在 flutter 上显示运行时钟

Question

我想知道是否有办法在 dart 中显示实时时钟？ 日期和时间（例如 11/14/2018 19:34）并且时间将继续运行。

可以从设备本身获取时间。

Answer 1

最简单的解决方案：

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

class ClockWidget extends StatelessWidget {
  const ClockWidget({super.key});

  @override
  Widget build(BuildContext context) {
    return StreamBuilder(
      stream: Stream.periodic(const Duration(seconds: 1)),
      builder: (context, snapshot) {
        return Text(DateFormat('MM/dd/yyyy hh:mm:ss').format(DateTime.now()));
      },
    );
  }
}

把它放在你喜欢的任何地方。

编辑：如果在案例参数化中无法使用

const

构造函数，则更可靠的实现是：

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

  @override
  State<ClockWidget> createState() => _ClockWidgetState();
}

class _ClockWidgetState extends State<ClockWidget>
    with SingleTickerProviderStateMixin {
  late final tickerProvider = createTicker((elapsed) => setState(() {}));

  @override
  void initState() {
    tickerProvider.start();
    super.initState();
  }

  @override
  void dispose() {
    tickerProvider.stop();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Text(DateFormat('MM/dd/yyyy hh:mm:ss').format(DateTime.now()));
  }
}

Answer 2

下面使用

intl

插件将时间格式化为

MM/dd/yyyy hh:mm:ss

。请务必更新您的

pubspec.yaml

。

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Time Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Time Demo'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String _timeString;

  @override
  void initState() {
    _timeString = _formatDateTime(DateTime.now());
    Timer.periodic(Duration(seconds: 1), (Timer t) => _getTime());
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Text(_timeString),
      ),
    );
  }

  void _getTime() {
    final DateTime now = DateTime.now();
    final String formattedDateTime = _formatDateTime(now);
    setState(() {
      _timeString = formattedDateTime;
    });
  }

  String _formatDateTime(DateTime dateTime) {
    return DateFormat('MM/dd/yyyy hh:mm:ss').format(dateTime);
  }
}

Answer 3

这与 Albert 给出的代码相同，但如果您不想使用 intl 包，您可以对此代码进行以下更改：

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

void main () => runApp(MyApp());

class MyApp extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(primarySwatch: Colors.red),
      home: FlutterTimeDemo(),
    );
  }
}

class FlutterTimeDemo extends StatefulWidget{
  @override
  _FlutterTimeDemoState createState()=> _FlutterTimeDemoState();

}

class _FlutterTimeDemoState extends State<FlutterTimeDemo>
{
  String _timeString;

  @override
  void initState(){
    _timeString = "${DateTime.now().hour} : ${DateTime.now().minute} :${DateTime.now().second}";
    Timer.periodic(Duration(seconds:1), (Timer t)=>_getCurrentTime());
    super.initState();
  }

 @override
 Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Fluter Test'),),
      body:Center(
        child: Text(_timeString, style: TextStyle(fontSize: 30),),
      ),
    );
  }

  void _getCurrentTime()  {
    setState(() {
  _timeString = "${DateTime.now().hour} : ${DateTime.now().minute} :${DateTime.now().second}";
    });
  }
}