颤振错误:此小部件已卸载，因此状态不再具有上下文(应视为已失效) [英] flutter error: This widget has been unmounted, so the State no longer has a context (and should be considered defunct)
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问题描述
当我点击登录按钮时我的手机号码错误然后打开一个错误对话框，然后当我点击对话框上的 okey 时出现此错误.
when I clicking on login button when my mobile number is wrong then open one error dialog box after that when I clicked okey on dialog box then i got this error.
我收到了这条消息
此小部件已卸载，因此 State 不再具有上下文(并且应该被认为是不复存在的)
This widget has been unmounted, so the State no longer has a context (and should be considered defunct)
考虑在处置"期间取消任何活动的工作.或使用安装"getter 来确定 State 是否仍然处于活动状态.
Consider canceling any active work during "dispose" or using the "mounted" getter to determine if the State is still active.
class _LoginPageState extends State<LoginPage> {
final GlobalKey<FormState> _formKey = GlobalKey();
TextEditingController _mobileController = new TextEditingController();
// TextEditingController _nameController = new TextEditingController();
// TextEditingController _emailController = new TextEditingController();
TextEditingController _passwordController = new TextEditingController();
Map<String, String> _authData = {
'user_name': '',
'user_email': '',
'username': '',
'password': ''
};
Future _submit() async {
print('aa' + _authData['username']);
if (!_formKey.currentState.validate()) {
return;
}
_formKey.currentState.save();
try {
await Provider.of<Auth>(context, listen: false).login(
_authData['user_name'],
_authData['user_email'],
_authData['username'],
_authData['password']);
print('authData_username' + _authData['username']);
print('authData_password' + _authData['password']);
} on HttpException catch (e) {
// } catch (e) {
var errorMessage = 'Authentication Failed';
if (e.toString().contains('Entered wrong mobile number!')) {
errorMessage = 'Entered wrong mobile number!';
print(errorMessage);
_showerrorDialog(errorMessage);
} else if (e.toString().contains('Entered wrong password!')) {
errorMessage = 'Entered wrong password!';
_showerrorDialog(errorMessage);
}
} catch (error) {
var errorMessage = 'Please try again later';
_showerrorDialog(errorMessage);
}
}
@override
void dispose() {
// TODO: implement dispose
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: ListView(
children: <Widget>[
Container(
width: MediaQuery.of(context).size.width,
height: MediaQuery.of(context).size.height / 3.5,
decoration: BoxDecoration(
gradient: LinearGradient(
begin: Alignment.topCenter,
end: Alignment.bottomCenter,
colors: myGradient2),
borderRadius:
BorderRadius.only(bottomLeft: Radius.circular(90))),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Spacer(),
Align(
alignment: Alignment.center,
child: Icon(
Icons.person,
size: 90,
color: kWhite,
),
),
Spacer(),
Align(
alignment: Alignment.bottomRight,
child: Padding(
padding: const EdgeInsets.only(bottom: 32, right: 32),
child: Text(
'Login',
style: TextStyle(color: kWhite, fontSize: 18),
),
),
),
],
),
),
Container(
height: MediaQuery.of(context).size.height / 2,
width: MediaQuery.of(context).size.width,
padding: EdgeInsets.only(top: 62),
child: Form(
key: _formKey,
child: Column(
children: <Widget>[
Container(
width: MediaQuery.of(context).size.width / 1.2,
// height: 45,
child: TextFormField(
keyboardType: TextInputType.name,
autofocus: false,
decoration: InputDecoration(
hintText: 'Username.',
contentPadding:
EdgeInsets.fromLTRB(20.0, 15.0, 20.0, 15.0),
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(32.0)),
),
validator: (input) =>
input.length > 10 || input.length < 10
? "Mobile Number should be valid"
: null,
controller: _mobileController,
onSaved: (value) {
_authData['username'] = value;
},
// maxLength: 10,
),
),
SizedBox(
height: 10,
),
Container(
width: MediaQuery.of(context).size.width / 1.2,
// height: 45,
child: TextFormField(
keyboardType: TextInputType.text,
autofocus: false,
obscureText: true,
decoration: InputDecoration(
hintText: 'Password',
contentPadding:
EdgeInsets.fromLTRB(20.0, 15.0, 20.0, 15.0),
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(32.0)),
),
validator: (input) => input.length < 3
? "Password should be more than 3 characters"
: null,
controller: _passwordController,
onSaved: (value) {
_authData['password'] = value;
},
),
),
Align(
alignment: Alignment.centerRight,
child: Padding(
padding: const EdgeInsets.only(top: 16, right: 32),
child: Text(
'Forgot Password ?',
style: TextStyle(color: Colors.grey),
),
),
),
Spacer(),
InkWell(
onTap: () {
_submit();
},
child: Container(
height: 45,
width: MediaQuery.of(context).size.width / 1.2,
decoration: BoxDecoration(
gradient: LinearGradient(
colors: myGradient2,
),
borderRadius:
BorderRadius.all(Radius.circular(50))),
child: Center(
child: Text(
'Login'.toUpperCase(),
style: TextStyle(
color: Colors.white,
fontWeight: FontWeight.bold),
),
),
),
),
],
),
),
),
SizedBox(
height: 50,
),
InkWell(
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text("Dnon't have an account ?"),
Text(
"Sign Up",
style: TextStyle(color: kGreen),
),
],
),
onTap: () {
// Navigator.pushNamed(context, '/signup');
Navigator.push(
context,
MaterialPageRoute(builder: (context) => SignupPage()),
);
},
),
],
),
),
);
}
void _showerrorDialog(String message) {
showDialog(
context: context,
builder: (ctx) => AlertDialog(
title: Text(
'An Error Occurs',
style: TextStyle(color: Colors.blue),
),
content: Text(message),
actions: <Widget>[
FlatButton(
child: Text('Okay'), onPressed: () => Navigator.of(mounted).pop())
],
),
);
}
}
推荐答案
尝试使用
Navigator.pop() 或 Navigator.of(context, rootNavigator: true).pop()
Navigator.pop() or Navigator.of(context, rootNavigator: true).pop()
而不是 Navigator.of(mounted).pop()) 来关闭 Dialog 窗口.
instead of Navigator.of(mounted).pop()) to close Dialog window.
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