Make the cursor no longer blinking when move, as same as the effect of iOS platform. (#107221)

Author: talisk

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

@@ -2184,6 +2184,9 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
           _floatingCursorResetController!.stop();
           _onFloatingCursorResetTick();
         }
+        // Stop cursor blinking and making it visible.
+        _stopCursorBlink(resetCharTicks: false);
+        _cursorBlinkOpacityController.value = 1.0;
         // We want to send in points that are centered around a (0,0) origin, so
         // we cache the position.
         _pointOffsetOrigin = point.offset;
@@ -2204,6 +2207,8 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
         renderEditable.setFloatingCursor(point.state, _lastBoundedOffset!, _lastTextPosition!);
         break;
       case FloatingCursorDragState.End:
+        // Resume cursor blinking.
+        _startCursorBlink();
         // We skip animation if no update has happened.
         if (_lastTextPosition != null && _lastBoundedOffset != null) {
           _floatingCursorResetController!.value = 0.0;

packages/flutter/test/widgets/editable_text_cursor_test.dart

@@ -701,6 +701,73 @@ void main() {
     expect(tester.takeException(), null);
   });
 
+  testWidgets("Drag the floating cursor, it won't blink.", (WidgetTester tester) async {
+    const String text = 'hello world this is fun and cool and awesome!';
+    controller.text = text;
+    final FocusNode focusNode = FocusNode();
+
+    await tester.pumpWidget(
+      MediaQuery(
+        data: const MediaQueryData(),
+        child: Directionality(
+          textDirection: TextDirection.ltr,
+          child: FocusScope(
+            node: focusScopeNode,
+            autofocus: true,
+            child: EditableText(
+              backgroundCursorColor: Colors.grey,
+              controller: controller,
+              focusNode: focusNode,
+              style: textStyle,
+              cursorColor: cursorColor,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    final EditableTextState editableText = tester.state(find.byType(EditableText));
+
+    // Check that the cursor visibility toggles after each blink interval.
+    // Or if it's not blinking at all, it stays on.
+    Future<void> checkCursorBlinking({ bool isBlinking = true }) async {
+      bool initialShowCursor = true;
+      if (isBlinking) {
+        initialShowCursor = editableText.cursorCurrentlyVisible;
+      }
+      await tester.pump(editableText.cursorBlinkInterval);
+      expect(editableText.cursorCurrentlyVisible, equals(isBlinking ? !initialShowCursor : initialShowCursor));
+      await tester.pump(editableText.cursorBlinkInterval);
+      expect(editableText.cursorCurrentlyVisible, equals(initialShowCursor));
+      await tester.pump(editableText.cursorBlinkInterval ~/ 10);
+      expect(editableText.cursorCurrentlyVisible, equals(initialShowCursor));
+      await tester.pump(editableText.cursorBlinkInterval);
+      expect(editableText.cursorCurrentlyVisible, equals(isBlinking ? !initialShowCursor : initialShowCursor));
+      await tester.pump(editableText.cursorBlinkInterval);
+      expect(editableText.cursorCurrentlyVisible, equals(initialShowCursor));
+    }
+
+    final Offset textfieldStart = tester.getTopLeft(find.byType(EditableText));
+
+    await tester.tapAt(textfieldStart + const Offset(50.0, 9.0));
+    await tester.pumpAndSettle();
+
+    // Before dragging, the cursor should blink.
+    await checkCursorBlinking();
+
+    final EditableTextState editableTextState = tester.firstState(find.byType(EditableText));
+    editableTextState.updateFloatingCursor(RawFloatingCursorPoint(state: FloatingCursorDragState.Start));
+
+    // When drag cursor, the cursor shouldn't blink.
+    await checkCursorBlinking(isBlinking: false);
+
+    editableTextState.updateFloatingCursor(RawFloatingCursorPoint(state: FloatingCursorDragState.End));
+    await tester.pumpAndSettle();
+
+    // After dragging, the cursor should blink.
+    await checkCursorBlinking();
+  });
+
   // Regression test for https://github.com/flutter/flutter/pull/30475.
   testWidgets('Trying to select with the floating cursor does not crash', (WidgetTester tester) async {
     const String text = 'hello world this is fun and cool and awesome!';