Sliding overflow: slides a long widget (like a text)

sliding_overflow.dart

import 'dart:math';

import 'package:flutter/material.dart';

class SlidingOverflow extends StatefulWidget {
  final Widget child;

  const SlidingOverflow({Key key, this.child}) : super(key: key);
  @override
  _SlidingOverflowState createState() => _SlidingOverflowState();
}

class _SlidingOverflowState extends State<SlidingOverflow> {
  final kOffsetIncrement = 10.0;
  final kDuration = Duration(milliseconds: 500);
  final controller = ScrollController();
  var started = false;

  @override
  void dispose() {
    controller?.dispose();
    super.dispose();
  }

  void controllerLoop() async {
    final destination = min(controller.position.maxScrollExtent,
        controller.offset + kOffsetIncrement);

    await controller.animateTo(
      destination,
      duration: kDuration,
      curve: Curves.linear,
    );
    controllerLoop();
  }

  @override
  Widget build(BuildContext context) {
    if (!started) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        started = true;
        controllerLoop();
      });
    }
    return ListView.builder(
      scrollDirection: Axis.horizontal,
      controller: controller,
      itemBuilder: (_, __) => widget.child,
    );
  }
}