How sort questions and fix error: Flutter? - flutter

Question

I have quiz app (flutter+Firebase), but I want to sort by question(1) not by question id(2). or hot to rename questions id in firebase?
what should I change in my code? Is there any way to do it?
and how to fix this error?
.dart
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:quiz2/database/firebase.dart';
import 'package:quiz2/model/question.dart';
import 'package:quiz2/screens/words/results.dart';
import 'package:quiz2/widgets/play.dart';
class QuizPlay extends StatefulWidget {
final String quizId;
QuizPlay(this.quizId);
#override
_QuizPlayState createState() => _QuizPlayState();
}
int _correct = 0;
int _incorrect = 0;
int _notAttempted = 0;
int total = 0;
/// Stream
Stream infoStream;
class _QuizPlayState extends State<QuizPlay> {
QuerySnapshot questionSnaphot;
DatabaseService databaseService = new DatabaseService();
bool isLoading = true;
#override
void initState() {
databaseService.getQuizData(widget.quizId).then((value) {
questionSnaphot = value;
_notAttempted = questionSnaphot.docs.length;
_correct = 0;
_incorrect = 0;
isLoading = false;
total = questionSnaphot.docs.length;
setState(() {});
print("init don $total ${widget.quizId} ");
});
if (infoStream == null) {
infoStream = Stream<List<int>>.periodic(Duration(milliseconds: 100), (x) {
print("this is x $x");
return [_correct, _incorrect];
});
}
super.initState();
}
QuestionModel getQuestionModelFromDatasnapshot(
DocumentSnapshot questionSnapshot) {
QuestionModel questionModel = new QuestionModel();
questionModel.question = questionSnapshot["question"];
/// shuffling the options
List<String> options = [
questionSnapshot["option1"],
questionSnapshot["option2"],
questionSnapshot["option3"],
questionSnapshot["option4"]
];
options.shuffle();
questionModel.option1 = options[0];
questionModel.option2 = options[1];
questionModel.option3 = options[2];
questionModel.option4 = options[3];
questionModel.correctOption = questionSnapshot["option1"];
questionModel.answered = false;
print(questionModel.correctOption.toLowerCase());
return questionModel;
}
#override
void dispose() {
infoStream = null;
super.dispose();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Align(
child: Text("#ЄВІ_ПІДГОТОВКА"),
alignment: Alignment.center,
),
),
body: isLoading
? Container(
child: Center(child: CircularProgressIndicator()),
)
: SingleChildScrollView(
child: Container(
child: Column(
children: [
InfoHeader(
length: questionSnaphot.docs.length,
),
SizedBox(
height: 10,
),
questionSnaphot.docs == null
? Container(
child: Center(
child: Text("No Data"),
),
)
: ListView.builder(
itemCount: questionSnaphot.docs.length,
shrinkWrap: true,
physics: ClampingScrollPhysics(),
itemBuilder: (context, index) {
return QuizPlayTile(
questionModel: getQuestionModelFromDatasnapshot(
questionSnaphot.docs[index]),
index: index,
);
})
],
),
),
),
floatingActionButton: FloatingActionButton(
child: Icon(Icons.check),
onPressed: (){
Navigator.pushReplacement(context, MaterialPageRoute(
builder: (contex) => Results(
correct: _correct,
incorrect: _incorrect,
total: total,
) ));
},)
);
}
}
class InfoHeader extends StatefulWidget {
final int length;
InfoHeader({#required this.length});
#override
_InfoHeaderState createState() => _InfoHeaderState();
}
class _InfoHeaderState extends State<InfoHeader> {
#override
Widget build(BuildContext context) {
return StreamBuilder(
stream: infoStream,
builder: (context, snapshot) {
return snapshot.hasData
? Container(
height: 40,
margin: EdgeInsets.only(left: 14),
child: ListView(
scrollDirection: Axis.horizontal,
shrinkWrap: true,
children: <Widget>[
NoOfQuestionTile(
text: "Total",
number: widget.length,
),
NoOfQuestionTile(
text: "Correct",
number: _correct,
),
NoOfQuestionTile(
text: "Incorrect",
number: _incorrect,
),
NoOfQuestionTile(
text: "NotAttempted",
number: _notAttempted,
),
],
),
)
: Container();
});
}
}
class QuizPlayTile extends StatefulWidget {
final QuestionModel questionModel;
final int index;
QuizPlayTile({#required this.questionModel, #required this.index});
#override
_QuizPlayTileState createState() => _QuizPlayTileState();
}
class _QuizPlayTileState extends State<QuizPlayTile> {
String optionSelected = "";
#override
Widget build(BuildContext context) {
return Container(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Container(
