I am trying to make my Flutter app update when a change is made to the usersCollection.document(user.uid) firebase document.
When the user document is updated I want to retrieve the data from this document but also from another firebase document, facilitiesCollection.document(...).
My current code
Future<Map> _getCheckedInFacilityData() async {
Map<String, dynamic> result = {};
try {
DocumentSnapshot userDoc =
await _db.usersCollection.document(user.uid).get();
if (userDoc.data['checkedIn']) {
// User is checked in
DocumentSnapshot facDoc = await _db.facilitiesCollection
.document(userDoc.data['activeFacilityID'].toString())
.get();
result['facilityID'] = userDoc.data['activeFacilityID'];
result['sessionID'] = userDoc.data['activeSessionID'];
result['facilityActiveUsers'] = facDoc.data['activeUsers'].length;
result['facilityName'] = facDoc.data['name'];
return result;
}
} catch (er) {
debugPrint(er.toString());
}
return null;
}
FutureBuilder<Map>(
future: _getCheckedInFacilityData(),
builder: (context, map) {
switch (map.connectionState) {
case ConnectionState.waiting:
return Center(child: CircularProgressIndicator());
...
This is currently working but the page is not updated when a change is made to the user document.
I haven't been using Flutter/Dart for long so any ideas are welcome.
Is it possible to return a custom object/map which is comprised of 2 separate documents from a StreamBuilder, or is there another method that will work in my situation.
Surely you can do it with Streams asyncMap() and then listen in StreamBuilder
Basic algoritm
Get stream of you first data type and then asyncMap to wait second data type and return them both
stream.asyncMap(
(v1) async {
final v2 = await Future.delayed(Duration(seconds: 1), () => 4);
return v1 * v2;
},
);
Closer to your code
Stream<Map<String, dynamic>> _getCheckedInFacilityData() {
return _db.usersCollection.document(user.uid).snapshots()
.asyncMap(
(userDoc) async {
final DocumentSnapshot facDoc =
await _db.facilitiesCollection
.document(userDoc.data['activeFacilityID'].toString())
.get();
final Map<String, dynamic> userMap = userDoc.data;
final Map<String, dynamic> facMap = facDoc.data;
return userMap..addAll(facMap);
},
);
}
In this function I merge two maps - be carefull if both maps have identical keys map will keep only last was added key in our case from addAll(facMap)
Last step is to show you streamed data on screen - use StreamBuilder
StreamBuilder<Map>(
stream: _getCheckedInFacilityData(),
builder: (context, snapshot) {
if (snapshot.hasError) {
return Text('${snapshot.error}');
} else if (snapshot.connectionState == ConnectionState.waiting) {
return LinearProgressIndicator();
}
return /* some widget that shows your data*/;
},
),
Related
Edit: This Question is outdated, and I am sure, new documentation and more recent answers are available as of now.
I want to retrieve data of only a single document via its ID. My approach with example data of:
TESTID1 {
'name': 'example',
'data': 'sample data',
}
was something like this:
Firestore.instance.document('TESTID1').get() => then(function(document) {
print(document('name'));
}
but that does not seem to be correct syntax.
I was not able to find any detailed documentation on querying firestore within flutter (dart) since the firebase documentation only addresses Native WEB, iOS, Android etc. but not Flutter. The documentation of cloud_firestore is also way too short. There is only one example that shows how to query multiple documents into a stream which is not what i want to do.
Related issue on missing documentation:
https://github.com/flutter/flutter/issues/14324
It can't be that hard to get data from a single document.
UPDATE:
Firestore.instance.collection('COLLECTION').document('ID')
.get().then((DocumentSnapshot) =>
print(DocumentSnapshot.data['key'].toString());
);
is not executed.
but that does not seem to be correct syntax.
