Flutter -如何在单击时切换FlatButton的颜色？

import 'package:flutter/material.dart';

class MyFlatButton extends StatefulWidget {
  @override
  _MyFlatButtonState createState() => _MyFlatButtonState();
}

class _MyFlatButtonState extends State<MyFlatButton> {
  Color _buttonColor = Colors.blue; // 初始颜色为蓝色

  void _changeColor() {
    setState(() {
      // 在点击时切换颜色
      _buttonColor = _buttonColor == Colors.blue ? Colors.red : Colors.blue;
    });
  }

  @override
  Widget build(BuildContext context) {
    return FlatButton(
      onPressed: _changeColor,
      color: _buttonColor,
      child: Text('FlatButton'),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: Scaffold(
      appBar: AppBar(
        title: Text('Flutter FlatButton'),
      ),
      body: Center(
        child: MyFlatButton(),
      ),
    ),
  ));
}