type 'Null' is not a subtype of type 'File' of 'image' flutter problem - flutter

Question

I uploaded my image to FireStore. When I am creating an image it's perfectly ok everything uploading perfectly. After SignUp I can easily go to the user profile and can see the user name and email. But when I log out from the user profile and from my LOGIN from when providing existing email and password which I have created already then the Exception is thrown. I am not getting the issue. Exception has occurred.
_TypeError (type 'Null' is not a subtype of type 'File' of 'image')
import 'dart:io';
import '../picker/user_image_picker.dart';
import 'package:flutter/material.dart';
class AuthForm extends StatefulWidget {
AuthForm(this.submitFn, this.isLoading);
final bool isLoading;
var submitFn;
void function(
String email,
String password,
String userName,
File image,
bool isLogin,
BuildContext ctx,
);
#override
_AuthFormState createState() => _AuthFormState();
#override
noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
}
class _AuthFormState extends State<AuthForm> {
final _formKey = GlobalKey<FormState>();
var _isLogin = true;
var _userEmail = '';
var _userName = '';
var _userPasssword = '';
File? userImageFile;
void pickedImage(File image) {
userImageFile = image;
}
void _trySubmit() {
final isValid = _formKey.currentState!.validate();
FocusScope.of(context).unfocus();
if (userImageFile == null && !_isLogin) {
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(
content: Text('Please Pick an Image.'),
backgroundColor: Theme.of(context).errorColor,
),
);
return;
}
if (isValid) {
_formKey.currentState?.save();
print(_userEmail);
print(_userName);
print(_userPasssword);
print(' Good to go ');
widget.submitFn(
_userEmail.trim(),
_userPasssword.trim(),
_userName.trim(),
userImageFile,
_isLogin,
context,
);
} else {
print('Form is not valid');
}
}
#override
Widget build(BuildContext context) {
return Card(
margin: EdgeInsets.all(20),
child: SingleChildScrollView(
child: Padding(
padding: EdgeInsets.all(16),
child: Form(
key: _formKey,
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
if (!_isLogin) UserImagePicker(pickedImage),//this is my image file
TextFormField(
key: ValueKey('email'),
onSaved: (value) {
_userEmail = value!;
},
validator: (value) {
if (value!.isEmpty ||
!value.contains(RegExp(
'^[a-zA-Z0-9+_.-]+#[a-zA-Z0-9.-]+.[a-z]+.[com]'))) {
return 'enter valid Email';
//print('Email validation is not ok');
} else {
return null;
}
},
keyboardType: TextInputType.emailAddress,
decoration: InputDecoration(
labelText: 'Email Address', icon: Icon(Icons.email)),
),
if (!_isLogin)
TextFormField(
key: ValueKey('userName'),
onSaved: (value) {
_userName = value!;
},
validator: (value) {
if (value == null || value.length < 4) {
return 'Enter At least 4 charaters ';
}
return null;
},
decoration: InputDecoration(
labelText: 'User Name', icon: Icon(Icons.person)),
),
TextFormField(
key: ValueKey('password'),
onSaved: (value) {
_userPasssword = value!;
},
obscureText: true,
validator: (value) {
if (value == null || value.isEmpty || value.length < 7) {
return 'Enter at least 7 Digits';
}
return null;
},
decoration: InputDecoration(
labelText: 'Password',
icon: Icon(
Icons.security,
),
),
),
SizedBox(
height: 20,
),
if (widget.isLoading) CircularProgressIndicator(),
if (!widget.isLoading)
ElevatedButton(
child: Text(_isLogin ? 'Login' : 'Signup'),
onPressed: _trySubmit,
),
if (widget.isLoading) CircularProgressIndicator(),
if (!widget.isLoading)
TextButton(
style: TextButton.styleFrom(
primary: Theme.of(context).primaryColor,
),
child: Text(_isLogin
? 'Create New Account'
: 'I already have an account'),
onPressed: () {
setState(
() {
_isLogin = !_isLogin;
},
);
},
)
],
),
),
),
),
);
}
}

Answer 1

Looks like userImageFile is null. This happen because this variable is nullable, and when it gets passed to submitFn (which weirdly is a dynamic variable...?) it throws, because it expects a non-nullable image parameter.