It is not the correct syntax because you are missing a collection() call. You cannot call document() directly on your Firestore.instance. To solve this, you should use something like this:
var document = await Firestore.instance.collection('COLLECTION_NAME').document('TESTID1');
document.get() => then(function(document) {
print(document("name"));
});
Or in more simpler way:
var document = await Firestore.instance.document('COLLECTION_NAME/TESTID1');
document.get() => then(function(document) {
print(document("name"));
});
If you want to get data in realtime, please use the following code:
Widget build(BuildContext context) {
return new StreamBuilder(
stream: Firestore.instance.collection('COLLECTION_NAME').document('TESTID1').snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new Text("Loading");
}
var userDocument = snapshot.data;
return new Text(userDocument["name"]);
}
);
}
It will help you set also the name to a text view.
Null safe code (Recommended)
You can either query the document in a function (for example on press of a button) or inside a widget (like a FutureBuilder).
In a method: (one time listen)
var collection = FirebaseFirestore.instance.collection('users');
var docSnapshot = await collection.doc('doc_id').get();
if (docSnapshot.exists) {
Map<String, dynamic>? data = docSnapshot.data();
var value = data?['some_field']; // <-- The value you want to retrieve.
// Call setState if needed.
}
In a FutureBuilder (one time listen)
FutureBuilder<DocumentSnapshot<Map<String, dynamic>>>(
future: collection.doc('doc_id').get(),
builder: (_, snapshot) {
if (snapshot.hasError) return Text ('Error = ${snapshot.error}');
if (snapshot.hasData) {
var data = snapshot.data!.data();
var value = data!['some_field']; // <-- Your value
return Text('Value = $value');
}
return Center(child: CircularProgressIndicator());
},
)
In a StreamBuilder: (always listening)
StreamBuilder<DocumentSnapshot<Map<String, dynamic>>>(
stream: collection.doc('doc_id').snapshots(),
builder: (_, snapshot) {
if (snapshot.hasError) return Text('Error = ${snapshot.error}');
if (snapshot.hasData) {
var output = snapshot.data!.data();
var value = output!['some_field']; // <-- Your value
return Text('Value = $value');
}
return Center(child: CircularProgressIndicator());
},
)
If you want to use a where clause
await Firestore.instance.collection('collection_name').where(
FieldPath.documentId,
isEqualTo: "some_id"
).getDocuments().then((event) {
if (event.documents.isNotEmpty) {
Map<String, dynamic> documentData = event.documents.single.data; //if it is a single document
}
}).catchError((e) => print("error fetching data: $e"));
This is simple you can use a DOCUMENT SNAPSHOT
DocumentSnapshot variable = await Firestore.instance.collection('COLLECTION NAME').document('DOCUMENT ID').get();
You can access its data using variable.data['FEILD_NAME']
Update FirebaseFirestore 12/2021
StreamBuilder(
stream: FirebaseFirestore.instance
.collection('YOUR COLLECTION NAME')
.doc(id) //ID OF DOCUMENT
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new CircularProgressIndicator();
}
var document = snapshot.data;
return new Text(document["name"]);
}
);
}
This is what worked for me in 2021
var userPhotos;
Future<void> getPhoto(id) async {
//query the user photo
await FirebaseFirestore.instance.collection("users").doc(id).snapshots().listen((event) {
setState(() {
userPhotos = event.get("photoUrl");
print(userPhotos);
});
});
}
Use this code when you just want to fetch a document from firestore collection , to perform some operations on it, and not to display it using some widget (updated jan 2022 )
fetchDoc() async {
// enter here the path , from where you want to fetch the doc
DocumentSnapshot pathData = await FirebaseFirestore.instance
.collection('ProfileData')
.doc(currentUser.uid)
.get();
if (pathData.exists) {
Map<String, dynamic>? fetchDoc = pathData.data() as Map<String, dynamic>?;
//Now use fetchDoc?['KEY_names'], to access the data from firestore, to perform operations , for eg
controllerName.text = fetchDoc?['userName']
// setState(() {}); // use only if needed
}
}
Simple way :
StreamBuilder(
stream: FirebaseFirestore.instance
.collection('YOUR COLLECTION NAME')
.doc(id) //ID OF DOCUMENT
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new CircularProgressIndicator();
}
var document = snapshot.data;
return new Text(document["name"]);
}
);
}
var document = await FirebaseFirestore.instance.collection('Users').doc('CXvGTxT49NUoKi9gRt96ltvljz42').get();
Map<String,dynamic>? value = document.data();
print(value!['userId']);
You can get the Firestore document by following code:
future FirebaseDocument() async{
var variable = await FirebaseFirestore.instance.collection('Collection_name').doc('Document_Id').get();
print(variable['field_name']);
}
Use this simple code:
Firestore.instance.collection("users").document().setData({
"name":"Majeed Ahmed"
});
I have a collection in Firestore. It has a field array i am trying to get the array from Firestore and assign it to a list in flutter.
