refa persistent header & dynamic sliver appbar

Signed-off-by: dom <githubaccount56556@proton.me>
2026-04-20 11:08:03 +08:00 · 2026-03-02 16:16:17 +08:00
parent 1dbc54f063
commit 9c7b18710c
30 changed files with 1691 additions and 883 deletions
--- a/lib/common/widgets/sliver/sliver_pinned_header.dart
+++ b/lib/common/widgets/sliver/sliver_pinned_header.dart
@@ -0,0 +1,118 @@
+/*
+ * 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:flutter/foundation.dart' show clampDouble;
+import 'package:flutter/rendering.dart'
+    show RenderSliverSingleBoxAdapter, SliverGeometry;
+import 'package:flutter/widgets.dart';
+
+/// ref [SliverPersistentHeader]
+class SliverPinnedHeader extends SingleChildRenderObjectWidget {
+  const SliverPinnedHeader({
+    super.key,
+    required Widget super.child,
+    this.backgroundColor,
+  });
+
+  final Color? backgroundColor;
+
+  @override
+  RenderObject createRenderObject(BuildContext context) =>
+      RenderSliverPinnedHeader(backgroundColor: backgroundColor);
+
+  @override
+  void updateRenderObject(
+    BuildContext context,
+    RenderSliverPinnedHeader renderObject,
+  ) {
+    renderObject.backgroundColor = backgroundColor;
+  }
+}
+
+class RenderSliverPinnedHeader extends RenderSliverSingleBoxAdapter {
+  RenderSliverPinnedHeader({
+    required Color? backgroundColor,
+  }) : _backgroundColor = backgroundColor;
+
+  Color? _backgroundColor;
+  set backgroundColor(Color? value) {
+    if (_backgroundColor == value) return;
+    _backgroundColor = value;
+    if (_isPinned) markNeedsPaint();
+  }
+
+  bool _isPinned = false;
+
+  @override
+  void performLayout() {
+    final constraints = this.constraints;
+    child!.layout(constraints.asBoxConstraints(), parentUsesSize: true);
+    final double childExtent = child!.size.height;
+    final double effectiveRemainingPaintExtent = math.max(
+      0,
+      constraints.remainingPaintExtent - constraints.overlap,
+    );
+    final double layoutExtent = clampDouble(
+      childExtent - constraints.scrollOffset,
+      0.0,
+      effectiveRemainingPaintExtent,
+    );
+    _isPinned = constraints.overlap > 0.0 || constraints.scrollOffset > 0.0;
+    geometry = SliverGeometry(
+      scrollExtent: childExtent,
+      paintOrigin: constraints.overlap,
+      paintExtent: math.min(childExtent, effectiveRemainingPaintExtent),
+      layoutExtent: layoutExtent,
+      maxPaintExtent: childExtent,
+      maxScrollObstructionExtent: childExtent,
+      cacheExtent: layoutExtent > 0.0
+          ? -constraints.cacheOrigin + layoutExtent
+          : layoutExtent,
+      hasVisualOverflow: false,
+    );
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    if (child != null && geometry!.visible) {
+      if (_isPinned && _backgroundColor != null) {
+        final size = child!.size;
+        context.canvas.drawRect(
+          Rect.fromLTWH(
+            offset.dx,
+            offset.dy - 2,
+            size.width,
+            size.height + 2,
+          ),
+          Paint()..color = _backgroundColor!,
+        );
+      }
+      context.paintChild(child!, offset);
+    }
+  }
+
+  @override
+  double childMainAxisPosition(RenderBox child) => 0.0;
+
+  @override
+  bool hitTestSelf({
+    required double mainAxisPosition,
+    required double crossAxisPosition,
+  }) => true;
+}