当用户第一次启动我的应用时，他可以在注册表单和登录表单之间切换。完成其中一个表单后，他应该会看到加载屏幕，直到创建或登录用户。不幸的是，在我的情况下，尽管创建了用户，但加载屏幕并没有消失。 我该如何解决这个问题？
登录表单：
class SignIn extends StatefulWidget {
final Function toggleView;
SignIn({this.toggleView});
@override
_SignInState createState() => _SignInState();
}
class _SignInState extends State<SignIn> {
final AuthService _auth = AuthService();
final _formKey = GlobalKey<FormState>();
bool loading = false;
// text field state
String email = '';
String password = '';
String error = '';
static const color = const Color(0xFF2F80ED);
@override
Widget build(BuildContext context) {
return loading
? Loading()
: Scaffold(
backgroundColor: Colors.white,
resizeToAvoidBottomInset: false,
body: Stack(
children: <Widget>[
Container(
child: Positioned(
top: 0,
right: 0,
child: Image.asset(
'assets/canvas-1-ws.png',
),
),
),
Positioned(
top: 25.0,
left: 5.0,
child: IconButton(
icon: Icon(
Icons.close,
color: Colors.black,
size: 35.0,
),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Welcome(),
),
);
},
),
),
Container(
child: Positioned(
bottom: 0,
left: 0,
child: Image.asset(
'assets/canvas-2-ws.png',
),
),
),
Center(
child: Stack(
children: <Widget>[
Padding(
padding: EdgeInsets.only(
left: 50.0,
right: 50.0,
),
child: Container(
child: Form(
key: _formKey,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'Login',
style: TextStyle(
color: Colors.black,
fontFamily: 'Roboto Black',
fontSize: 35.0,
),
),
SizedBox(
height: 30.0,
),
TextFormField(
style: TextStyle(
fontFamily: 'Roboto Light',
color: Colors.black,
),
cursorColor: Colors.black,
decoration: InputDecoration(
fillColor: Colors.black,
hintText: 'Email',
hintStyle: TextStyle(
fontFamily: 'Roboto Light',
color: Colors.black,
),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Colors.black,
width: 1.0,
),
),
focusedBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Colors.black,
width: 1.0,
),
),
),
validator: (val) => val.isEmpty
? 'Bitte gültige Email'
: null,
onChanged: (val) {
setState(() => email = val);
},
),
SizedBox(
height: 20.0,
),
TextFormField(
style: TextStyle(
fontFamily: 'Roboto Light',
color: Colors.black,
),
cursorColor: Colors.black,
decoration: InputDecoration(
fillColor: Colors.black,
hintText: 'Passwort',
hintStyle: TextStyle(
fontFamily: 'Roboto Light',
color: Colors.black,
),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Colors.black,
width: 1.0,
),
),
focusedBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Colors.black,
width: 1.0,
),
),
),
obscureText: true,
validator: (val) => val.isEmpty
? 'Bitte gültiges Passwort'
: null,
onChanged: (val) {
setState(() => password = val);
}),
SizedBox(
height: 45.0,
),
ButtonTheme(
minWidth: 200,
height: 50,
child: RaisedButton(
elevation: 0,
color: color,
textColor: Colors.white,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
side: BorderSide(color: color),
),
child: Container(
decoration: BoxDecoration(
boxShadow: [
BoxShadow(
color: color,
spreadRadius: 10.0,
blurRadius: 20.0,
offset: Offset(0, 3),
),
],
),
child: Text(
'Login',
style: TextStyle(
fontFamily: 'Roboto Light',
fontSize: 25.0),
),
),
onPressed: () async {
if (_formKey.currentState.validate()) {
setState(() => loading = true);
dynamic result = await _auth
.signInWithEmailAndPassword(
email, password);
if (result == null) {
setState(() {
error = 'Falsche Email/Password';
loading = false;
});
}
}
},
),
),
],
),
),
),
),
],
),
),
],
),
);
}
}
注册表格几乎相似...
