refa persistent header & dynamic sliver appbar

Signed-off-by: dom <githubaccount56556@proton.me>

lib/common/widgets/dynamic_sliver_app_bar/dynamic_sliver_app_bar.dart

@@ -0,0 +1,357 @@
+/*
+ * This file is part of PiliPlus
+ *
+ * PiliPlus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PiliPlus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with PiliPlus.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import 'dart:math' as math;
+
+import 'package:PiliPlus/common/widgets/dynamic_sliver_app_bar/redering/sliver_persistent_header.dart';
+import 'package:PiliPlus/common/widgets/dynamic_sliver_app_bar/sliver_persistent_header.dart';
+import 'package:PiliPlus/common/widgets/only_layout_widget.dart'
+    show LayoutCallback;
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart'
+    hide SliverPersistentHeader, SliverPersistentHeaderDelegate;
+import 'package:flutter/services.dart';
+
+/// ref [SliverAppBar]
+class _SliverAppBarDelegate extends SliverPersistentHeaderDelegate {
+  _SliverAppBarDelegate({
+    required this.leading,
+    required this.automaticallyImplyLeading,
+    required this.title,
+    required this.actions,
+    required this.automaticallyImplyActions,
+    required this.flexibleSpace,
+    required this.bottom,
+    required this.elevation,
+    required this.scrolledUnderElevation,
+    required this.shadowColor,
+    required this.surfaceTintColor,
+    required this.forceElevated,
+    required this.backgroundColor,
+    required this.foregroundColor,
+    required this.iconTheme,
+    required this.actionsIconTheme,
+    required this.primary,
+    required this.centerTitle,
+    required this.excludeHeaderSemantics,
+    required this.titleSpacing,
+    required this.collapsedHeight,
+    required this.topPadding,
+    required this.shape,
+    required this.toolbarHeight,
+    required this.leadingWidth,
+    required this.toolbarTextStyle,
+    required this.titleTextStyle,
+    required this.systemOverlayStyle,
+    required this.forceMaterialTransparency,
+    required this.useDefaultSemanticsOrder,
+    required this.clipBehavior,
+    required this.accessibleNavigation,
+    required this.actionsPadding,
+  }) : assert(primary || topPadding == 0.0),
+       _bottomHeight = bottom?.preferredSize.height ?? 0.0;
+
+  final Widget? leading;
+  final bool automaticallyImplyLeading;
+  final Widget title;
+  final List<Widget>? actions;
+  final bool automaticallyImplyActions;
+  final Widget flexibleSpace;
+  final PreferredSizeWidget? bottom;
+  final double? elevation;
+  final double? scrolledUnderElevation;
+  final Color? shadowColor;
+  final Color? surfaceTintColor;
+  final bool forceElevated;
+  final Color? backgroundColor;
+  final Color? foregroundColor;
+  final IconThemeData? iconTheme;
+  final IconThemeData? actionsIconTheme;
+  final bool primary;
+  final bool? centerTitle;
+  final bool excludeHeaderSemantics;
+  final double? titleSpacing;
+  final double collapsedHeight;
+  final double topPadding;
+  final ShapeBorder? shape;
+  final double? toolbarHeight;
+  final double? leadingWidth;
+  final TextStyle? toolbarTextStyle;
+  final TextStyle? titleTextStyle;
+  final SystemUiOverlayStyle? systemOverlayStyle;
+  final double _bottomHeight;
+  final bool forceMaterialTransparency;
+  final bool useDefaultSemanticsOrder;
+  final Clip? clipBehavior;
+  final bool accessibleNavigation;
+  final EdgeInsetsGeometry? actionsPadding;
+
+  @override
+  double get minExtent => collapsedHeight;
+
+  @override
+  Widget build(
+    BuildContext context,
+    double shrinkOffset,
+    bool overlapsContent,
+    double? maxExtent,
+  ) {
+    maxExtent ??= double.infinity;
+    final bool isScrolledUnder =
+        overlapsContent ||
+        forceElevated ||
+        (shrinkOffset > maxExtent - minExtent);
+    final effectiveTitle = AnimatedOpacity(
+      opacity: isScrolledUnder ? 1 : 0,
