flutter ScrollController attached to multiple scroll views

Instead of using a static controller, you should have one controller per widget instance.

You cannot store your controller inside a StatelessWidget though (even if the compiler will allow it).

You need a StatefulWidget for that, or else when your widget is updated you will create a new controller again. Leading to weird behaviors.

Here the final code:

class NumScroller extends StatefulWidget{
  final int max,min;
  final double height,width;
  final TextAlign alignment;

  NumScroller({this.height,this.width,this.alignment,this.min,this.max, initialOffset});

  @override
  NumScrollerState createState() {
    return new NumScrollerState();
  }
}

class NumScrollerState extends State<NumScroller> {
  final ScrollController controller = ScrollController();

  getValue() => (controller.offset~/widget.height) + widget.min;

  @override
  Widget build(BuildContext context) {
    return new Container(
        width: widget.width,
        height: widget.height,
        child: ListView.builder(itemBuilder: (context, index) {
          return new Container(height: widget.height, child:Text((widget.max - index).toString(),textAlign: widget.alignment,));
          },
          itemCount: widget.max - widget.min+1,
          controller: controller,
          physics: PageScrollPhysics(),
          itemExtent: widget.height,
        )
    );
  }
}

As you are telling when multiple instances are rendered, you are getting this error. When your ScrollController is multiple(one for one view), you will not get any problem. But you have only one ScrollController (because you have static).

Remove the static and it should work.

Please lemme know if it didn't work.