我已将 ScrollController 附加到 [SliverAppBar, SliverList] 的 CustomScrollView
在默认情况下,我会使用 reverse:true 和 animateTo (0.0) 将滚动移动到添加的最后一个元素,但在这种情况下,使用 reverse 也会反转 SliverAppBar/SliverList 的顺序!
所以我想使用 animateTo ( sizeOfScrollableAfterElementAdded ) 但我找不到这个值。
谢谢!
最佳答案
您可以使用 _scrollController.position.maxScrollExtent
滚动到最后。确保在帧后回调中执行此操作,以便它包含您刚刚添加的新项目。
这是一个随着更多项目的添加而滚动到末尾的条形列表示例。
import 'package:flutter/scheduler.dart';
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Flutter Demo',
home: new MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
State createState() => new MyHomePageState();
}
class MyHomePageState extends State<MyHomePage> {
ScrollController _scrollController = new ScrollController();
List<Widget> _items = new List.generate(40, (index) {
return new Text("item $index");
});
@override
Widget build(BuildContext context) {
return new Scaffold(
floatingActionButton: new FloatingActionButton(
child: new Icon(Icons.arrow_downward),
onPressed: () {
setState(() {
_items.add(new Text("item ${_items.length}"));
});
SchedulerBinding.instance.addPostFrameCallback((_) {
_scrollController.animateTo(
_scrollController.position.maxScrollExtent,
duration: const Duration(milliseconds: 300),
curve: Curves.easeOut,
);
});
},
),
body: new CustomScrollView(
controller: _scrollController,
slivers: [
new SliverAppBar(
title: new Text('Sliver App Bar'),
),
new SliverList(
delegate: new SliverChildBuilderDelegate(
(context, index) => _items[index],
childCount: _items.length,
),
),
],
),
);
}
}
https://stackoverflow.com/questions/44141148/