My collection is as below
My code for getting data from Firestore
List<Offset> pointlist = <Offset>[];
getdata() async{
await Firestore.instance.collection("points").document('biZV7cepFJA8T6FTcF08').get().then((value){
setState(() {
List<Offset> pointlist = List.from(value.data['point']);
});
});
}
#override
void initState() {
super.initState();
getdata();
}
i get this error type 'String' is not a subtype of type 'Offset'
The thing which you are doing wrong is this:
// You have initialised your List as a Offset Object Type
List<Offset> pointList;
Secondly, the data you are assigning is a String, if you closely take a look at that firebase.
"Offset(x,y)"
Finally, trying to assign the String value to a List of type Offset class/object
If you want to make the thing works, then either make the List of type String and then add it to the List
List<String> pointlist = List.from(value.data['point']);
Or first Add the data to the Offset Object like this, and then pass it to the List
List<Offset> pointList = <Offset>[];
getdata() async{
await Firestore.instance.collection("points").document('biZV7cepFJA8T6FTcF08').get().then((value){
setState(() {
// first add the data to the Offset object
List.from(value.data['point']).forEach((element){
Offset data = new Offset(element);
//then add the data to the List<Offset>, now we have a type Offset
pointList.add(data);
});
});
});
}
SUMMARY
Always look for the data type you are giving to the List, if you are trying to add the data which is not a type T of List<T>, you will always get this error of type mismatch. Hope this will give you some clarity and some basic idea about programming. Keep learning :)
you have to declare list and all list item will be store in declared list so you can access it.
List<dynamic> alldata =[];
Future<QuerySnapshot?> getData() async {
dataofItem = FirebaseFirestore.instance
.collection('$data')
.get()
.then((QuerySnapshot? querySnapshot) {
querySnapshot!.docs.forEach((doc) {
allData = doc["item_text_"];
print("allData = $allData");
// print("getData = ${doc["item_text_"]}");
});
});
return dataofItem;
}
Lets assume the structure to be.
...
arrayOfString
|_element1
|_element2
|_element3
...
Use the following code to get the array elements of arrayOfString parameter
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: StreamBuilder<DocumentSnapshot<Map<String, dynamic>>>(
stream: FirebaseFirestore.instance
.collection('users')
.doc(FirebaseAuth.instance.currentUser!.uid)
.snapshots(),
builder:
(BuildContext context, AsyncSnapshot<DocumentSnapshot> snapshot) {
if (snapshot.hasError) {
return const Text('Something went wrong');
}
if (snapshot.connectionState == ConnectionState.waiting) {
return const Text("Loading");
}
Map<String, dynamic> data =
snapshot.data!.data()! as Map<String, dynamic>;
return ListView(
children: data['arrayOfString'].map<Widget>((e) { 👈 arrayOfString has array of Strings
return ListTile(
title: Text(e.toString()), // 👈 printing every string
);
}).toList());
},
),
),
);
}
I want to fetch data from firestore and use that to build cards in Flutter using ListView on the homepage. While using the navigation menu to switch between screens, I intend to reuse the data once fetched in a session rather than fetching it from the database every time I return to the homepage. But, this is not happening; The data is fetched from the database every time I go to the homepage.
