Configurable padding around FocusNodes in Scrollables (#96815)

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

@@ -759,6 +759,16 @@ class FocusNode with DiagnosticableTreeMixin, ChangeNotifier {
     return null;
   }
 
+  /// Returns the amount of additional space to reveal around the attached widget
+  /// when focused inside a scrolling container via [Scrollable.ensureVisible].
+  ///
+  /// For example, a value of `EdgeInsets.all(16.0)` ensures 16 pixels of
+  /// the adjacent widget are visible when this node receives focus.
+  ///
+  /// By default, this returns [FocusManager.defaultEnsureVisiblePadding] from the
+  /// associated [FocusManager], or [EdgeInsets.zero].
+  EdgeInsets get ensureVisiblePadding => _manager?.defaultEnsureVisiblePadding ?? EdgeInsets.zero;
+
   /// Returns the size of the attached widget's [RenderObject], in logical
   /// units.
   ///
@@ -1710,6 +1720,20 @@ class FocusManager with DiagnosticableTreeMixin, ChangeNotifier {
     return handled;
   }
 
+  /// The default amount of additonal space to reveal when a widget is focused
+  /// inside a scrolling container via [Scrollable.ensureVisible].
+  ///
+  /// Defaults to [EdgeInsets.zero], which does not add any additional space
+  /// when widgets are revealed.
+  ///
+  /// For example, a value of `EdgeInsets.all(16.0)` ensures 16 pixels of
+  /// the adjacent widget are visible when focusing a widget inside of a
+  /// scrolling container.
+  ///
+  /// Individual [FocusNode]s may increase or decrease this padding, use
+  /// [FocusNode.ensureVisiblePadding] to obtain a node's desired padding.
+  EdgeInsets defaultEnsureVisiblePadding = EdgeInsets.zero;
+
   /// The node that currently has the primary focus.
   FocusNode? get primaryFocus => _primaryFocus;
   FocusNode? _primaryFocus;

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

@@ -36,7 +36,7 @@ void _focusAndEnsureVisible(
   ScrollPositionAlignmentPolicy alignmentPolicy = ScrollPositionAlignmentPolicy.explicit,
 }) {
   node.requestFocus();
-  Scrollable.ensureVisible(node.context!, alignment: 1.0, alignmentPolicy: alignmentPolicy);
+  Scrollable.ensureVisible(node.context!, alignment: 1.0, padding: node.ensureVisiblePadding, alignmentPolicy: alignmentPolicy);
 }
 
 // A class to temporarily hold information about FocusTraversalGroups when

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

@@ -346,6 +346,7 @@ class _PagePosition extends ScrollPositionWithSingleContext implements PageMetri
   Future<void> ensureVisible(
     RenderObject object, {
     double alignment = 0.0,
+    EdgeInsets padding = EdgeInsets.zero,
     Duration duration = Duration.zero,
     Curve curve = Curves.ease,
     ScrollPositionAlignmentPolicy alignmentPolicy = ScrollPositionAlignmentPolicy.explicit,

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

@@ -676,6 +676,10 @@ abstract class ScrollPosition extends ViewportOffset with ScrollMetrics {
   /// Animates the position such that the given object is as visible as possible
   /// by just scrolling this position.
   ///
+  /// The [padding] is used to add extra space around the [object] when revealing it.
+  /// For example, `EdgeInsets.only(bottom: 16.0)` will ensure an additional 16 pixels
+  /// of space are visible below the [object].
+  ///
   /// The optional `targetRenderObject` parameter is used to determine which area
   /// of that object should be as visible as possible. If `targetRenderObject`
   /// is null, the entire [RenderObject] (as defined by its
@@ -686,9 +690,12 @@ abstract class ScrollPosition extends ViewportOffset with ScrollMetrics {
   ///
   ///  * [ScrollPositionAlignmentPolicy] for the way in which `alignment` is
   ///    applied, and the way the given `object` is aligned.
+  ///  * [FocusNode.ensureVisiblePadding] which specifies the [padding] used when
+  ///    a widget is focused via focus traversal.
   Future<void> ensureVisible(
     RenderObject object, {
     double alignment = 0.0,
+    EdgeInsets padding = EdgeInsets.zero,
     Duration duration = Duration.zero,
     Curve curve = Curves.ease,
     ScrollPositionAlignmentPolicy alignmentPolicy = ScrollPositionAlignmentPolicy.explicit,
@@ -699,14 +706,18 @@ abstract class ScrollPosition extends ViewportOffset with ScrollMetrics {
     final RenderAbstractViewport viewport = RenderAbstractViewport.of(object)!;
     assert(viewport != null);
 
-    Rect? targetRect;
+    Rect targetRect;
     if (targetRenderObject != null && targetRenderObject != object) {
       targetRect = MatrixUtils.transformRect(
         targetRenderObject.getTransformTo(object),
         object.paintBounds.intersect(targetRenderObject.paintBounds),
       );
+    } else {
+      targetRect = object.paintBounds;
     }
 
+    targetRect = padding.inflateRect(targetRect);
+
     double target;
     switch (alignmentPolicy) {
       case ScrollPositionAlignmentPolicy.explicit:

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

@@ -311,9 +311,19 @@ class Scrollable extends StatefulWidget {
 
   /// Scrolls the scrollables that enclose the given context so as to make the
   /// given context visible.
+  ///
+  /// The [padding] is used to add extra space around the [context]'s
+  /// associated widget when revealing it. For example, `EdgeInsets.only(bottom: 16.0)`
+  /// will ensure an additional 16 pixels of space are visible below the widget.
+  ///
+  /// See also:
+  ///
+  ///  * [FocusNode.ensureVisiblePadding] which specifies the [padding] used when
+  ///    a widget is focused via focus traversal.
   static Future<void> ensureVisible(
     BuildContext context, {
     double alignment = 0.0,
+    EdgeInsets padding = EdgeInsets.zero,
     Duration duration = Duration.zero,
     Curve curve = Curves.ease,
     ScrollPositionAlignmentPolicy alignmentPolicy = ScrollPositionAlignmentPolicy.explicit,
@@ -332,6 +342,7 @@ class Scrollable extends StatefulWidget {
       futures.add(scrollable.position.ensureVisible(
         context.findRenderObject()!,
         alignment: alignment,
+        padding: padding,
         duration: duration,
         curve: curve,
         alignmentPolicy: alignmentPolicy,