文件，用户可以在其中切换表单：
class Welcome extends StatefulWidget {
final Function toggleView;
Welcome({this.toggleView});
@override
_WelcomeState createState() => _WelcomeState();
}
class _WelcomeState extends State<Welcome> {
static const color = const Color(0xFF2F80ED);
@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: Stack(
children: <Widget>[
Positioned(
top: 0,
right: 0,
child: Image.asset('assets/canvas-1-ws.png'),
),
Positioned(
bottom: 0,
left: 0,
child: Image.asset('assets/canvas-2-ws.png'),
),
Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Image.asset(
'assets/Skiclublogo_transparent.png',
scale: 4,
),
SizedBox(
height: 40.0,
),
ButtonTheme(
minWidth: 200,
height: 50,
child: RaisedButton(
elevation: 0,
color: color,
textColor: Colors.white,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
side: BorderSide(color: color),
),
child: Container(
decoration: BoxDecoration(
boxShadow: [
BoxShadow(
color: color,
spreadRadius: 10.0,
blurRadius: 20.0,
offset: Offset(0, 3),
),
],
),
child: Text(
'Registrieren',
style: TextStyle(
fontFamily: 'Roboto Light', fontSize: 25.0),
),
),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Register(),
),
);
}),
),
SizedBox(
height: 40.0,
),
ButtonTheme(
minWidth: 200,
height: 50,
child: RaisedButton(
elevation: 0,
color: color,
textColor: Colors.white,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
side: BorderSide(color: color),
),
child: Container(
decoration: BoxDecoration(
boxShadow: [
BoxShadow(
color: color,
spreadRadius: 10.0,
blurRadius: 20.0,
offset: Offset(0, 3),
),
],
),
child: Text(
'Login',
style: TextStyle(
fontFamily: 'Roboto Light', fontSize: 25.0),
),
),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => SignIn(),
),
);
}),
),
],
),
),
],
),
);
}
}
auth 文件，用户在其中创建或登录：
class AuthService {
final FirebaseAuth _auth = FirebaseAuth.instance;
// create user obj based on FirrebaseUser
User _userFromFirebaseUser(FirebaseUser user) {
return user != null ? User(uid: user.uid) : null;
}
// auth change user stream
Stream<User> get user {
return _auth.onAuthStateChanged.map(_userFromFirebaseUser);
}
// sign in anonmously
Future signInAnon() async {
try {
AuthResult result = await _auth.signInAnonymously();
FirebaseUser user = result.user;
// create a new document for the user with the uid
await DatabaseService(uid: user.uid).updateUserData(
user.displayName, user.email, user.photoUrl, user.uid);
return _userFromFirebaseUser(user);
} catch (e) {
print(e.toString());
return null;
}
}
// sign in email & password
Future signInWithEmailAndPassword(String email, String password) async {
try {
AuthResult result = await _auth.signInWithEmailAndPassword(
email: email, password: password);
FirebaseUser user = result.user;
return _userFromFirebaseUser(user);
} catch (e) {
print(e.toString());
return null;
}
}
// register with email & password
Future registerWithEmailAndPassword(
String email, String password, String name) async {
try {
AuthResult result = await _auth.createUserWithEmailAndPassword(
email: email, password: password);
FirebaseUser user = result.user;
// update user info
UserUpdateInfo userUpdateInfo = UserUpdateInfo();
userUpdateInfo.displayName = name;
await user.updateProfile(userUpdateInfo);
await user.reload();
user = await FirebaseAuth.instance.currentUser();
// create a new document for the user with the uid
await DatabaseService(uid: user.uid).updateUserData(
user.displayName, user.email, user.photoUrl, user.uid);
return _userFromFirebaseUser(user);
} catch (e) {
print(e.toString());
return null;
}
}
// sign out
Future signOut() async {
try {
return await _auth.signOut();
} catch (e) {
print(e.toString());
return null;
}
}
// current user
void inputData() async {
final FirebaseUser user = await _auth.currentUser();
final uid = user.uid;
// here you write the codes to input the data into firestore
}
}
包装文件，应用程序在其中检查用户是否是新用户：
class Wrapper extends StatelessWidget {
@override
Widget build(BuildContext context) {
final user = Provider.of<User>(context);
print(user);
// return either Home or Authenticate widget
if (user == null) {
return Welcome();
} else {
return DrawerNav();
}
}
}
载入画面文件：
class Loading extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Container(
color: Colors.white,
child: Center(
child: SpinKitWave(
color: Colors.black,
size: 50.0,
),
),
);
}
}
非常感谢您阅读所有内容！
答案 0 :(得分：1)
您并不总是在创建用户后调用 setState。
这会起作用
onPressed: (){ if (_formKey.currentState.validate()) {
setState(() => loading = true);
dynamic result = await _auth
.signInWithEmailAndPassword(
email, password);
setState(() => loading = false);
if (result == null) {
setState(() {
error = 'Falsche Email/Password';
});
}
}},
答案 1 :(得分：0)
我向你解释我的朋友
设置一个名为 loading 的 #include <iostream>
int main() {
usmall foo = 3;
usmall bar = 30;
usmall baz = foo * bar;
std::cout << static_cast<unsigned>(baz) << '\n'; // prints 25
}
变量
booleanif loading = false;
is loading display loading screen else 显示你的表单 ui 使用 true
在创建用户时更改ternary operator的{{1}}，以便加载屏幕出现
state在创建用户后，再次将loading的{{1}}更改为 setState(() { loading=true; });
state这是 loading false
setState(() { loading=false; });