FutureBuilder(
future: databaseService(),
builder: (context, snapshot) {
if (snapshot.hasData) {
stringMap = snapshot.data;
}
return ListView.builder(
itemBuilder: (context, index) {
stringMap.forEach((index, value) => {
print("The stringMap is ${stringMap.keys.toList()}"),
});
return HomepageCards(
user: widget.user,
cardDetails: stringMap[stringMap.keys.toList()[index]],
);
},
itemCount: stringMap.length,
scrollDirection: Axis.vertical,
controller: _controller,
shrinkWrap: true,
);
},
)
databaseService() async {
return DatabaseService().streamHomePage(widget.user);
}
DatabaseService.dart
class DatabaseService {
final Firestore _db = Firestore.instance;
HomePage home = new HomePage();
Map homePageMap = new Map<String, Map<String, dynamic>>();
/// Query a subcollection
Future streamHomePage(FirebaseUser user) async {
// Initialise the model map
home.homeModel = <String, dynamic>{};
home.homeModel['driverDetails'] = new Map();
var ref = _db
.collection('homepage')
.document(user.uid)
.collection('h')
.document('28032020');
// TODO: Try to use cached data. Also try to find the pattern for switching between server and cache
await ref.get(source: Source.serverAndCache).then((ref) => {
ref.data.forEach((index, value) => {
home.homeModel = value,
homePageMap[index] = value,
}),
});
return homePageMap;
}
}
Any leads to make the data once fetched reusable would be highly appreciated.
Since you only want to fetch it once and then fetch it from the session, therefore you can just check if the session contains the data or not. Another way is to use shared_preferences, for example:
SharedPreferences prefs = await SharedPreferences.getInstance();
databaseService() async {
await prefs.setBool('retrieved', true);
return DatabaseService().streamHomePage(widget.user);
}
Then before executing the FutureBuilder check if retrieved is equal to true using getBool() and retrieve data from the session
The idea is to display a string from a random document within a collection in Firebase. A simple function getRandom() retrieves the total number of documents and generates a random integer r that is fed into the Firebase instance.
The output in the app is always null.
StreamBuilder(
initialData: Words(),
stream: getWords(),
builder: (context, snapshot){
if(!snapshot.hasData){
return Center(child: Text("NO DATA"));
}else {
var r = snapshot.data;
return Center(child: Text("${r.english}"));
}
})
Stream<Words> getWords() async* {
int r = await getRandom();
print("RANDOM NO: " + "$r");
Firestore.instance.document("vocabs/foods/words/$r")
.get()
.then((snapshot){
try {
return Words().english;
} catch(e){
print("ERROR");
return null;
}
});
}
class Words{
Words(): super();
String english;
Words.fromSnapshot(DocumentSnapshot snapshot)
: english = snapshot.data["english"];
}
I've constructed a this piece of sample code for you to give you some options to achieve what you'd like to do:
import 'dart:async';
class Word {
final String english;
const Word(this.english);
}
Future<Iterable<Word>> get firebaseSnapshot async => [ Word('aWord'), Word('bWord'), Word('cWord') ];
Stream<String> getEnglishWords() async* {
yield* await firebaseSnapshot.then((words) => Stream.fromIterable(words.map((w) => w.english)));
}
Stream<String> getEnglishWords2() async* {
final words = await firebaseSnapshot.then((words) => words.map((w) => w.english));
yield* Stream.fromIterable(words);
}
Stream<String> getEnglishWords3() async* {
final snapshot = await firebaseSnapshot;
for(final word in snapshot) {
yield word.english;
}
}
main() async {
await for(final englishWord in getEnglishWords()) {
print(englishWord);
}
await for(final englishWord in getEnglishWords2()) {
print(englishWord);
}
await for(final englishWord in getEnglishWords3()) {
print(englishWord);
}
}
Option No. 2 is the one I'd use. There is some significant performance consideration around it. I am scraping the back of my mind for the lecture around it... Nope, can't recall... If I find it, I'll update ya.
Edit: This Question is outdated, and I am sure, new documentation and more recent answers are available as of now.
