如何在flluter中创建一个在屏幕前显示的数字选择器旋转器？

在Flutter中创建一个在屏幕前显示的数字选择器旋转器可以通过使用Flutter的内置组件和动画来实现。以下是一个基本的实现步骤：

导入所需的Flutter包：

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

创建一个StatefulWidget类来管理数字选择器的状态：

class NumberSelector extends StatefulWidget {
  @override
  _NumberSelectorState createState() => _NumberSelectorState();
}

class _NumberSelectorState extends State<NumberSelector> {
  int selectedNumber = 0;

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Text(
            'Selected Number: $selectedNumber',
            style: TextStyle(fontSize: 20),
          ),
          SizedBox(height: 20),
          CupertinoPicker(
            itemExtent: 50,
            onSelectedItemChanged: (index) {
              setState(() {
                selectedNumber = index;
              });
            },
            children: List<Widget>.generate(10, (index) {
              return Center(
                child: Text(
                  '$index',
                  style: TextStyle(fontSize: 30),
                ),
              );
            }),
          ),
        ],
      ),
    );
  }
}

在主界面中使用NumberSelector组件：

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Number Selector'),
        ),
        body: Center(
          child: NumberSelector(),
        ),
      ),
    );
  }
}