一旦视图更改，颤动数字时钟小部件就会导致错误
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【中文标题】一旦视图更改，颤动数字时钟小部件就会导致错误【英文标题】：Flutter digital clock widget causing errors as soon as the view is changed 【发布时间】：2021-05-24 08:42:04 【问题描述】：我正在使用https://pub.dev/packages/slide_digital_clock，它会导致内存泄漏和动画错误垃圾邮件，我不知道如何修复它，一旦视图被发送回注销，就会发生这种情况。如果有人能解释一下如何修复它，将不胜感激
import 'dart:convert';
import 'package:flutter/widgets.dart';
import 'package:attenv02/login_page.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
import 'package:geolocator/geolocator.dart';
import 'package:slide_digital_clock/slide_digital_clock.dart';
import 'package:intl/intl.dart';
class HomePage extends StatefulWidget
@override
_HomePageState createState() => _HomePageState();
class _HomePageState extends State<HomePage>
var locationMessege= "";
bool timeinbtn = true;
bool timeoutbtn = false;
String name = "";
void initState()
super.initState();
Future <String> loadPref()async
SharedPreferences sharedPreferences = await SharedPreferences.getInstance();
return Future.delayed(Duration(seconds: 1),()async
return await sharedPreferences.getString("useFullName");
);
logout()async
SharedPreferences sharedPreferences = await SharedPreferences.getInstance();
sharedPreferences.clear();
sharedPreferences.commit();
Navigator.of(context).pushAndRemoveUntil(MaterialPageRoute(builder: (BuildContext context)
=> LoginPage()), (Route<dynamic> route) => false);
void getCurrentLocation()async
var position = await Geolocator.getCurrentPosition(desiredAccuracy: LocationAccuracy.high);
var lastPosition=await Geolocator.getLastKnownPosition();
String now =await new DateFormat.yMd().add_Hm().format(new DateTime.now());
timeinbtn=!timeinbtn;
timeoutbtn=!timeoutbtn;
print(lastPosition);
print(now);
setState(()
locationMessege="$position.latitude,$position.longitude,$now";
);
@override
Widget build(BuildContext context)
return Scaffold(
appBar: AppBar(
backgroundColor:Color.fromRGBO(255, 191, 68, 1),
title:FutureBuilder(
future: loadPref(),
builder: (context, snapshot)
if(snapshot.hasData)
return Text("$snapshot.data");
else
return Text("Loading");
,
),
actions: <Widget>[
FlatButton(
onPressed: ()
logout();
,
child: Text("Log Out", style: TextStyle(color: Colors.white)),
),
],
),
body: Container(
decoration: BoxDecoration(
image: DecorationImage(
image: AssetImage("assets/bg.jpg"), fit: BoxFit.cover)),
child: Center(
child: Container(
padding: EdgeInsets.all(30),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Column(
children:<Widget> [
Container(
child:DigitalClock(
digitAnimationStyle: Curves.elasticOut,
is24HourTimeFormat: false,
areaDecoration: BoxDecoration(
color: Colors.transparent,
),
hourMinuteDigitTextStyle: TextStyle(
color: Colors.blueGrey,
fontSize: 50,
),
amPmDigitTextStyle: TextStyle(color: Colors.blueGrey, fontWeight: FontWeight.bold),
),
),
Text("Position:$locationMessege",style:TextStyle(
color: Colors.black,
fontSize: 10.0,
fontWeight: FontWeight.bold)),
Visibility(
visible:timeinbtn,
child: FlatButton(onPressed:()
getCurrentLocation();
,
color: Colors.orange,
child: Text("Time in",
style: TextStyle(
color: Colors.white,
),)),
),
Visibility(
visible: timeoutbtn,
child: FlatButton(onPressed:()
getCurrentLocation();
,
color: Colors.orange,
child: Text("Time out",
style: TextStyle(
color: Colors.white,
),)),
)
],
),
],
),
),
),
),
);
在最终确定小部件树时引发了以下断言： _SpinnerTextState#321b2(ticker active) 与活动的 Ticker 一起处置。
_SpinnerTextState 通过其 SingleTickerProviderStateMixin 创建了一个 Ticker，但在 mixin 上调用 dispose() 时，该 Ticker 仍然处于活动状态。 Ticker 必须在调用 super.dispose() 之前被释放。
AnimationControllers 使用的代码应该通过调用 AnimationController 本身的 dispose() 来处理。否则，代码会泄露。
动画库捕获的异常 在通知 AnimationController 的侦听器时引发了以下断言： 'package:flutter/src/widgets/framework.dart'：断言失败：第 4109 行 pos 12：'_lifecycleState != _ElementLifecycle.defunct'：不正确。
动画库捕获的异常 'package:flutter/src/widgets/framework.dart'：断言失败：第 4109 行 pos 12：'_lifecycleState != _ElementLifecycle.defunct'：不正确。
动画库捕获的异常 'package:flutter/src/widgets/framework.dart'：断言失败：第 4109 行 pos 12：'_lifecycleState != _ElementLifecycle.defunct'：不正确。
【问题讨论】：
【参考方案1】：这个包有两个错误，有两个拉取请求来修复这些问题，但是你必须手动合并它们，因为这两个拉取请求没有被所有者合并
第一步：更新lib/helpers/spinner_text.darthttps://github.com/caglarylmz/slide_digital_clock/pull/4/files/23cd40ac4f32fc7adeab4101af498994d40d43fd
从改变
@override
void dispose()
super.dispose();
_spinTextAnimationController.dispose();
到
@override
void dispose()
_spinTextAnimationController.dispose();
super.dispose();
第二步：取消定时器，更新类_DigitalClockStatehttps://github.com/caglarylmz/slide_digital_clock/pull/1/commits/5a648954e83e8215180e05db5bbf9e232e4d385a
代码sn-p
Timer _timer;
...
