我有以下问题，但无法解决……我正在构建某种问答(是/否(应用程序，并希望实现如果按下按钮(给出答案(，按钮将以颜色突出显示。因此，如果用户返回到上一个按钮，他可以看到自己给出的答案。现在就是这样，所有的问题都来自于结构的火球
final CollectionReference _questionsCollectionReference =
FirebaseFirestore.instance
.collection("content")
.doc(content)
.collection("block")
.doc(block)
.collection("questions");
如果用户回答了一个问题，它将保存在下的用户配置文件中
final firestoreInstance = FirebaseFirestore.instance;
await firestoreInstance
.collection("users")
.doc(user!.id)
.collection("content")
.doc(content)
.collection("block")
.doc(block)
.collection("questions")
.doc(question)
.set({
"answer": answer, //FieldValue.arrayUnion([someData]),
}).then((_) {
print("success!");
});
现在基本上应该是这样的，如果用户路径中的答案=="；是"；，将"；是"；按钮question_view.dart在这里，我们使用PageViewBuilder构建视图，并为其提供QuestionItem
import 'package:fbapp/ui/shared/ui_helpers.dart';
import 'package:fbapp/ui/widgets/question_item.dart';
import 'package:fbapp/viewmodels/questions_view_model.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:stacked/stacked.dart';
class QuestionsView extends StatelessWidget {
final String block;
final String content;
const QuestionsView({Key? key, required this.block, required this.content})
: super(key: key);
@override
Widget build(BuildContext context) {
return ViewModelBuilder<QuestionsViewModel>.reactive(
viewModelBuilder: () => QuestionsViewModel(),
onModelReady: (model) => model.fetchPosts(content, block),
builder: (context, model, child) => Scaffold(
backgroundColor: Colors.white,
body: Padding(
padding: const EdgeInsets.symmetric(horizontal: 10),
child: Column(
mainAxisSize: MainAxisSize.max,
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
verticalSpace(35),
Row(
children: <Widget>[
SizedBox(
height: 80,
child: Image.asset('assets/images/logo.png'),
),
],
),
Expanded(
child: model.questions != null
? Center(
child: Container(
width: 700,
height: 450,
child: PageView.builder(
controller: model.getPageController(),
scrollDirection: Axis.vertical,
itemCount: model.questions!.length,
itemBuilder: (context, index) =>
QuestionItem(
question: model.questions![index],
content: content,
block: block,
nextPage: model.nextPage,
saveCurrentUserAnswer:
model.saveCurrentUserAnswer,
getCurrentUserAnswer:
model.getCurrentUserAnswer),
),
),
)
: Center(
child: CircularProgressIndicator(
valueColor: AlwaysStoppedAnimation(
Theme.of(context).primaryColor),
),
))
],
),
),
));
}
}
question_item.dart
import 'package:fbapp/app/app.locator.dart';
import 'package:fbapp/models/question.dart';
import 'package:flutter/material.dart';
import 'package:stacked_services/stacked_services.dart';
class QuestionItem extends StatelessWidget {
final Question? question;
final String? content;
final String? block;
final String? id;
final void Function()? nextPage;
final Future Function(
String content, String block, String? the question, String answer)?
saveCurrentUserAnswer;
final Future Function(String content, String block, String? question)?
