[SuperEditor] - Ignore spurious metrics change notification (#2127)

Author: knopp

super_editor/lib/src/default_editor/document_gestures_touch_android.dart

@@ -1,3 +1,4 @@
+import 'dart:ui';
 import 'dart:async';
 
 import 'package:flutter/foundation.dart';
@@ -471,6 +472,10 @@ class _AndroidDocumentTouchInteractorState extends State<AndroidDocumentTouchInt
 
   bool _isCaretDragInProgress = false;
 
+  // Cached view metrics to ignore unnecessary didChangeMetrics calls.
+  Size? _lastSize;
+  ViewPadding? _lastInsets;
+
   @override
   void initState() {
     super.initState();
@@ -494,6 +499,10 @@ class _AndroidDocumentTouchInteractorState extends State<AndroidDocumentTouchInt
   void didChangeDependencies() {
     super.didChangeDependencies();
 
+    final view = View.of(context);
+    _lastSize = view.physicalSize;
+    _lastInsets = view.viewInsets;
+
     _controlsController = SuperEditorAndroidControlsScope.rootOf(context);
 
     _ancestorScrollPosition = context.findAncestorScrollableWithVerticalScroll?.position;
@@ -529,6 +538,20 @@ class _AndroidDocumentTouchInteractorState extends State<AndroidDocumentTouchInt
 
   @override
   void didChangeMetrics() {
+    // It is possible to get the notification even though the metrics for view are same.
+    final view = View.of(context);
+    final size = view.physicalSize;
+    final insets = view.viewInsets;
+    if (size == _lastSize &&
+        _lastInsets?.left == insets.left &&
+        _lastInsets?.right == insets.right &&
+        _lastInsets?.top == insets.top &&
+        _lastInsets?.bottom == insets.bottom) {
+      return;
+    }
+    _lastSize = size;
+    _lastInsets = insets;
+
     // The available screen dimensions may have changed, e.g., due to keyboard
     // appearance/disappearance. Reflow the layout. Use a post-frame callback
     // to give the rest of the UI a chance to reflow, first.

super_editor/lib/src/default_editor/document_gestures_touch_ios.dart

@@ -1,3 +1,4 @@
+import 'dart:ui';
 import 'dart:async';
 
 import 'package:flutter/foundation.dart';
@@ -317,6 +318,10 @@ class _IosDocumentTouchInteractorState extends State<IosDocumentTouchInteractor>
   bool get _isLongPressInProgress => _longPressStrategy != null;
   IosLongPressSelectionStrategy? _longPressStrategy;
 
+  // Cached view metrics to ignore unnecessary didChangeMetrics calls.
+  Size? _lastSize;
+  ViewPadding? _lastInsets;
+
   @override
   void initState() {
     super.initState();
@@ -344,6 +349,10 @@ class _IosDocumentTouchInteractorState extends State<IosDocumentTouchInteractor>
   void didChangeDependencies() {
     super.didChangeDependencies();
 
+    final view = View.of(context);
+    _lastSize = view.physicalSize;
+    _lastInsets = view.viewInsets;
+
     if (_controlsController != null) {
       _controlsController!.floatingCursorController.removeListener(_floatingCursorListener);
       _controlsController!.floatingCursorController.cursorGeometryInViewport
@@ -407,6 +416,21 @@ class _IosDocumentTouchInteractorState extends State<IosDocumentTouchInteractor>
 
   @override
   void didChangeMetrics() {
+    // DidChangeMetrics is sometimes called even when metrics doesn't change
+    // (i.e. on iOS with keyboard visible)
+    final view = View.of(context);
+    final size = view.physicalSize;
+    final insets = view.viewInsets;
+    if (size == _lastSize &&
+        _lastInsets?.left == insets.left &&
+        _lastInsets?.right == insets.right &&
+        _lastInsets?.top == insets.top &&
+        _lastInsets?.bottom == insets.bottom) {
+      return;
+    }
+    _lastSize = size;
+    _lastInsets = insets;
+
     // The available screen dimensions may have changed, e.g., due to keyboard
     // appearance/disappearance. Ensure the extent is still visible. Use a
     // post-frame callback to give the rest of the UI a chance to reflow, first.

super_editor/test/super_editor/supereditor_scrolling_test.dart

@@ -1441,6 +1441,26 @@ void main() {
         findsNothing,
       );
     });
+
+    testWidgetsOnMobile('spurious metrics change is ignored', (tester) async {
+      final scrollController = ScrollController();
+      await tester //
+          .createDocument()
+          .withLongDoc()
+          .withEditorSize(const Size(300, 300))
+          .withScrollController(scrollController)
+          .pump();
+      await tester.tapInParagraph('1', 0);
+      final gesture = await tester.startGesture(Offset(100, 100), kind: PointerDeviceKind.touch);
+      await gesture.moveBy(Offset(0, -100));
+      await tester.pumpAndSettle();
+      final pixels = scrollController.position.pixels;
+      // This should not change scroll position.
+      WidgetsBinding.instance.handleMetricsChanged();
+      await Future.microtask(() {});
+      await tester.pump();
+      expect(scrollController.position.pixels, pixels);
+    });
   });
 }