您可以向 sliverAppBar 添加一个形状
return Scaffold(
backgroundColor: Colors.orange,
body: CustomScrollView(
slivers: <Widget>[
SliverAppBar(
pinned: true,
floating: true,
expandedHeight: 250.0,
shape: RoundedRectangleBorder(
borderRadius:
BorderRadius.vertical(bottom: Radius.circular(16))), //like this
flexibleSpace: FlexibleSpaceBar(
background: Container(color: Colors.blueAccent), //changed it because I dont have the image asset
title: Text('Hello there')),
),
SliverGrid(
gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
maxCrossAxisExtent: 200.0,
mainAxisSpacing: 10.0,
crossAxisSpacing: 10.0,
childAspectRatio: 4.0,
),
delegate: SliverChildBuilderDelegate(
(BuildContext context, int index) {
return Container(
margin: EdgeInsets.symmetric(
horizontal: 15,
vertical: 15,
),
alignment: Alignment.center,
color: Colors.teal[100 * (index % 9)],
child: Text('grid item $index'),
);
},
childCount: 100,
),
),
],
),
);
}
如果你想要它的另一种方式，也许你应该创建一个自定义 ShapeBorder 并覆盖 getOuterPath 以超出形状并使其看起来像橙色的一侧是带有形状的一侧。让我知道您是否希望以这种方式尝试更新答案
更新
我相信你正在寻找这样的东西
class MyWidget extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.orange,
body: CustomScrollView(
slivers: <Widget>[
SliverAppBar(
pinned: true,
floating: true,
expandedHeight: 250.0,
shape: _CustomShape(), //like this
flexibleSpace: FlexibleSpaceBar(
background: Image.network(
"https://images.pexels.com/photos/396547/pexels-photo-396547.jpeg?auto=compress&cs=tinysrgb&h=350",
fit: BoxFit.cover,
),
title: Text('Hello there'),
),
),
SliverGrid(
gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
maxCrossAxisExtent: 200.0,
mainAxisSpacing: 10.0,
crossAxisSpacing: 10.0,
childAspectRatio: 4.0,
),
delegate: SliverChildBuilderDelegate(
(BuildContext context, int index) {
return Container(
margin: EdgeInsets.symmetric(
horizontal: 15,
vertical: 15,
),
alignment: Alignment.center,
color: Colors.teal[100 * (index % 9)],
child: Text('grid item $index'),
);
},
childCount: 100,
),
),
],
),
);
}
}
class _CustomShape extends ShapeBorder {
const _CustomShape({
this.side = BorderSide.none,
this.borderRadius = BorderRadius.zero,
}) : assert(side != null),
assert(borderRadius != null);
final BorderRadiusGeometry borderRadius;
/// The style of this border.
final BorderSide side;
@override
EdgeInsetsGeometry get dimensions => EdgeInsets.all(side.width);
@override
ShapeBorder scale(double t) {
return _CustomShape(
side: side.scale(t),
borderRadius: borderRadius * t,
);
}
@override
ShapeBorder lerpFrom(ShapeBorder a, double t) {
assert(t != null);
if (a is ContinuousRectangleBorder) {
return ContinuousRectangleBorder(
side: BorderSide.lerp(a.side, side, t),
borderRadius: BorderRadiusGeometry.lerp(a.borderRadius, borderRadius, t),
);
}
return super.lerpFrom(a, t);
}
@override
ShapeBorder lerpTo(ShapeBorder b, double t) {
assert(t != null);
if (b is ContinuousRectangleBorder) {
return ContinuousRectangleBorder(
side: BorderSide.lerp(side, b.side, t),
borderRadius: BorderRadiusGeometry.lerp(borderRadius, b.borderRadius, t),
);
}
return super.lerpTo(b, t);
}
@override
Path getInnerPath(Rect rect, { TextDirection textDirection }) {
double length = 16;
return Path()
..lineTo(0, rect.height - length)
