Flutter QR Code 生成器 - 50 秒自动更新

import 'dart:async';

import 'package:dio/dio.dart'; import 'package:flutter/material.dart'; import 'package:muse_nepu_course/global.dart'; import 'package:pretty_qr_code/pretty_qr_code.dart';

class QRCode extends StatefulWidget { @override _QRCodeState createState() => _QRCodeState(); }

class _QRCodeState extends State { void initState() { super.initState(); _countdownTimer(); }

String endtime = '还有55s'; int _countdownTime = 50; //定时器50s,每50s刷新一次二维码，每1s刷新一次endtime void _countdownTimer() { const oneSec = const Duration(seconds: 1); var callback = (timer) => { setState(() { if (_countdownTime < 1) { //刷新二维码并重置endtime Global().getqr(); _countdownTime = 50; setState(() {}); } else { print(_countdownTime); _countdownTime = _countdownTime - 1; endtime = '还有$_countdownTime s' + Global.qrcode; setState(() {}); } }) }; Timer.periodic(oneSec, callback); }

//获取endtime String getendtime() { return endtime; }

String passtemp = "";

@override Widget build(BuildContext context) { return MaterialApp( home: Scaffold( appBar: AppBar( title: Text('一卡通二维码'), //设置 actions: [ IconButton( icon: Icon(Icons.settings), onPressed: () { //弹窗一个文本框加上一个确认框 showDialog( context: context, builder: (context) { return AlertDialog( title: Text('修改你的一卡通密码\n如果没有错误请不要修改'), content: TextField( onChanged: (value) { passtemp = value; }, ), actions: [ TextButton( child: Text('确认'), onPressed: () { Global.password = passtemp; Global.saveaccount(); Navigator.of(context).pop(); }, ) ], ); }); }, ), ], ), body: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ Align( alignment: Alignment.topCenter, child: Text( getendtime(), style: TextStyle(fontSize: 20), ), ), Expanded( child: GestureDetector( onTap: () { Global().getqr(); _countdownTime = 50; setState(() {}); }, child: PrettyQr( typeNumber: 3, size: 200, data: Global.qrcodegetter(), errorCorrectLevel: QrErrorCorrectLevel.M, roundEdges: true, ), ), ), ], ), )); } }