getCurrentUserAnswer;
const QuestionItem(
{Key? key,
this.question,
this.nextPage,
this.saveCurrentUserAnswer,
this.content,
this.block,
this.id,
this.getCurrentUserAnswer})
: super(key: key);
@override
Widget build(BuildContext context) {
return Flex(
direction: Axis.horizontal,
children: [
Expanded(
child: Card(
child: Column(
mainAxisSize: MainAxisSize.min,
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Container(
width: MediaQuery.of(context).size.width * 0.6,
child: ListTile(
leading: Icon(Icons.security),
trailing: IconButton(
icon: Icon(Icons.info),
onPressed: () {
final DialogService _dialogService =
locator<DialogService>();
_dialogService.showDialog(
dialogPlatform: DialogPlatform.Material,
title: "Info",
description: question!.info);
},
),
subtitle: Text("some nice text"),
title: Text(question!.q!),
),
),
const SizedBox(height: 50),
Row(
mainAxisSize: MainAxisSize.min,
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Container(
margin: EdgeInsets.all(10),
height: 50.0,
child: SizedBox.fromSize(
size: Size(50, 50), // button width and height
child: ClipOval(
child: Material(
color: "yes" ==
getCurrentUserAnswer!(
content!, block!, question!.id)
.toString()
? Color.fromRGBO(0, 144, 132, 1)
: Colors.grey, // button color
child: InkWell(
splashColor: Color.fromRGBO(0, 144, 132, 1),
// splash color
onTap: () {
nextPage!();
saveCurrentUserAnswer!(
content!, block!, question!.id, "yes");
},
// button pressed
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.thumb_up,
color: Colors.white,
), // icon
Text(
"Yes",
style: TextStyle(
fontSize: 15,
color: Colors.white,
),
), // text
],
),
),
),
),
),
),
const SizedBox(width: 100, height: 100),
Container(
margin: EdgeInsets.all(10),
height: 50.0,
child: SizedBox.fromSize(
size: Size(50, 50), // button width and height
child: ClipOval(
child: Material(
color: "no" ==
getCurrentUserAnswer!(
content!, block!, question!.id)
.toString()
? Color.fromRGBO(0, 144, 132, 1)
: Colors.grey, // button colorr
child: InkWell(
splashColor: Color.fromRGBO(0, 144, 132, 1),
// splash color
onTap: () {
nextPage!();
saveCurrentUserAnswer!(
content!, block!, question!.id, "no");
},
// button pressed
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.thumb_down,
color: Colors.white,
), // icon
Text(
"No",
style: TextStyle(
fontSize: 15,
color: Colors.white,
),
), // text
],
),
),
),
),
),
),
],
)
],
),
),
),
],
);
}
}
这就是我用"；是"；以及"；否"；按钮。这是question_view_model.dart，我们在其中引用firebase函数来保存并获得如下答案：
...
Future saveCurrentUserAnswer(
String content, String block, String? question, String answer) async {
await _fireStoreService!.saveCurrentUserAnswer(
_authenticationService!.currentUser, content, block, question, answer);
}
Future getCurrentUserAnswer(
String content, String block, String? question) async {
await _fireStoreService!.getCurrentUserAnswer(
_authenticationService!.currentUser, content, block, question);
}
...
而火球的作用是：
...
Future saveCurrentUserAnswer(User? user, String content, String block,
String? question, String answer) async {
final firestoreInstance = FirebaseFirestore.instance;
await firestoreInstance
.collection("users")
.doc(user!.id)
.collection("content")
.doc(content)
.collection("block")
.doc(block)
.collection("questions")
.doc(question)
.set({
"answer": answer, //FieldValue.arrayUnion([someData]),
}).then((_) {
print("success!");
});
}
Future<String> getCurrentUserAnswer(
User? user, String content, String block, String? question) async {
String answer = "";
try {
final DocumentReference _answerCollectionReference = FirebaseFirestore
.instance
.collection("users")
.doc(user!.id)
.collection("content")
.doc(content)
.collection("block")
.doc(block)
.collection("questions")
.doc(question);
var answerDocumentSnapshot = await _answerCollectionReference;
await answerDocumentSnapshot.get().then((a) {
if (a.exists) {
answer = a["answer"];
} else {
answer = "";
}
});
print("Answer: $answer");
return answer;
} catch (e) {
return e.toString();
}
}
...
getCurrentUserAnswer成功打印答案(总是2次，不确定为什么…(
Cont: 00_DSGVO -- Block: b1
2
Answer: no
2
Answer: yes
success!
但是按钮永远不会改变颜色。我也用Stateful和setState、Stateless和ValueNotifier尝试过，但不知怎么的，它不起作用。一个问题是，它必须首先检查是否有答案，而不是重建UI(或只重建按钮(，但它首先构建UI，然后检查答案。。。
我在一些帮助下找到了答案，答案是使用FuturBuilder来包装question_item，并将future设置为getCurrentUserAnswer。
return FutureBuilder(
future: getCurrentUserAnswer!(content!, block!, question!.id),
builder: (BuildContext context, AsyncSnapshot snapshot) { return Flex(...