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rusty
Asked: 2025-02-14 09:56:22 +0800 CST

在 Cupertino 日期选择器年份轮上滑动超出最小或最大日期时发生异常

  • 772

每当我“长按” Cupertino 日期选择器的年份轮（在我的 Android 应用程序中）时，以致最小年份或最大年份与年份轮交叉时，就会出现异常并显示以下消息：

Exception has occurred.
_AssertionError ('package:flutter/src/cupertino/date_picker.dart': Failed assertion: line 327 pos 10: '(mode != CupertinoDatePickerMode.date && mode != CupertinoDatePickerMode.monthYear) ||
             (minimumYear >= 1 && (initialDateTime ?? DateTime.now()).year >= minimumYear)': initial year is not greater than minimum year, or minimum year is not positive)

我已经正确设置了initialDateTimetoDateTime.now()和minimumYearto2000以及maximumYearto 2050。尽管如此，异常仍然出现，但我不知道原因。在年轮如此频繁地切换期间，我该如何解决此异常？

完整代码：

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

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

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(home: const MyHomePage());
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  DateTime _dateTime = DateTime.now();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).primaryColor,
        title: const Text("Inbuild Cupertino Date Picker Example"),
      ),
      body: Column(
        children: [
          Flexible(
            child: CupertinoDatePicker(
              initialDateTime: _dateTime,
              dateOrder: DatePickerDateOrder.ymd,
              mode: CupertinoDatePickerMode.date,
              minimumYear: 2000,
              maximumYear: 2050,
              onDateTimeChanged: (newDateTime) {
                print("############## DateTime: ${newDateTime}");
                setState(() {
                  _dateTime = newDateTime;
                });
              },
            ),
          ),
        ],
      ),
      bottomNavigationBar: Container(
        padding: EdgeInsets.all(15.0),
        height: 60.0,
        width: double.infinity,
        decoration: BoxDecoration(color: Colors.amberAccent),
        child: const Text("Bottom Navigation Bar"),
      ),
    );
  }
}
flutter

1 个回答

  1. Best Answer

    您不需要每次 setState 时都更新 initialDateTime。为选定的日期引入一个新变量。最初，当您更改为另一个日期时，它们两个将是相同的：

    _dateTime <-- DateTime.now()
_selectedDateTime <-- Next Selected date in CupertinoDatePicker

    以下是您的代码所需的更改：

    最终 DateTime _dateTime = DateTime.now();
    DateTime _selectedDateTime = DateTime.now();

          Flexible(
        child: CupertinoDatePicker(
          initialDateTime: _dateTime,
          dateOrder: DatePickerDateOrder.ymd,
          mode: CupertinoDatePickerMode.date,
          minimumYear: 2000,
          maximumYear: 2050,
          onDateTimeChanged: (newDateTime) {
            print("############## DateTime: ${newDateTime}");
            setState(() {
              //CHANGED THIS VARIABLE
              _selectedDateTime = newDateTime;
            });
          },
        ),

    我在我的设备上测试过，没有异常。如果你这边的问题仍然存在，请提及你的 Flutter 和 Dart 版本

    • 1

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