+      duration: const Duration(milliseconds: 500),
+      curve: const Cubic(0.2, 0.0, 0.0, 1.0),
+      child: title,
+    );
+
+    return FlexibleSpaceBar.createSettings(
+      minExtent: minExtent,
+      maxExtent: maxExtent,
+      currentExtent: math.max(minExtent, maxExtent - shrinkOffset),
+      isScrolledUnder: isScrolledUnder,
+      hasLeading: leading != null || automaticallyImplyLeading,
+      child: AppBar(
+        clipBehavior: clipBehavior,
+        leading: leading,
+        automaticallyImplyLeading: automaticallyImplyLeading,
+        title: effectiveTitle,
+        actions: actions,
+        automaticallyImplyActions: automaticallyImplyActions,
+        flexibleSpace: maxExtent == .infinity
+            ? flexibleSpace
+            : FlexibleSpaceBar(background: flexibleSpace),
+        bottom: bottom,
+        elevation: isScrolledUnder ? elevation : 0.0,
+        scrolledUnderElevation: scrolledUnderElevation,
+        shadowColor: shadowColor,
+        surfaceTintColor: surfaceTintColor,
+        backgroundColor: backgroundColor,
+        foregroundColor: foregroundColor,
+        iconTheme: iconTheme,
+        actionsIconTheme: actionsIconTheme,
+        primary: primary,
+        centerTitle: centerTitle,
+        excludeHeaderSemantics: excludeHeaderSemantics,
+        titleSpacing: titleSpacing,
+        shape: shape,
+        toolbarHeight: toolbarHeight,
+        leadingWidth: leadingWidth,
+        toolbarTextStyle: toolbarTextStyle,
+        titleTextStyle: titleTextStyle,
+        systemOverlayStyle: systemOverlayStyle,
+        forceMaterialTransparency: forceMaterialTransparency,
+        useDefaultSemanticsOrder: useDefaultSemanticsOrder,
+        actionsPadding: actionsPadding,
+      ),
+    );
+  }
+
+  @override
+  bool shouldRebuild(covariant _SliverAppBarDelegate oldDelegate) {
+    return leading != oldDelegate.leading ||
+        automaticallyImplyLeading != oldDelegate.automaticallyImplyLeading ||
+        title != oldDelegate.title ||
+        actions != oldDelegate.actions ||
+        automaticallyImplyActions != oldDelegate.automaticallyImplyActions ||
+        flexibleSpace != oldDelegate.flexibleSpace ||
+        bottom != oldDelegate.bottom ||
+        _bottomHeight != oldDelegate._bottomHeight ||
+        elevation != oldDelegate.elevation ||
+        shadowColor != oldDelegate.shadowColor ||
+        backgroundColor != oldDelegate.backgroundColor ||
+        foregroundColor != oldDelegate.foregroundColor ||
+        iconTheme != oldDelegate.iconTheme ||
+        actionsIconTheme != oldDelegate.actionsIconTheme ||
+        primary != oldDelegate.primary ||
+        centerTitle != oldDelegate.centerTitle ||
+        titleSpacing != oldDelegate.titleSpacing ||
+        topPadding != oldDelegate.topPadding ||
+        forceElevated != oldDelegate.forceElevated ||
+        toolbarHeight != oldDelegate.toolbarHeight ||
+        leadingWidth != oldDelegate.leadingWidth ||
+        toolbarTextStyle != oldDelegate.toolbarTextStyle ||
+        titleTextStyle != oldDelegate.titleTextStyle ||
+        systemOverlayStyle != oldDelegate.systemOverlayStyle ||
+        forceMaterialTransparency != oldDelegate.forceMaterialTransparency ||
+        useDefaultSemanticsOrder != oldDelegate.useDefaultSemanticsOrder ||
+        accessibleNavigation != oldDelegate.accessibleNavigation ||
+        actionsPadding != oldDelegate.actionsPadding;
+  }
+
+  @override
+  String toString() {
+    return '${describeIdentity(this)}(topPadding: ${topPadding.toStringAsFixed(1)}, bottomHeight: ${_bottomHeight.toStringAsFixed(1)}, ...)';
+  }
+}
+
+class DynamicSliverAppBar extends StatefulWidget {
+  const DynamicSliverAppBar.medium({
+    super.key,
+    this.leading,
+    this.automaticallyImplyLeading = true,
+    required this.title,
+    this.actions,
+    this.automaticallyImplyActions = true,
+    required this.flexibleSpace,
+    this.bottom,
