Fixed cursor blinking during selection. (#141380)

The cursor now correctly stops blinking while it's being interacted with.

packages/flutter/lib/src/rendering/editable.dart

@@ -1193,6 +1193,8 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin,
   ///    in detail.
   EdgeInsets floatingCursorAddedMargin;
 
+  /// Returns true if the floating cursor is visible, false otherwise.
+  bool get floatingCursorOn => _floatingCursorOn;
   bool _floatingCursorOn = false;
   late TextPosition _floatingCursorTextPosition;
 

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

@@ -4166,7 +4166,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     _cursorVisibilityNotifier.value = widget.showCursor && (EditableText.debugDeterministicCursor || _cursorBlinkOpacityController.value > 0);
   }
 
-  bool get _showBlinkingCursor => _hasFocus && _value.selection.isCollapsed && widget.showCursor && _tickersEnabled;
+  bool get _showBlinkingCursor => _hasFocus && _value.selection.isCollapsed && widget.showCursor && _tickersEnabled && !renderEditable.floatingCursorOn;
 
   /// Whether the blinking cursor is actually visible at this precise moment
   /// (it's hidden half the time, since it blinks).
@@ -4230,7 +4230,9 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   void _stopCursorBlink({ bool resetCharTicks = true }) {
-    _cursorBlinkOpacityController.value = 0.0;
+    // If the cursor is animating, stop the animation, and we always
+    // want the cursor to be visible when the floating cursor is enabled.
+    _cursorBlinkOpacityController.value = renderEditable.floatingCursorOn ? 1.0 : 0.0;
     _cursorTimer?.cancel();
     _cursorTimer = null;
     if (resetCharTicks) {

packages/flutter/test/material/text_field_test.dart

@@ -17838,7 +17838,6 @@ void main() {
     skip: isContextMenuProvidedByPlatform, // [intended] only applies to platforms where we supply the context menu.
   );
 
-
   testWidgets('Start the floating cursor on long tap', (WidgetTester tester) async {
     EditableText.debugDeterministicCursor = true;
     final TextEditingController controller = _textEditingController(
@@ -17879,6 +17878,58 @@ void main() {
   },
     variant: TargetPlatformVariant.only(TargetPlatform.iOS),
   );
+
+  testWidgets('Cursor should not blink when long-pressing to show floating cursor.', (WidgetTester tester) async {
+    final TextEditingController controller = _textEditingController(
+      text: 'abcdefghijklmnopqr',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextField(
+              autofocus: true,
+              controller: controller,
+              cursorOpacityAnimates: false
+            )
+          ),
+        ),
+      ),
+    );
+    final EditableTextState state = tester.state(find.byType(EditableText));
+    Future<void> checkCursorBlinking({ bool isBlinking = true }) async {
+      bool initialShowCursor = true;
+      if (isBlinking) {
+        initialShowCursor = state.renderEditable.showCursor.value;
+      }
+      await tester.pump(state.cursorBlinkInterval);
+      expect(state.cursorCurrentlyVisible, equals(isBlinking ? !initialShowCursor : initialShowCursor));
+      await tester.pump(state.cursorBlinkInterval);
+      expect(state.cursorCurrentlyVisible, equals(initialShowCursor));
+      await tester.pump(state.cursorBlinkInterval);
+      expect(state.cursorCurrentlyVisible, equals(isBlinking ? !initialShowCursor : initialShowCursor));
+      await tester.pump(state.cursorBlinkInterval);
+      expect(state.cursorCurrentlyVisible, equals(initialShowCursor));
+    }
+    // Wait for autofocus.
+    await tester.pumpAndSettle();
+    // Before long-pressing, the cursor should blink.
+    await checkCursorBlinking();
+
+    final TestGesture gesture = await tester.startGesture(tester.getTopLeft(find.byType(TextField)));
+    await tester.pump(kLongPressTimeout);
+    // When long-pressing, the cursor shouldn't blink.
+    await checkCursorBlinking(isBlinking: false);
+    await gesture.moveBy(const Offset(20, 0));
+    await tester.pump();
+    // When long-pressing and dragging to move the cursor, the cursor shouldn't blink.
+    await checkCursorBlinking(isBlinking: false);
+    await gesture.up();
+    // After finishing the long-press, the cursor should blink.
+    await checkCursorBlinking();
+  },
+    variant: TargetPlatformVariant.only(TargetPlatform.iOS),
+  );
 }
 
 /// A Simple widget for testing the obscure text.