Blinking cursor respects TickerMode (#92614)

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

@@ -1674,6 +1674,10 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     _cursorVisibilityNotifier.value = widget.showCursor;
   }
 
+  // Whether `TickerMode.of(context)` is true and animations (like blinking the
+  // cursor) are supposed to run.
+  bool _tickersEnabled = true;
+
   @override
   void didChangeDependencies() {
     super.didChangeDependencies();
@@ -1693,6 +1697,19 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
         }
       });
     }
+
+    // Restart or stop the blinking cursor when TickerMode changes.
+    final bool newTickerEnabled = TickerMode.of(context);
+    if (_tickersEnabled != newTickerEnabled) {
+      _tickersEnabled = newTickerEnabled;
+      if (_tickersEnabled && _cursorActive) {
+        _startCursorTimer();
+      } else if (!_tickersEnabled && _cursorTimer != null) {
+        // Cannot use _stopCursorTimer because it would reset _cursorActive.
+        _cursorTimer!.cancel();
+        _cursorTimer = null;
+      }
+    }
   }
 
   @override
@@ -2535,8 +2552,16 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     _cursorTimer = Timer.periodic(_kCursorBlinkHalfPeriod, _cursorTick);
   }
 
+  // Indicates whether the cursor should be blinking right now (but it may
+  // actually not blink because it's disabled via TickerMode.of(context)).
+  bool _cursorActive = false;
+
   void _startCursorTimer() {
     assert(_cursorTimer == null);
+    _cursorActive = true;
+    if (!_tickersEnabled) {
+      return;
+    }
     _targetCursorVisibility = true;
     _cursorBlinkOpacityController.value = 1.0;
     if (EditableText.debugDeterministicCursor)
@@ -2549,6 +2574,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   void _stopCursorTimer({ bool resetCharTicks = true }) {
+    _cursorActive = false;
     _cursorTimer?.cancel();
     _cursorTimer = null;
     _targetCursorVisibility = false;
@@ -2566,7 +2592,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   void _startOrStopCursorTimerIfNeeded() {
     if (_cursorTimer == null && _hasFocus && _value.selection.isCollapsed)
       _startCursorTimer();
-    else if (_cursorTimer != null && (!_hasFocus || !_value.selection.isCollapsed))
+    else if (_cursorActive && (!_hasFocus || !_value.selection.isCollapsed))
       _stopCursorTimer();
   }
 

packages/flutter/test/material/text_field_test.dart

@@ -10036,4 +10036,84 @@ void main() {
 
     expect(tester.layers.any((Layer layer) => layer.debugSubtreeNeedsAddToScene!), isFalse);
   }, skip: isContextMenuProvidedByPlatform); // [intended] only applies to platforms where we supply the context menu.
+
+  testWidgets('cursor blinking respects TickerMode', (WidgetTester tester) async {
+    final FocusNode focusNode = FocusNode();
+    Widget builder({required bool tickerMode}) {
+      return MaterialApp(
+        home:  Material(
+          child: Center(
+            child: TickerMode(enabled: tickerMode, child: TextField(focusNode: focusNode)),
+          ),
+        ),
+      );
+    }
+
+    // TickerMode is on, cursor is blinking.
+    await tester.pumpWidget(builder(tickerMode: true));
+    await tester.showKeyboard(find.byType(TextField));
+    final EditableTextState state = tester.state<EditableTextState>(find.byType(EditableText));
+    final RenderEditable editable = state.renderEditable;
+    expect(editable.showCursor.value, isTrue);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isTrue);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+
+    // TickerMode is off, cursor does not blink.
+    await tester.pumpWidget(builder(tickerMode: false));
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+
+    // TickerMode is on, cursor blinks again.
+    await tester.pumpWidget(builder(tickerMode: true));
+    expect(editable.showCursor.value, isTrue);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isTrue);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+
+    // Dismissing focus while tickerMode is off does not start cursor blinking
+    // when tickerMode is turned on again.
+    await tester.pumpWidget(builder(tickerMode: false));
+    focusNode.unfocus();
+    await tester.pump();
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pumpWidget(builder(tickerMode: true));
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+
+    // Focusing while tickerMode is off does not start cursor blinking...
+    await tester.pumpWidget(builder(tickerMode: false));
+    await tester.showKeyboard(find.byType(TextField));
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+
+    // ... but it does start when tickerMode is switched on again.
+    await tester.pumpWidget(builder(tickerMode: true));
+    expect(editable.showCursor.value, isTrue);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isFalse);
+    await tester.pump(state.cursorBlinkInterval);
+    expect(editable.showCursor.value, isTrue);
+  });
 }