margin: EdgeInsets.symmetric(horizontal: 20),
child: Text(
"Q${widget.index + 1}. ${widget.questionModel.question}",
style:
TextStyle(fontSize: 18, color: Colors.black.withOpacity(0.8)),
),
),
SizedBox(
height: 12,
),
GestureDetector(
onTap: () {
if (!widget.questionModel.answered) {
///correct
if (widget.questionModel.option1 ==
widget.questionModel.correctOption) {
setState(() {
optionSelected = widget.questionModel.option1;
widget.questionModel.answered = true;
_correct = _correct + 1;
_notAttempted = _notAttempted - 1;
});
} else {
setState(() {
optionSelected = widget.questionModel.option1;
widget.questionModel.answered = true;
_incorrect = _incorrect + 1;
_notAttempted = _notAttempted - 1;
});
}
}
},
child: OptionTile(
option: "A",
description: "${widget.questionModel.option1}",
correctAnswer: widget.questionModel.correctOption,
optionSelected: optionSelected,
),
),
SizedBox(
height: 4,
),
GestureDetector(
onTap: () {
if (!widget.questionModel.answered) {
///correct
if (widget.questionModel.option2 ==
widget.questionModel.correctOption) {
setState(() {
optionSelected = widget.questionModel.option2;
widget.questionModel.answered = true;
_correct = _correct + 1;
_notAttempted = _notAttempted - 1;
});
} else {
setState(() {
optionSelected = widget.questionModel.option2;
widget.questionModel.answered = true;
_incorrect = _incorrect + 1;
_notAttempted = _notAttempted - 1;
});
}
}
},
child: OptionTile(
option: "B",
description: "${widget.questionModel.option2}",
correctAnswer: widget.questionModel.correctOption,
optionSelected: optionSelected,
),
),
SizedBox(
height: 4,
),
GestureDetector(
onTap: () {
if (!widget.questionModel.answered) {
///correct
if (widget.questionModel.option3 ==
widget.questionModel.correctOption) {
setState(() {
optionSelected = widget.questionModel.option3;
widget.questionModel.answered = true;
_correct = _correct + 1;
_notAttempted = _notAttempted - 1;
});
} else {
setState(() {
optionSelected = widget.questionModel.option3;
widget.questionModel.answered = true;
_incorrect = _incorrect + 1;
_notAttempted = _notAttempted - 1;
});
}
}
},
child: OptionTile(
option: "C",
description: "${widget.questionModel.option3}",
correctAnswer: widget.questionModel.correctOption,
optionSelected: optionSelected,
),
),
SizedBox(
height: 4,
),
GestureDetector(
onTap: () {
if (!widget.questionModel.answered) {
///correct
if (widget.questionModel.option4 ==
widget.questionModel.correctOption) {
setState(() {
optionSelected = widget.questionModel.option4;
widget.questionModel.answered = true;
_correct = _correct + 1;
_notAttempted = _notAttempted - 1;
});
} else {
setState(() {
optionSelected = widget.questionModel.option4;
widget.questionModel.answered = true;
_incorrect = _incorrect + 1;
_notAttempted = _notAttempted - 1;
});
}
}
},
child: OptionTile(
option: "D",
description: "${widget.questionModel.option4}",
correctAnswer: widget.questionModel.correctOption,
optionSelected: optionSelected,
),
),
SizedBox(
height: 20,
),
],
),
);
}
}
Is there any way to do it? In case you want to see the code please let me know I will update more.
Is there any way to do it? In case you want to see the code please let me know I will update more.

Answer 1

It all comes back to how you save your data.
Can questions be shared between quizzes
here are sample db diagram
If your Questions can be shared between quizzes you might want to have a collection with all the quizzes and another with questions and tag each question with a quizID, and its no/ occurrence.
How To query for this, get a quiz ID and fetch all questions for where quizID match and order by no/ occurrence
so your db would look something like this
collectionQUiz-|_quiz0
|_quiz1
|_quiz2-|-quizId,
|-timestamp //always good to use for querying
collectionQuestions-|q1d-|quizId
|-other prams
|q2d-|quizId
|-other prams
querying questions you can use timestamps, We cant see how you create the questions, my guess, you are either creating one question at a time, uploading using a for loop,sending a list, if you add a timestamp key to your question object, you can use it to query for the first added question for that quiz.
Else the one creating a quiz can number the questions ,or you number them before uploading , and save the value in the db and use it to sort
I think this would be a better approach, with firestore indexing , your database should handle this easily