我创建了一个新的flutter项目,并添加了sticky_headers程序包。
然后,我实现了一个具有ScrollController的列表生成器。 我每隔5秒调用一次setState 3次,并修改一个全局偏移量变量,该变量将在build方法上使用,以将列表跳转到一个新的偏移量(使用SchedulerBinding.instance.addPostFrameCallback)。
问题在于,在我调用jumpto方法之后,标题被弄乱了(如果我手动滚动,标题将返回到正常位置)。
示例:
代码:
import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';
import 'package:sticky_headers/sticky_headers.dart';
double offset = 0;
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key}) : super(key: key);
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
ScrollController _scrollController = ScrollController();
@override
void initState() {
super.initState();
Future.delayed(Duration(seconds: 5)).then((_) => setState(() {
offset = 3000;
})).then((_) async => await Future.delayed(Duration(seconds: 5))).then((_) => setState(() {
offset = 1000;
})).then((_) async => await Future.delayed(Duration(seconds: 5))).then((_) => setState(() {
offset = 5000;
}));
}
@override
Widget build(BuildContext context) {
SchedulerBinding.instance.addPostFrameCallback((_) {
print(offset);
_scrollController.jumpTo(offset);
});
return Scaffold(body: Container(padding: EdgeInsets.only(top: 20),child: _buildList(context)));
}
Widget _buildList(BuildContext context) {
return NotificationListener<ScrollNotification>(
child: ListView.builder(
controller: _scrollController,
itemCount: 100,
itemBuilder: (BuildContext context, int sectionIndex) => StickyHeader(
header: Container(
height: 50,
alignment: Alignment.center,
color: Colors.blue,
child: Text("$sectionIndex")),
content: ListView.builder(
itemCount: 10,
shrinkWrap: true,
physics: NeverScrollableScrollPhysics(),
itemBuilder: (context, rowIndex) => Container(
color: Colors.white,
child: Text("$sectionIndex"))))),
onNotification: (ScrollNotification scrollNotification) {
offset = _scrollController.offset;
print(offset);
return true;
});
}
}