import 'dart:async';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Scaffold(
appBar: AppBar(
title: const Text('倒计时'),
),
body: const MyHomePage(),
));
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key}) : super(key: key);
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
late Duration time;
var seconds = 0;
Timer? countdownTimer;
@override
Widget build(BuildContext context) {
return Center(
child: Column(
children: <Widget>[
ElevatedButton(
child: const Text('定时'),
onPressed: () {
showCupertinoModalPopup<void>(
context: context,
builder: (BuildContext context) {
return Container(
height: 200,
color: CupertinoColors.white,
child: DefaultTextStyle(
style: const TextStyle(
color: CupertinoColors.black,
fontSize: 22.0,
),
child: CupertinoTimerPicker(
//initialTimerDuration: time,
//minuteInterval: 5,
mode: CupertinoTimerPickerMode.ms,
onTimerDurationChanged: (Duration newTimer) {
setState(() {
time = newTimer;
seconds = time.inSeconds;
// flag = true;
});
},
),
));
},
);
},
),
ElevatedButton(
child: const Text('开始倒计时'),
onPressed: () {
if (countdownTimer != null) {
return;
}
countdownTimer =
Timer.periodic(const Duration(seconds: 1), (timer) {
setState(() {
if (seconds > 0) {
seconds--;
} else {
countdownTimer?.cancel();
countdownTimer = null;
}
});
});
},
),
Text(
'倒计时： $seconds 秒',
style: const TextStyle(fontSize: 30),
),
],
),
);
}
@override
void dispose() {
countdownTimer?.cancel();
countdownTimer = null;
super.dispose();
}
}
参考链接