如何在没有上下文的情况下使用提供程序? [英] How can I use provider without context?
问题描述
我在使用提供程序的地方有一个小部件，但是我想在普通小部件中使用值的地方，所以也许任何人都可以提供帮助.
I have a widget where I use the provider but where I want to use the values is in normal widgets so maybe anyone can help.
这是我使用提供程序的地方:
This is where I use the provider :
Widget _buildName(BuildContext context) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(
'Full Name',
style: kLabelStyle3,
),
SizedBox(height: 10.0),
Container(
alignment: Alignment.centerLeft,
height: 50.0,
child: TextFormField(
initialValue: UserData.fullname;
validator: (val) => val.isEmpty ? 'Enter your Name' : null,
onChanged: (val) {
setState(() => _currentfullname = val);
},
style: TextStyle(
color: Colors.black,
fontFamily: 'OpenSans',
),
decoration: InputDecoration(
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.circular(25.0),
borderSide: BorderSide(
color: Colors.black,
width: 2.0,
),
),
contentPadding: EdgeInsets.only(top: 14.0),
prefixIcon: Icon(
Icons.person,
color: Colors.black,
),
hintText: 'Enter your Name',
hintStyle: kHintTextStyle2,
),
),
),
],
);
}
@override
Widget build(BuildContext context) {
final user = Provider.of<Userr>(context);
return StreamBuilder<UserData>(
stream: DatbaseService(uid:user.uid).userData,
builder: (context, snapshot) {
if(snapshot.hasData){
UserData userData =snapshot.data;
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.transparent,
elevation: 0.0,
),
body: AnnotatedRegion<SystemUiOverlayStyle>(
value: SystemUiOverlayStyle.light,
child: GestureDetector(
onTap: () => FocusScope.of(context).unfocus(),
child: Form(
key: _formKey,
child: Stack(
children: <Widget>[
Container(
height: double.infinity,
child: SingleChildScrollView(
physics: AlwaysScrollableScrollPhysics(),
padding: EdgeInsets.symmetric(
horizontal: 40.0,
vertical: 10,
),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Center(
child: Stack(
children: [
Container(
width: 110,
height: 110,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(100),
image: DecorationImage(
fit: BoxFit.cover,
image: NetworkImage(
"https://images.pexels.com/photos/3307758/pexels-photo-3307758.jpeg?auto=compress&cs=tinysrgb&dpr=3&h=250",
))),
),
Positioned(
bottom: 0,
right: 0,
child: Container(
height: 35,
width: 35,
decoration: BoxDecoration(
shape: BoxShape.circle,
border: Border.all(
width: 4,
color: Theme.of(context)
.scaffoldBackgroundColor,
),
color: Colors.green,
),
child: Icon(
Icons.edit,
color: Colors.white,
),
)),
],
),
),
SizedBox(
height: 10,
),
Text(
'Mein Profil',
style: TextStyle(
color: Colors.black,
fontFamily: 'OpenSans',
fontSize: 20.0,
fontWeight: FontWeight.w600,
),
),
showAlert2(),
_buildEmailTF(),
SizedBox(
height: 30.0,
),
_buildName(),
SizedBox(
height: 30.0,
),
_builduserName(),
SizedBox(
height: 30.0,
),
_buildPasswordTF(),
SizedBox(height: 30,),
_buildPassword2TF(),
_buildUpdateDataButton(),
// _buildEmailform(),
],
),
),
)
],
),
),
),
),
);
}else{
return null;
}
}
);
}
}
class DatbaseService{
final String uid;
DatbaseService({this.uid});
//collection reference
final CollectionReference myprofilsettings = FirebaseFirestore.instance.collection('meinprofilsettings');
Future updateUserData(String user,String fullname,String password,String email)async{
return await myprofilsettings.doc(uid).set({
'username':user,
'fullname':fullname,
'passwort':password,
'email':email,
});
}
//profil list from snapshot
List<myprofil> _myprofillistFromSnapshot(QuerySnapshot snapshot){
return snapshot.docs.map((doc){
return myprofil(
user: doc.data()['user']??'',
fullname: doc.data()['fullname']??'',
email: doc.data()['email']??'',
passowrd: doc.data()['password']??'',
);
}).toList();
}
//userData from snapshot
UserData _userDataFromSnapshot(DocumentSnapshot snapshot){
return UserData(
uid: uid,
name: snapshot.data()['name'],
fullname: snapshot.data()['fullname'],
email: snapshot.data()['email'],
password: snapshot.data()['password'],
);
}
//get myprofilsettings stream
Stream<List<myprofil>> get settings{
return myprofilsettings.snapshots().map(_myprofillistFromSnapshot);
}
//get user doc stream
Stream<UserData> get userData{
return myprofilsettings.doc(uid).snapshots().map(_userDataFromSnapshot);
}
}
import 'package:flutter/cupertino.dart';
class Userr{
final String uid;
Userr({this.uid});
}
class UserData {
final String uid;
final String user;
final String fullname;
final String email;
final String passowrd;
UserData({this.uid,this.user,this.fullname,this.email,this.passowrd, name, password});
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======== Exception caught by widgets library =======================================================
The following assertion was thrown building StreamBuilder<UserData>(dirty, state: _StreamBuilderBaseState<UserData, AsyncSnapshot<UserData>>#c612d):
A build function returned null.
The offending widget is: StreamBuilder<UserData>
Build functions must never return null.
To return an empty space that causes the building widget to fill available room, return "Container()". To return an empty space that takes as little room as possible, return "Container(width: 0.0, height: 0.0)".
The relevant error-causing widget was:
StreamBuilder<UserData> file:///Users/name/StudioProjects/project/lib/seitenleiste/meinacount.dart:356:16
When the exception was thrown, this was the stack:
#0 debugWidgetBuilderValue.<anonymous closure> (package:flutter/src/widgets/debug.dart:305:7)
#1 debugWidgetBuilderValue (package:flutter/src/widgets/debug.dart:326:4)
#2 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4592:7)
#3 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4759:11)
#4 Element.rebuild (package:flutter/src/widgets/framework.dart:4281:5)
...
====================================================================================================
推荐答案
我假设您的 _buildName()是窗口小部件的方法，并且您从某个地方的build方法调用它.
I’m assuming that your _buildName() is a method of your widget and that you call it from you build method somewhere.
这意味着您可以将上下文或用户传递给此方法: _buildName(BuildContext上下文){} 或 _buildName(用户){}
This means that you can pass either the context or the user into this method:
_buildName(BuildContext context) {} or _buildName(User user) {}
下次尝试提供更多代码，尤其是调用该方法的部分.
Try providing more of the code next time, specifically the parts where you call the method.
帖子更新后
您需要在buildName方法中具有用户对象，以便您不能简单地执行 UserData.fullname ，因为 UserData 是一个类而不是实例.
You need to have the user object in the buildName method so you cannot simply do UserData.fullname because UserData is a class not an instance.
因此要在buildName中获取数据，您需要将其更改为:
So to get your data in the buildName you need to change it to:
_buildName(UserData userData) {
userData.fullname; // this now exists
}
调用类似于: _buildName(userData)
这篇关于如何在没有上下文的情况下使用提供程序?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