..lineTo(rect.width, rect.height - length)
..lineTo(rect.width, 0)
..close();
}
@override
Path getOuterPath(rect, {TextDirection textDirection}) {
double length = 16; //its just a random number I came up with to test the border
return Path()
..lineTo(0, rect.height)
..quadraticBezierTo(length / 4, rect.height - length, length, rect.height - length)
..lineTo(rect.width - length, rect.height - length)
..quadraticBezierTo(rect.width - (length / 4), rect.height - length, rect.width, rect.height)
..lineTo(rect.width, 0)
..close();
}
@override
void paint(Canvas canvas, Rect rect, { TextDirection textDirection }) {
if (rect.isEmpty)
return;
switch (side.style) {
case BorderStyle.none:
break;
case BorderStyle.solid:
final Path path = getOuterPath(rect, textDirection: textDirection);
final Paint paint = side.toPaint();
canvas.drawPath(path, paint);
break;
}
}
@override
bool operator ==(Object other) {
if (other.runtimeType != runtimeType)
return false;
return other is ContinuousRectangleBorder
&& other.side == side
&& other.borderRadius == borderRadius;
}
@override
int get hashCode => hashValues(side, borderRadius);
}
我所做的是创建一个基于 ContinuousRectangleBorder 的自定义 ShapeBorder 但将 getOuterPath 和 getInnerPath 更改为一个常量值以使其看起来像这样（例如，如果您想要一个可以在多种情况下使用的自定义类可能会改变构造函数中的一些其他值）。
我仍然在 SliverAppBar 中使用，因为那是允许我使用 shape 属性更改形状的小部件，但是使用 getOuterPath 我绘制了从小部件的最大高度到 maxHeight - 16 的曲线（我想出了一个随机数，就像我添加时的前一个示例BorderRadius.vertical(bottom: Radius.circular(16))）。如果您没有 Sliver AppBar 而不是 Scaffold 中的 AppBar，您可以将 CustomScrollView 包装在没有边距和形状的 Card 中RoundedRectangleBorder( borderRadius: BorderRadius.vertical(top: Radius.circular(16)))以获得类似的效果
更新包
添加flutter_group_sliver: ^0.0.2到您的 pubspec.yaml 依赖项
dependencies:
flutter:
sdk: flutter
flutter_group_sliver: ^0.0.2
将其导入您的项目并在 CustomScrollView 中使用新类 SliverGroupBuilder()，它基本上是一个制成 Sliver 的容器，因此您可以在 Sliver 中使用边距、装饰、填充选项
import 'package:flutter_group_sliver/flutter_group_sliver.dart';
Scaffold(
backgroundColor: Colors.pink[100],
body: CustomScrollView(
slivers: <Widget>[
SliverAppBar(
pinned: true,
floating: true,
expandedHeight: 250.0,
elevation: 0.0,
forceElevated: false,
flexibleSpace: FlexibleSpaceBar(
background: Image.network(
"https://happypixelmedia.com/wp-content/uploads/2019/10/Web-design-ideas-to-look-forward-to-in-2020-cover-1.jpg",
fit: BoxFit.cover,
),
title: Text('Hello there'),
),
),
SliverGroupBuilder(
margin: EdgeInsets.zero,
decoration: BoxDecoration(
color: Colors.orange,
borderRadius: BorderRadius.vertical(top: Radius.circular(16)),
),
child: SliverGrid(
gridDelegate: SliverGridDelegateWithMaxCrossAxisExtent(
maxCrossAxisExtent: 200.0,
mainAxisSpacing: 10.0,
crossAxisSpacing: 10.0,
childAspectRatio: 4.0,
),
delegate: SliverChildBuilderDelegate(
(BuildContext context, int index) {
return Container(
margin: EdgeInsets.symmetric(
horizontal: 15,
vertical: 15,
),
alignment: Alignment.center,
color: Colors.teal[100 * (index % 9)],
child: Text('grid item $index'),
);
},
childCount: 100,
),
),
)
],
),
)
Scaffold 背景为粉红色，SliverGroupBuilder 为橙色，带有BorderRadius.vertical(top: Radius.circular(16)),
关闭的 SliverAppBar
这种方法可以满足您的需求，但您必须注意脚手架背景的颜色以使其不同，以便您可以看到边界半径
检查https://pub.dev/packages/flutter_group_sliver#-readme-tab-以获取该软件包的更多信息
