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Description:

linked scroll controller

linked_scroll_controller #
This package provides a way to set up a set of scrollable widgets whose
scrolling is synchronized. The set can be stable across the lifetime of the
containing screen, or can change dynamically (for example, a vertically
scrolling ListView.builder() whose items are Scrollables that scroll
horizontally in unison).
If you add controllers dynamically, the corresponding scrollables must be
given unique keys to avoid the scroll offset going out of sync.
Example usage #
The code below sets up two side-by-side ListViews that scroll in unison.
class LinkedScrollables extends StatefulWidget {
@override
_LinkedScrollablesState createState() => _LinkedScrollablesState();
}

class _LinkedScrollablesState extends State<LinkedScrollables> {
LinkedScrollControllerGroup _controllers;
ScrollController _letters;
ScrollController _numbers;

@override
void initState() {
super.initState();
_controllers = LinkedScrollControllerGroup();
_letters = _controllers.addAndGet();
_numbers = _controllers.addAndGet();
}

@override
void dispose() {
_letters.dispose();
_numbers.dispose();
super.dispose();
}

@override
Widget build(BuildContext context) {
return Directionality(
textDirection: TextDirection.ltr,
child: Row(
children: [
Expanded(
child: ListView(
controller: _letters,
children: <Widget>[
_Tile('Hello A'),
_Tile('Hello B'),
_Tile('Hello C'),
_Tile('Hello D'),
_Tile('Hello E'),
],
),
),
Expanded(
child: ListView(
controller: _numbers,
children: <Widget>[
_Tile('Hello 1'),
_Tile('Hello 2'),
_Tile('Hello 3'),
_Tile('Hello 4'),
_Tile('Hello 5'),
],
),
),
],
),
);
}
}

class _Tile extends StatelessWidget {
final String caption;

_Tile(this.caption);

@override
Widget build(_) => Container(
margin: const EdgeInsets.all(8.0),
padding: const EdgeInsets.all(8.0),
height: 250.0,
child: Center(child: Text(caption)),
);
}

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