Flutter:我得到一个错误，一个小部件的State对象不再出现在小部件树中

Question

• 当我尝试按下发送按钮进行http请求时[成功完成]，我得到了以下错误，我该如何解决

[错误：flutter/lib/ui/ui_start_state.cc(157(]未处理的异常：在dispose((之后调用setState((：_ForgetPasswordDialogState#95548(生命周期状态：已失效，未装入

import 'dart:io';
import 'package:Zabatnee/common_app/provider/user_details_provider.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
class ForgetPasswordDialog extends StatefulWidget {
static const routeName = '/customeDialog';
final String title,description;

ForgetPasswordDialog({
this.title, 
this.description,});
@override
_ForgetPasswordDialogState createState() => _ForgetPasswordDialogState();
}
class _ForgetPasswordDialogState extends State<ForgetPasswordDialog> {
final emailController = TextEditingController();
var _isLoading = false;
_showDialog(String title, String message) {
showDialog(
barrierDismissible: false,
context: context,
builder: (ctx) => WillPopScope(
onWillPop: () async => false,
child: new AlertDialog(
elevation: 15,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(8))),
title: Text(
title,
style: TextStyle(color: Colors.white),
),
content: Text(
message,
style: TextStyle(color: Colors.white),
),
backgroundColor: Theme.of(context).primaryColor,
actions: <Widget>[
FlatButton(
child: Text(
'OK',
style: TextStyle(color: Theme.of(context).accentColor),
),
onPressed: () {
Navigator.of(context).pop();
setState(
() {
_isLoading = false;
},
);
},
)
],
),
),
);
}

Future<void> _forgetPassword (String email) async {
try{
setState(() {
_isLoading = true;
}); 
await Provider.of<UserDetailsProvider>(context, listen: false).forgetPassword(email);
print('code are sent via email');
} on HttpException catch (error) {
_showDialog('Authentication Failed', error.message);
} on SocketException catch (_) {
_showDialog('An error occured',
'please check your internet connection and try again later');
} catch (error) {
_showDialog('Authentication Failed',
'Something went wrong, please try again later');
}
setState(() {
_isLoading = false;
});
}
@override
void dispose() {
emailController.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Dialog(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(16)
),
elevation: 8,
backgroundColor: Theme.of(context).accentColor,
child: dialogContent(context),
);
}
dialogContent(BuildContext context){

return Container(
padding: EdgeInsets.only(
top: 50,
right: 16,
left: 16,
bottom: 16,
),
margin: EdgeInsets.all(8),
width: double.infinity,
decoration: BoxDecoration(
color: Theme.of(context).accentColor,
shape: BoxShape.rectangle,
borderRadius: BorderRadius.circular(17),
boxShadow: [
BoxShadow(
color: Colors.black87,
blurRadius: 10.0,
offset: Offset(0.0,10.0),
)
]
),
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Text(
widget.title,
style: TextStyle(
fontSize: 24,
),
),
SizedBox(
height: 20,
),
Text(widget.description, style: TextStyle(fontSize: 16),
),
SizedBox(
height: 20,
),
TextField(
controller: emailController,
style: TextStyle(color: Colors.white),
keyboardType: TextInputType.emailAddress,
decoration: InputDecoration(
border: OutlineInputBorder(
borderSide: BorderSide(color:Theme.of(context).primaryColor)
),
fillColor: Colors.black87,
hintStyle: TextStyle(color:Colors.grey),
hintText: 'please enter your email',
labelText: 'Email',
labelStyle: TextStyle(color:Colors.white)
),  
),
SizedBox(
height: 20,
),
Container(
width: double.infinity,
child: RaisedButton(
child: Text('Send'),
onPressed: (){
_isLoading 
? CircularProgressIndicator()
: print(emailController.text);
_forgetPassword(emailController.text);
Navigator.of(context).pop();
}
),
),
Container(
width: double.infinity,
child: RaisedButton(
child: Text('Cancel'),
onPressed: (){
Navigator.of(context).pop();
}
),
),  
],
),
);
}
}

Answer 1

更换

setState((){});

带有

CCD_ 2。

挂载的检查[State]对象当前是否在树中。这样，你就可以避免这个错误。