+    this.elevation,
+    this.scrolledUnderElevation,
+    this.shadowColor,
+    this.surfaceTintColor,
+    this.forceElevated = false,
+    this.backgroundColor,
+    this.foregroundColor,
+    this.iconTheme,
+    this.actionsIconTheme,
+    this.primary = true,
+    this.centerTitle,
+    this.excludeHeaderSemantics = false,
+    this.titleSpacing,
+    this.shape,
+    this.leadingWidth,
+    this.toolbarTextStyle,
+    this.titleTextStyle,
+    this.systemOverlayStyle,
+    this.forceMaterialTransparency = false,
+    this.useDefaultSemanticsOrder = true,
+    this.clipBehavior,
+    this.actionsPadding,
+    this.onPerformLayout,
+  });
+
+  final LayoutCallback? onPerformLayout;
+
+  final Widget? leading;
+
+  final bool automaticallyImplyLeading;
+
+  final Widget title;
+
+  final List<Widget>? actions;
+
+  final bool automaticallyImplyActions;
+
+  final Widget flexibleSpace;
+
+  final PreferredSizeWidget? bottom;
+
+  final double? elevation;
+
+  final double? scrolledUnderElevation;
+
+  final Color? shadowColor;
+
+  final Color? surfaceTintColor;
+
+  final bool forceElevated;
+
+  final Color? backgroundColor;
+
+  final Color? foregroundColor;
+
+  final IconThemeData? iconTheme;
+
+  final IconThemeData? actionsIconTheme;
+
+  final bool primary;
+
+  final bool? centerTitle;
+
+  final bool excludeHeaderSemantics;
+
+  final double? titleSpacing;
+
+  final ShapeBorder? shape;
+
+  final double? leadingWidth;
+
+  final TextStyle? toolbarTextStyle;
+
+  final TextStyle? titleTextStyle;
+
+  final SystemUiOverlayStyle? systemOverlayStyle;
+
+  final bool forceMaterialTransparency;
+
+  final bool useDefaultSemanticsOrder;
+
+  final Clip? clipBehavior;
+
+  final EdgeInsetsGeometry? actionsPadding;
+
+  @override
+  State<DynamicSliverAppBar> createState() => _DynamicSliverAppBarState();
+}
+
+class _DynamicSliverAppBarState extends State<DynamicSliverAppBar> {
+  @override
+  Widget build(BuildContext context) {
+    final double bottomHeight = widget.bottom?.preferredSize.height ?? 0.0;
+    final double topPadding = widget.primary
+        ? MediaQuery.viewPaddingOf(context).top
+        : 0.0;
+    final double effectiveCollapsedHeight =
+        topPadding + kToolbarHeight + bottomHeight + 1;
+
+    return MediaQuery.removePadding(
+      context: context,
+      removeBottom: true,
+      child: SliverPinnedHeader(
+        onPerformLayout: widget.onPerformLayout,
+        delegate: _SliverAppBarDelegate(
+          leading: widget.leading,
+          automaticallyImplyLeading: widget.automaticallyImplyLeading,
+          title: widget.title,
+          actions: widget.actions,
+          automaticallyImplyActions: widget.automaticallyImplyActions,
+          flexibleSpace: widget.flexibleSpace,
+          bottom: widget.bottom,
+          elevation: widget.elevation,
+          scrolledUnderElevation: widget.scrolledUnderElevation,
+          shadowColor: widget.shadowColor,
+          surfaceTintColor: widget.surfaceTintColor,
+          forceElevated: widget.forceElevated,
+          backgroundColor: widget.backgroundColor,
+          foregroundColor: widget.foregroundColor,
+          iconTheme: widget.iconTheme,
+          actionsIconTheme: widget.actionsIconTheme,
+          primary: widget.primary,
+          centerTitle: widget.centerTitle,
+          excludeHeaderSemantics: widget.excludeHeaderSemantics,
+          titleSpacing: widget.titleSpacing,
+          collapsedHeight: effectiveCollapsedHeight,
+          topPadding: topPadding,
+          shape: widget.shape,
+          toolbarHeight: kToolbarHeight,
+          leadingWidth: widget.leadingWidth,
+          toolbarTextStyle: widget.toolbarTextStyle,
+          titleTextStyle: widget.titleTextStyle,
+          systemOverlayStyle: widget.systemOverlayStyle,
+          forceMaterialTransparency: widget.forceMaterialTransparency,
