Flutter 中的 CupertinoTimePicker 小部件：全面指南

在Flutter中，CupertinoTimePicker是一个用于选择时间的小部件，它专为iOS风格应用设计。以下是如何使用CupertinoTimePicker的示例代码：

import 'package:flutter/cupertino.dart';
 
class TimePickerExample extends StatefulWidget {
  @override
  _TimePickerExampleState createState() => _TimePickerExampleState();
}
 
class _TimePickerExampleState extends State<TimePickerExample> {
  TimeOfDay _selectedTime = TimeOfDay.now();
 
  void _selectTime(BuildContext context) async {
    final TimeOfDay? picked = await showCupertinoModalPopup<TimeOfDay>(
      context: context,
      builder: (BuildContext context) {
        return CupertinoTimePicker(
          initialTime: _selectedTime,
          onChanged: (TimeOfDay newTime) {
            setState(() {
              _selectedTime = newTime;
            });
          },
        );
      },
    );
 
    if (picked != null && picked != _selectedTime) {
      setState(() {
        _selectedTime = picked;
      });
    }
  }
 
  @override
  Widget build(BuildContext context) {
    return CupertinoApp(
      home: CupertinoPageScaffold(
        navigationBar: CupertinoNavigationBar(
          trailing: CupertinoButton(
            child: Text('选择时间'),
            onPressed: () => _selectTime(context),
          ),
        ),
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text('选择的时间: $_selectedTime'),
            ],
          ),
        ),
      ),
    );
  }
}

这段代码创建了一个CupertinoTimePicker，并通过showCupertinoModalPopup在弹出窗口中显示。用户可以通过滑动选择时间，选择的时间将通过回调函数更新到_selectedTime变量中。这个例子展示了如何在Flutter应用中整合CupertinoTimePicker，并且如何处理用户的选择。