_timer = Timer.periodic(Duration(seconds: 1), (timer)
...
@override
void dispose()
_timer.cancel();
super.dispose();
手动合并这两个拉取请求后的工作演示
工作演示的完整代码
import 'package:flutter/material.dart';
import 'package:slide_digital_clock/slide_digital_clock.dart';
void main()
runApp(MyApp());
class MyApp extends StatelessWidget
@override
Widget build(BuildContext context)
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: HomePage(),
);
class HomePage extends StatefulWidget
@override
_HomePageState createState() => _HomePageState();
class _HomePageState extends State<HomePage>
var locationMessege = "";
bool timeinbtn = true;
bool timeoutbtn = false;
String name = "";
void initState()
super.initState();
Future<String> loadPref() async
/*SharedPreferences sharedPreferences = await SharedPreferences.getInstance();
return Future.delayed(Duration(seconds: 1), () async
return await sharedPreferences.getString("useFullName");
);*/
return Future.value("useFullName");
logout() async
Navigator.of(context).pushAndRemoveUntil(
MaterialPageRoute(builder: (BuildContext context) => LoginPage()),
(Route<dynamic> route) => false);
void getCurrentLocation() async
/*var position = await Geolocator.getCurrentPosition(
desiredAccuracy: LocationAccuracy.high);
var lastPosition = await Geolocator.getLastKnownPosition();
String now = await new DateFormat.yMd().add_Hm().format(new DateTime.now());
timeinbtn = !timeinbtn;
timeoutbtn = !timeoutbtn;
print(lastPosition);
print(now);
setState(()
locationMessege = "$position.latitude,$position.longitude,$now";
);*/
@override
Widget build(BuildContext context)
return Scaffold(
appBar: AppBar(
backgroundColor: Color.fromRGBO(255, 191, 68, 1),
title: FutureBuilder(
future: loadPref(),
builder: (context, snapshot)
if (snapshot.hasData)
return Text("$snapshot.data");
else
return Text("Loading");
,
),
actions: <Widget>[
FlatButton(
onPressed: ()
logout();
,
child: Text("Log Out", style: TextStyle(color: Colors.white)),
),
],
),
body: Container(
/*decoration: BoxDecoration(
image: DecorationImage(
image: NetworkImage("https://picsum.photos/250?image=9"),
fit: BoxFit.cover)),*/
child: Center(
child: Container(
padding: EdgeInsets.all(30),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Column(
children: <Widget>[
Container(
child: DigitalClock(
digitAnimationStyle: Curves.elasticOut,
is24HourTimeFormat: false,
areaDecoration: BoxDecoration(
color: Colors.transparent,
),
hourMinuteDigitTextStyle: TextStyle(
color: Colors.blueGrey,
fontSize: 50,
),
amPmDigitTextStyle: TextStyle(
color: Colors.blueGrey,
fontWeight: FontWeight.bold),
),
),
Text("Position:$locationMessege",
style: TextStyle(
color: Colors.black,
fontSize: 10.0,
fontWeight: FontWeight.bold)),
Visibility(
visible: timeinbtn,
child: FlatButton(
onPressed: ()
getCurrentLocation();
,
color: Colors.orange,
child: Text(
"Time in",
style: TextStyle(
color: Colors.white,
),
)),
),
Visibility(
visible: timeoutbtn,
child: FlatButton(
onPressed: ()
getCurrentLocation();
,
color: Colors.orange,
child: Text(
"Time out",
style: TextStyle(
color: Colors.white,
),
)),
)
],
),
],
),
),
),
),
);
class LoginPage extends StatelessWidget
@override
Widget build(BuildContext context)
return Scaffold(body: Center(child: Text("Login Page")));
【讨论】：
如果这是一个愚蠢的问题，请道歉，但我是否需要创建文件或查找包文件，我的 lib 文件夹中没有 lib/helpers/spinner_text.dart 文件包含的主库我的应用飞镖 您可以将github中的所有代码复制粘贴到您的项目中，然后进行修改。或者直接 fork 这个 github 项目。 很高兴为您提供帮助。如果对您有帮助，请将其标记为答案。谢谢。 我在哪里复制它，我需要创建一个新的飞镖作为 lib/helpers/spinner_text.dart 吗？我在哪里可以找到这个 spinner_text.dart ？ 是的。您可以复制所有文件并按照所有者的目录github.com/caglarylmz/slide_digital_clock/tree/master/lib 到您的项目中以上是关于一旦视图更改，颤动数字时钟小部件就会导致错误的主要内容，如果未能解决你的问题，请参考以下文章