+          useDefaultSemanticsOrder: widget.useDefaultSemanticsOrder,
+          clipBehavior: widget.clipBehavior,
+          accessibleNavigation: MediaQuery.of(context).accessibleNavigation,
+          actionsPadding: widget.actionsPadding,
+        ),
+      ),
+    );
+  }
+}

lib/common/widgets/dynamic_sliver_app_bar/redering/sliver_persistent_header.dart

@@ -0,0 +1,285 @@
+/*
+ * This file is part of PiliPlus
+ *
+ * PiliPlus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PiliPlus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with PiliPlus.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import 'dart:math' as math;
+
+import 'package:PiliPlus/common/widgets/dynamic_sliver_app_bar/sliver_persistent_header.dart';
+import 'package:PiliPlus/common/widgets/only_layout_widget.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/rendering.dart' hide LayoutCallback;
+import 'package:flutter/widgets.dart'
+    hide SliverPersistentHeader, SliverPersistentHeaderDelegate;
+
+/// ref [SliverPersistentHeader]
+
+Rect? _trim(
+  Rect? original, {
+  double top = -double.infinity,
+  double right = double.infinity,
+  double bottom = double.infinity,
+  double left = -double.infinity,
+}) => original?.intersect(Rect.fromLTRB(left, top, right, bottom));
+
+abstract class RenderSliverPersistentHeader extends RenderSliver
+    with RenderObjectWithChildMixin<RenderBox>, RenderSliverHelpers {
+  RenderSliverPersistentHeader({RenderBox? child}) {
+    this.child = child;
+  }
+
+  SliverPersistentHeaderElement? element;
+
+  double get minExtent =>
+      (element!.widget as SliverPinnedHeader).delegate.minExtent;
+
+  bool _needsUpdateChild = true;
+
+  double get lastShrinkOffset => _lastShrinkOffset;
+  double _lastShrinkOffset = 0.0;
+
+  bool get lastOverlapsContent => _lastOverlapsContent;
+  bool _lastOverlapsContent = false;
+
+  @protected
+  void updateChild(
+    double shrinkOffset,
+    bool overlapsContent,
+    double? maxExtent,
+  ) {
+    assert(element != null);
+    element!.build(shrinkOffset, overlapsContent, maxExtent);
+  }
+
+  @override
+  void markNeedsLayout() {
+    _needsUpdateChild = true;
+    super.markNeedsLayout();
+  }
+
+  @protected
+  void updateChildIfNeeded(
+    double scrollOffset,
+    double? maxExtent, {
+    bool overlapsContent = false,
+  }) {
+    final double shrinkOffset = maxExtent == null
+        ? scrollOffset
+        : math.min(scrollOffset, maxExtent);
+    if (_needsUpdateChild ||
+        _lastShrinkOffset != shrinkOffset ||
+        _lastOverlapsContent != overlapsContent) {
+      invokeLayoutCallback<SliverConstraints>((SliverConstraints constraints) {
+        assert(constraints == this.constraints);
+        updateChild(shrinkOffset, overlapsContent, maxExtent);
+      });
+      _lastShrinkOffset = shrinkOffset;
+      _lastOverlapsContent = overlapsContent;
+      _needsUpdateChild = false;
+    }
+  }
+
+  @override
+  double childMainAxisPosition(covariant RenderObject child) =>
+      super.childMainAxisPosition(child);
+
+  @override
+  bool hitTestChildren(
+    SliverHitTestResult result, {
+    required double mainAxisPosition,
+    required double crossAxisPosition,
+  }) {
+    assert(geometry!.hitTestExtent > 0.0);
+    if (child != null) {
+      return hitTestBoxChild(
+        BoxHitTestResult.wrap(result),
+        child!,
+        mainAxisPosition: mainAxisPosition,
+        crossAxisPosition: crossAxisPosition,
+      );
+    }
+    return false;
+  }
+
+  @override
+  void applyPaintTransform(RenderObject child, Matrix4 transform) {
+    assert(child == this.child);
+    applyPaintTransformForBoxChild(child as RenderBox, transform);
+  }
+
+  void triggerRebuild() {
+    markNeedsLayout();
+  }
+}
+
+class SliverPinnedHeader extends RenderObjectWidget {
+  const SliverPinnedHeader({
+    super.key,
+    required this.delegate,
+    this.onPerformLayout,
+  });
+
+  final SliverPersistentHeaderDelegate delegate;
