flutter firestore - How to retrieve the new document id after adding to firestore - flutter

Question

I want to retrieve the new created document id and display the document data in a new page. How can i get the document id? When onPressed() the elevated button, I want to retrieve the document data based on its id.
How can I bring the document id from addDiagnose(_type, _symptomsResult) so that I can navigate it to another page.
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => DiagnosisPage(documentId: documentId),
)
);
This is my current code.
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:multiselect_formfield/multiselect_formfield.dart';
import 'package:petbuddies/user/diagnosis/diagnose_history.dart';
import 'package:petbuddies/user/diagnosis/diagnosis.dart';
class CheckerPage extends StatefulWidget {
const CheckerPage({Key? key}) : super(key: key);
#override
_CheckerPageState createState() => _CheckerPageState();
}
class _CheckerPageState extends State<CheckerPage> {
//retrieve options
final _formKey = GlobalKey<FormState>();
void _petTypeDropDownItemSelected(String newValueSelected) {
setState(() {
petType = newValueSelected;
});
}
clearText(){
_symptoms?.clear();
}
#override
void initState(){
super.initState();
_symptoms = [];
_symptomsResult = [];
}
List? _symptoms;
late List<dynamic> _symptomsResult;
var petType;
var _type;
final Stream<QuerySnapshot> petTypeStream = FirebaseFirestore.instance.collection('pet type').orderBy('name').snapshots();
final Stream<QuerySnapshot> symptomsStream = FirebaseFirestore.instance.collection('symptoms').orderBy('name').snapshots();
DocumentReference diagnosis = FirebaseFirestore.instance.collection('diagnosis').doc();
//store the diagnosis result
User? user = FirebaseAuth.instance.currentUser;
Future<void> addDiagnose(_type, _symptomsResult) async {
String petChosen = this._type;
List symptomsChosen = this._symptomsResult.toList();
QuerySnapshot<Map<String, dynamic>> snapshot =
await FirebaseFirestore.instance.collection("disease")
.where('petType',isEqualTo: petChosen)
.where('symptoms',arrayContainsAny: symptomsChosen)
.get();
List<String> diseaseRef = snapshot.docs.map((e) => e.id).toList();
String createdby = user!.uid;
Timestamp date = Timestamp.now();
List possibleDisease = diseaseRef.toList();
final data = {
'created by': createdby,
'date': date,
'pet chosen': petChosen,
'symptoms chosen': symptomsChosen,
'possible disease': possibleDisease,
};
//set document data
return diagnosis
.set(data)
.then((value) => print('Diagnose Report Added'))
.catchError((error)=>print("Failed to add: $error")
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.blue[900],
title: const Text("Pet Symptoms Checker",
style: TextStyle(color: Colors.white),
),
),
body: Form(
key: _formKey,
child: Padding(
padding: const EdgeInsets.symmetric(vertical: 20, horizontal: 30),
child: ListView(
children: [
Align(
alignment: Alignment.bottomRight,
child: TextButton(
child: const Text(
'History',
style: TextStyle(fontSize: 18),
),
onPressed: (){
Navigator.push(context, MaterialPageRoute(builder: (context) => const DiagnoseHistoryPage(),));
},
),
),
Container(
padding: const EdgeInsets.all(12.0),
decoration: BoxDecoration(
border: Border.all(width: 3, color: Colors.indigo,),
borderRadius: const BorderRadius.all(Radius.circular(30)),
),
child: Column(
children: [
StreamBuilder<QuerySnapshot>(
stream: petTypeStream,
builder: (context, snapshot) {
if (!snapshot.hasData) {
return const Center(
child: CircularProgressIndicator(),
);
}
return Container(
padding: const EdgeInsets.only(bottom: 16.0),
child: Row(
children: <Widget>[
Expanded(
flex: 2,
child: Container(
padding: const EdgeInsets.fromLTRB(12.0, 10.0, 10.0, 10.0),
child: const Text(
"Pet Type",
style: TextStyle(fontSize: 20),
),
),
),
Expanded(
flex: 3,
child: Row(
children: [
const SizedBox(width: 30,),
DropdownButton(
value: petType,
onChanged: (valueSelectedByUser) {
_petTypeDropDownItemSelected(valueSelectedByUser.toString());
},
hint: const Text('Choose Pet Type',),
underline: Container(),
items: snapshot.data!.docs.map((DocumentSnapshot document) {
return DropdownMenuItem<String>(
value: document.get('name'),
child: Text(document.get('name')),
);
}).toList(),
),
],
),
),
],
),
);
}),
StreamBuilder(
stream: symptomsStream,
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot){
if(snapshot.hasError){
print('Something went wrong');
}
if(snapshot.connectionState == ConnectionState.waiting){
return const Center(
child: CircularProgressIndicator(),
);
}
final List symptomsList = [];
snapshot.data!.docs.map((DocumentSnapshot document){
Map a = document.data() as Map<String, dynamic>;
symptomsList.add(a['name']);
a['id'] = document.id;
}).toList();
return MultiSelectFormField(
autovalidate: AutovalidateMode.disabled,
chipBackGroundColor: Colors.blue[900],
chipLabelStyle: const TextStyle(fontWeight: FontWeight.bold, color: Colors.white),
dialogTextStyle: const TextStyle(fontWeight: FontWeight.bold),
checkBoxActiveColor: Colors.blue[900],
checkBoxCheckColor: Colors.white,
dialogShapeBorder: const RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(12.0))),
title: const Text(
"Symptoms",
style: TextStyle(fontSize:20),
),
validator: (value) {
if (value == null || value.length == 0) {
return 'Please select one or more symptoms';
}
return null;
},
dataSource: [
for (String i in symptomsList) {'value' : i}
],
textField: 'value',
valueField: 'value',
okButtonLabel: 'OK',
cancelButtonLabel: 'CANCEL',
hintWidget: const Text('Please choose one or more symptoms'),
initialValue: _symptoms,
onSaved: (value) {
if (value == null) return;
setState(() {
_symptoms = value;
}
);
},
);
}
),
const SizedBox(height:50,),
Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
ElevatedButton(
onPressed: () async{
if(_formKey.currentState!.validate()){
setState(() {
_type = petType.toString();
_symptomsResult = _symptoms!.toList();
addDiagnose(_type,_symptomsResult);
final documentId = diagnosis.id;
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => DiagnosisPage(documentId: documentId),
)
);
clearText();
}
);
}
},
child: const Text(
'Diagnose',
style: TextStyle(fontSize: 18),
),
style: ElevatedButton.styleFrom(primary: Colors.blue[900]),
),
],
),
],
),
)
],
),
),
),
);
}
}