Restart EditableText cursor timer when it moves (#70787)

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

@@ -2089,6 +2089,12 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
         ));
       }
     }
+
+    // To keep the cursor from blinking while it moves, restart the timer here.
+    if (_cursorTimer != null) {
+      _stopCursorTimer(resetCharTicks: false);
+      _startCursorTimer();
+    }
   }
 
   bool _textChangedSinceLastCaretUpdate = false;

packages/flutter/test/widgets/editable_text_cursor_test.dart

@@ -323,6 +323,81 @@ void main() {
     EditableText.debugDeterministicCursor = false;
   });
 
+  testWidgets('Cursor animation restarts when it is moved using keys on desktop', (WidgetTester tester) async {
+    const String testText = 'Some text long enough to move the cursor around';
+    final TextEditingController controller = TextEditingController(text: testText);
+    final Widget widget = MaterialApp(
+      home: EditableText(
+        controller: controller,
+        focusNode: FocusNode(),
+        style: const TextStyle(fontSize: 20.0),
+        maxLines: 1,
+        cursorColor: Colors.blue,
+        backgroundCursorColor: Colors.grey,
+        cursorOpacityAnimates: false,
+        selectionControls: materialTextSelectionControls,
+        keyboardType: TextInputType.text,
+        textAlign: TextAlign.left,
+      ),
+    );
+    await tester.pumpWidget(widget);
+
+    await tester.tap(find.byType(EditableText));
+    await tester.pump();
+
+    final EditableTextState editableTextState = tester.firstState(find.byType(EditableText));
+    final RenderEditable renderEditable = editableTextState.renderEditable;
+
+    await tester.pump();
+    expect(renderEditable.cursorColor!.alpha, 255);
+    expect(renderEditable, paints..rect(color: const Color(0xff2196f3)));
+
+    // Android cursor goes from exactly on to exactly off on the 500ms dot.
+    await tester.pump(const Duration(milliseconds: 499));
+    expect(renderEditable.cursorColor!.alpha, 255);
+    expect(renderEditable, paints..rect(color: const Color(0xff2196f3)));
+
+    await tester.sendKeyDownEvent(LogicalKeyboardKey.arrowLeft);
+    await tester.pump();
+    await tester.sendKeyUpEvent(LogicalKeyboardKey.arrowLeft);
+
+    await tester.pump();
+    expect(renderEditable.cursorColor!.alpha, 255);
+    expect(renderEditable, paints..rect(color: const Color(0xff2196f3)));
+
+    await tester.pump(const Duration(milliseconds: 200));
+    expect(renderEditable.cursorColor!.alpha, 255);
+    expect(renderEditable, paints..rect(color: const Color(0xff2196f3)));
+
+    await tester.pump(const Duration(milliseconds: 299));
+    expect(renderEditable.cursorColor!.alpha, 255);
+    expect(renderEditable, paints..rect(color: const Color(0xff2196f3)));
+
+    await tester.sendKeyDownEvent(LogicalKeyboardKey.arrowRight);
+    await tester.pump();
+    await tester.sendKeyUpEvent(LogicalKeyboardKey.arrowRight);
+    await tester.pump();
+    await tester.sendKeyDownEvent(LogicalKeyboardKey.arrowRight);
+    await tester.pump();
+    await tester.sendKeyUpEvent(LogicalKeyboardKey.arrowRight);
+
+    await tester.pump();
+    expect(renderEditable.cursorColor!.alpha, 255);
+    expect(renderEditable, paints..rect(color: const Color(0xff2196f3)));
+
+    await tester.pump(const Duration(milliseconds: 200));
+    expect(renderEditable.cursorColor!.alpha, 255);
+    expect(renderEditable, paints..rect(color: const Color(0xff2196f3)));
+
+    await tester.pump(const Duration(milliseconds: 299));
+    expect(renderEditable.cursorColor!.alpha, 255);
+    expect(renderEditable, paints..rect(color: const Color(0xff2196f3)));
+
+    await tester.pump(const Duration(milliseconds: 1));
+    expect(renderEditable.cursorColor!.alpha, 0);
+    expect(renderEditable, paintsExactlyCountTimes(#drawRect, 0));
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.macOS }));
+
   testWidgets('Cursor does not show when showCursor set to false', (WidgetTester tester) async {
     const Widget widget = MaterialApp(
       home: Material(