+  final LayoutCallback? onPerformLayout;
+
+  @override
+  SliverPersistentHeaderElement createElement() =>
+      SliverPersistentHeaderElement(this);
+
+  @override
+  RenderSliverPinnedHeader createRenderObject(BuildContext context) {
+    return RenderSliverPinnedHeader(onPerformLayout: onPerformLayout);
+  }
+
+  @override
+  void updateRenderObject(
+    BuildContext context,
+    RenderSliverPinnedHeader renderObject,
+  ) {
+    renderObject.onPerformLayout = onPerformLayout;
+  }
+}
+
+class RenderSliverPinnedHeader extends RenderSliverPersistentHeader {
+  RenderSliverPinnedHeader({
+    super.child,
+    this.onPerformLayout,
+  });
+
+  LayoutCallback? onPerformLayout;
+
+  ({double crossAxisExtent, double maxExtent})? _maxExtent;
+  double? get maxExtent => _maxExtent?.maxExtent;
+
+  void _rawLayout() {
+    child!.layout(constraints.asBoxConstraints(), parentUsesSize: true);
+    _maxExtent = (
+      crossAxisExtent: constraints.crossAxisExtent,
+      maxExtent: child!.size.height,
+    );
+    onPerformLayout?.call(child!.size);
+  }
+
+  void _layout() {
+    final double shrinkOffset = math.min(
+      constraints.scrollOffset,
+      _maxExtent!.maxExtent,
+    );
+    child!.layout(
+      constraints.asBoxConstraints(
+        maxExtent: math.max(minExtent, _maxExtent!.maxExtent - shrinkOffset),
+      ),
+      parentUsesSize: true,
+    );
+  }
+
+  @override
+  void performLayout() {
+    final constraints = this.constraints;
+    final bool overlapsContent = constraints.overlap > 0.0;
+
+    if (_maxExtent == null) {
+      updateChildIfNeeded(
+        constraints.scrollOffset,
+        _maxExtent?.maxExtent,
+        overlapsContent: overlapsContent,
+      );
+      _rawLayout();
+    } else {
+      if (_maxExtent!.crossAxisExtent == constraints.crossAxisExtent) {
+        updateChildIfNeeded(
+          constraints.scrollOffset,
+          _maxExtent?.maxExtent,
+          overlapsContent: overlapsContent,
+        );
+        _layout();
+      } else {
+        _needsUpdateChild = true;
+        updateChildIfNeeded(
+          constraints.scrollOffset,
+          null,
+          overlapsContent: overlapsContent,
+        );
+        _rawLayout();
+        if (constraints.scrollOffset > 0.0) {
+          _needsUpdateChild = true;
+          updateChildIfNeeded(
+            constraints.scrollOffset,
+            _maxExtent?.maxExtent,
+            overlapsContent: overlapsContent,
+          );
+          _layout();
+        }
+      }
+    }
+    final childExtent = child!.size.height;
+    final maxExtent = _maxExtent!.maxExtent;
+    final double effectiveRemainingPaintExtent = math.max(
+      0,
+      constraints.remainingPaintExtent - constraints.overlap,
+    );
+    final double layoutExtent = clampDouble(
+      maxExtent - constraints.scrollOffset,
+      0.0,
+      effectiveRemainingPaintExtent,
+    );
+    geometry = SliverGeometry(
+      scrollExtent: maxExtent,
+      paintOrigin: constraints.overlap,
+      paintExtent: math.min(childExtent, effectiveRemainingPaintExtent),
+      layoutExtent: layoutExtent,
+      maxPaintExtent: maxExtent,
+      maxScrollObstructionExtent: minExtent,
+      cacheExtent: layoutExtent > 0.0
+          ? -constraints.cacheOrigin + layoutExtent
+          : layoutExtent,
+      hasVisualOverflow: false,
+    );
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    if (child != null && geometry!.visible) {
+      context.paintChild(child!, offset);
+    }
+  }
+
+  @override
+  double childMainAxisPosition(RenderBox child) => 0.0;
+
+  @override
+  void showOnScreen({
+    RenderObject? descendant,
+    Rect? rect,
+    Duration duration = Duration.zero,
+    Curve curve = Curves.ease,
+  }) {
+    final Rect? localBounds = descendant != null
+        ? MatrixUtils.transformRect(
+            descendant.getTransformTo(this),
+            rect ?? descendant.paintBounds,
