我记得，我也遇到了同样的挑战。

我创建了自己的wave滑块：

import 'dart:math';

import 'package:flutter/material.dart';

List<int> bars = [];
const barWidth = 5.0;
double screenWidth;
int numberOfBars;

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Home(),
    );
  }
}

void randomNumberGenerator() {
  Random r = Random();
  for (var i = 0; i < numberOfBars; i++) {
    bars.add(r.nextInt(40) + 10);
  }
}

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    if (bars.isEmpty) {
      screenWidth = MediaQuery.of(context).size.width;
      numberOfBars = screenWidth ~/ barWidth;
      randomNumberGenerator();
    }
    return Container(child: WaveSlider());
  }
}

class WaveSlider extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => WaveSliderState();
}

class WaveSliderState extends State<WaveSlider> {
  double bar2Position = 180.0;

  _onTapDown(TapDownDetails details) {
    var x = details.globalPosition.dx;
    print("tap down " + x.toString());
    setState(() {
      bar2Position = x;
    });
  }

  @override
  Widget build(BuildContext context) {
    int barItem = 0;
    return Scaffold(
      body: Center(
        child: Stack(
          alignment: Alignment.centerLeft,
          children: <Widget>[
            GestureDetector(
              onTapDown: (TapDownDetails details) => _onTapDown(details),
              onHorizontalDragUpdate: (DragUpdateDetails details) {
                setState(() {
                  bar2Position = details.globalPosition.dx;
                });
              },
              child: Container(
                child: Row(
                  crossAxisAlignment: CrossAxisAlignment.end,
                  mainAxisAlignment: MainAxisAlignment.start,
                  children: bars.map((int height) {
                    Color color = barItem + 1 < bar2Position / barWidth
                        ? Colors.deepPurple
                        : Colors.blueGrey;
                    barItem++;
                    return Container(
                      color: color,
                      height: height.toDouble(),
                      width: 5.0,
                    );
                  }).toList(),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}