2023年9月1日星期五

Flutter: How to scroll to a specific position in ListView?

 Use Dependency:

dependencies:
scroll_to_index: ^1.0.6

Example: Generate the list of 20 items and scroll to the sixth position of Listview on click of Fab Button

Code Snippet:

import 'package:flutter/material.dart';
import 'package:scroll_to_index/scroll_to_index.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Scroll To Index Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Scroll To Index Demo'),
);
}
}

class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);

final String title;

@override
_MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
final scrollDirection = Axis.vertical;

AutoScrollController controller;
List<List<int>> randomList;

@override
void initState() {
super.initState();
controller = AutoScrollController(
viewportBoundaryGetter: () =>
Rect.fromLTRB(0, 0, 0, MediaQuery.of(context).padding.bottom),
axis: scrollDirection);
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: ListView(
scrollDirection: scrollDirection,
controller: controller,
children: <Widget>[
...List.generate(20, (index) {
return AutoScrollTag(
key: ValueKey(index),
controller: controller,
index: index,
child: Container(
height: 100,
color: Colors.red,
margin: EdgeInsets.all(10),
child: Center(child: Text('index: $index')),
),
highlightColor: Colors.black.withOpacity(0.1),
);
}),
],
),
floatingActionButton: FloatingActionButton(
onPressed: _scrollToIndex,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}

Future _scrollToIndex() async {
await controller.scrollToIndex(6, preferPosition: AutoScrollPosition.begin);
}
}

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