flutter - 为什么颤动的“返回顶部按钮”不起作用

Question

我正在我的 Flutter 应用程序上创建一个返回顶部按钮，但它不起作用。这是按钮的 Dart 文件：

import 'package:flutter/material.dart';
import 'package:flutter_app/Widgets/GlobalWidgets/SelectionButton.dart';

class ToTheTopButton extends StatefulWidget {
  @override
  _ToTheTopButtonState createState() => _ToTheTopButtonState();
}

class _ToTheTopButtonState extends State<ToTheTopButton> with TickerProviderStateMixin {

  ScrollController _scrollController = ScrollController();
/*
  @override
  void dispose() {
    _scrollController.dispose(); // dispose the controller
    super.dispose();
  }*/

  // This function is triggered when the user presses the back-to-top button
  void _scrollToTop() {
    _scrollController.animateTo(0,
        duration: Duration(seconds: 3), curve: Curves.linear);
  }


  @override
  Widget build(BuildContext context) {
    return SelectionButton(name: "To the top", onTap: _scrollToTop);
  }
}

我在底部导航栏中实现了这个按钮，而底部导航栏在我的主页中实现。“SelectionButton”的代码如下：

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

class SelectionButton extends StatelessWidget {

  SelectionButton({required this.name, required this.onTap});

  String name;
  void Function() onTap;

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Padding(
        padding: const EdgeInsets.all(8.0),
        child: TextButton(onPressed: onTap, child: Text(name, style: TextStyle(color: Colors.black)),),
      ),

    );
  }
}