+          )
+        : rect;
+
+    final Rect? newRect = _trim(localBounds, top: 0);
+
+    super.showOnScreen(
+      descendant: this,
+      rect: newRect,
+      duration: duration,
+      curve: curve,
+    );
+  }
+}

lib/common/widgets/dynamic_sliver_app_bar/sliver_persistent_header.dart

@@ -0,0 +1,148 @@
+/*
+ * This file is part of PiliPlus
+ *
+ * PiliPlus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PiliPlus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with PiliPlus.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import 'package:PiliPlus/common/widgets/dynamic_sliver_app_bar/redering/sliver_persistent_header.dart';
+import 'package:flutter/widgets.dart';
+
+/// ref [SliverPersistentHeader]
+
+abstract class SliverPersistentHeaderDelegate {
+  const SliverPersistentHeaderDelegate();
+
+  Widget build(
+    BuildContext context,
+    double shrinkOffset,
+    bool overlapsContent,
+    double? maxExtent,
+  );
+
+  double get minExtent;
+
+  bool shouldRebuild(covariant SliverPersistentHeaderDelegate oldDelegate);
+}
+
+class SliverPersistentHeaderElement extends RenderObjectElement {
+  SliverPersistentHeaderElement(
+    SliverPinnedHeader super.widget,
+  );
+
+  @override
+  RenderSliverPinnedHeader get renderObject =>
+      super.renderObject as RenderSliverPinnedHeader;
+
+  @override
+  void mount(Element? parent, Object? newSlot) {
+    super.mount(parent, newSlot);
+    renderObject.element = this;
+  }
+
+  @override
+  void unmount() {
+    renderObject.element = null;
+    super.unmount();
+  }
+
+  @override
+  void update(SliverPinnedHeader newWidget) {
+    final oldWidget = widget as SliverPinnedHeader;
+    super.update(newWidget);
+    final SliverPersistentHeaderDelegate newDelegate = newWidget.delegate;
+    final SliverPersistentHeaderDelegate oldDelegate = oldWidget.delegate;
+    if (newDelegate != oldDelegate &&
+        (newDelegate.runtimeType != oldDelegate.runtimeType ||
+            newDelegate.shouldRebuild(oldDelegate))) {
+      final RenderSliverPinnedHeader renderObject = this.renderObject;
+      _updateChild(
+        newDelegate,
+        renderObject.lastShrinkOffset,
+        renderObject.lastOverlapsContent,
+        renderObject.maxExtent,
+      );
+      renderObject.triggerRebuild();
+    }
+  }
+
+  @override
+  void performRebuild() {
+    super.performRebuild();
+    renderObject.triggerRebuild();
+  }
+
+  Element? child;
+
+  void _updateChild(
+    SliverPersistentHeaderDelegate delegate,
+    double shrinkOffset,
+    bool overlapsContent,
+    double? maxExtent,
+  ) {
+    final Widget newWidget = delegate.build(
+      this,
+      shrinkOffset,
+      overlapsContent,
+      maxExtent,
+    );
+    child = updateChild(child, newWidget, null);
+  }
+
+  void build(double shrinkOffset, bool overlapsContent, double? maxExtent) {
+    owner!.buildScope(this, () {
+      final sliverPersistentHeaderRenderObjectWidget =
+          widget as SliverPinnedHeader;
+      _updateChild(
+        sliverPersistentHeaderRenderObjectWidget.delegate,
+        shrinkOffset,
+        overlapsContent,
+        maxExtent,
+      );
+    });
+  }
+
+  @override
+  void forgetChild(Element child) {
+    assert(child == this.child);
+    this.child = null;
+    super.forgetChild(child);
+  }
+
+  @override
+  void insertRenderObjectChild(covariant RenderBox child, Object? slot) {
+    assert(renderObject.debugValidateChild(child));
+    renderObject.child = child;
+  }
+
+  @override
+  void moveRenderObjectChild(
+    covariant RenderObject child,
+    Object? oldSlot,
+    Object? newSlot,
+  ) {
+    assert(false);
+  }
+
+  @override
+  void removeRenderObjectChild(covariant RenderObject child, Object? slot) {
+    renderObject.child = null;
+  }
+
+  @override
+  void visitChildren(ElementVisitor visitor) {
+    if (child != null) {
+      visitor(child!);
+    }
+  }
+}