1.selections[0].end, 12);
+    expect(paragraph2.selections.length, 1);
+    expect(paragraph2.selections[0].start, 0);
+    expect(paragraph2.selections[0].end, 8);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w are you?Good, an');
+
+    await sendKeyCombination(tester, const SingleActivator(LogicalKeyboardKey.arrowDown, shift: true));
+    await tester.pump();
+    expect(paragraph1.selections.length, 1);
+    expect(paragraph1.selections[0].start, 2);
+    expect(paragraph1.selections[0].end, 12);
+    expect(paragraph2.selections.length, 1);
+    expect(paragraph2.selections[0].start, 0);
+    expect(paragraph2.selections[0].end, 14);
+    expect(paragraph3.selections.length, 1);
+    expect(paragraph3.selections[0].start, 0);
+    expect(paragraph3.selections[0].end, 9);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w are you?Good, and you?Fine, tha');
+
+    await sendKeyCombination(tester, const SingleActivator(LogicalKeyboardKey.arrowDown, shift: true));
+    await tester.pump();
+    expect(paragraph1.selections.length, 1);
+    expect(paragraph1.selections[0].start, 2);
+    expect(paragraph1.selections[0].end, 12);
+    expect(paragraph2.selections.length, 1);
+    expect(paragraph2.selections[0].start, 0);
+    expect(paragraph2.selections[0].end, 14);
+    expect(paragraph3.selections.length, 1);
+    expect(paragraph3.selections[0].start, 0);
+    expect(paragraph3.selections[0].end, 16);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w are you?Good, and you?Fine, thank you.');
+
+    await sendKeyCombination(tester, const SingleActivator(LogicalKeyboardKey.arrowUp, shift: true));
+    await tester.pump();
+    expect(paragraph1.selections.length, 1);
+    expect(paragraph1.selections[0].start, 2);
+    expect(paragraph1.selections[0].end, 12);
+    expect(paragraph2.selections.length, 1);
+    expect(paragraph2.selections[0].start, 0);
+    expect(paragraph2.selections[0].end, 8);
+    expect(paragraph3.selections.length, 0);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w are you?Good, an');
+
+    await sendKeyCombination(tester, const SingleActivator(LogicalKeyboardKey.arrowUp, shift: true));
+    await tester.pump();
+    expect(paragraph1.selections.length, 1);
+    expect(paragraph1.selections[0].start, 2);
+    expect(paragraph1.selections[0].end, 7);
+    expect(paragraph2.selections.length, 0);
+    expect(paragraph3.selections.length, 0);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'w are');
+
+    await sendKeyCombination(tester, const SingleActivator(LogicalKeyboardKey.arrowUp, shift: true));
+    await tester.pump();
+    expect(paragraph1.selections.length, 1);
+    expect(paragraph1.selections[0].start, 0);
+    expect(paragraph1.selections[0].end, 2);
+    expect(paragraph2.selections.length, 0);
+    expect(paragraph3.selections.length, 0);
+    expect(content, isNotNull);
+    expect(content!.plainText, 'Ho');
   });
 
   group('BrowserContextMenu', () {