I want to retrieve data of only a single document via its ID. My approach with example data of:
TESTID1 {
'name': 'example',
'data': 'sample data',
}
was something like this:
Firestore.instance.document('TESTID1').get() => then(function(document) {
print(document('name'));
}
but that does not seem to be correct syntax.
I was not able to find any detailed documentation on querying firestore within flutter (dart) since the firebase documentation only addresses Native WEB, iOS, Android etc. but not Flutter. The documentation of cloud_firestore is also way too short. There is only one example that shows how to query multiple documents into a stream which is not what i want to do.
Related issue on missing documentation:
https://github.com/flutter/flutter/issues/14324
It can't be that hard to get data from a single document.
UPDATE:
Firestore.instance.collection('COLLECTION').document('ID')
.get().then((DocumentSnapshot) =>
print(DocumentSnapshot.data['key'].toString());
);
is not executed.
but that does not seem to be correct syntax.
It is not the correct syntax because you are missing a collection() call. You cannot call document() directly on your Firestore.instance. To solve this, you should use something like this:
var document = await Firestore.instance.collection('COLLECTION_NAME').document('TESTID1');
document.get() => then(function(document) {
print(document("name"));
});
Or in more simpler way:
var document = await Firestore.instance.document('COLLECTION_NAME/TESTID1');
document.get() => then(function(document) {
print(document("name"));
});
If you want to get data in realtime, please use the following code:
Widget build(BuildContext context) {
return new StreamBuilder(
stream: Firestore.instance.collection('COLLECTION_NAME').document('TESTID1').snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new Text("Loading");
}
var userDocument = snapshot.data;
return new Text(userDocument["name"]);
}
);
}
It will help you set also the name to a text view.
Null safe code (Recommended)
You can either query the document in a function (for example on press of a button) or inside a widget (like a FutureBuilder).
In a method: (one time listen)
var collection = FirebaseFirestore.instance.collection('users');
var docSnapshot = await collection.doc('doc_id').get();
if (docSnapshot.exists) {
Map<String, dynamic>? data = docSnapshot.data();
var value = data?['some_field']; // <-- The value you want to retrieve.
// Call setState if needed.
}
In a FutureBuilder (one time listen)
FutureBuilder<DocumentSnapshot<Map<String, dynamic>>>(
future: collection.doc('doc_id').get(),
builder: (_, snapshot) {
if (snapshot.hasError) return Text ('Error = ${snapshot.error}');
if (snapshot.hasData) {
var data = snapshot.data!.data();
var value = data!['some_field']; // <-- Your value
return Text('Value = $value');
}
return Center(child: CircularProgressIndicator());
},
)
In a StreamBuilder: (always listening)
StreamBuilder<DocumentSnapshot<Map<String, dynamic>>>(
stream: collection.doc('doc_id').snapshots(),
builder: (_, snapshot) {
if (snapshot.hasError) return Text('Error = ${snapshot.error}');
if (snapshot.hasData) {
var output = snapshot.data!.data();
var value = output!['some_field']; // <-- Your value
return Text('Value = $value');
}
return Center(child: CircularProgressIndicator());
},
)
If you want to use a where clause
await Firestore.instance.collection('collection_name').where(
FieldPath.documentId,
isEqualTo: "some_id"
).getDocuments().then((event) {
if (event.documents.isNotEmpty) {
Map<String, dynamic> documentData = event.documents.single.data; //if it is a single document
}
}).catchError((e) => print("error fetching data: $e"));
This is simple you can use a DOCUMENT SNAPSHOT
DocumentSnapshot variable = await Firestore.instance.collection('COLLECTION NAME').document('DOCUMENT ID').get();
You can access its data using variable.data['FEILD_NAME']
Update FirebaseFirestore 12/2021
StreamBuilder(
stream: FirebaseFirestore.instance
.collection('YOUR COLLECTION NAME')
.doc(id) //ID OF DOCUMENT
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new CircularProgressIndicator();
}
var document = snapshot.data;
return new Text(document["name"]);
}
);
}
This is what worked for me in 2021
var userPhotos;
Future<void> getPhoto(id) async {
//query the user photo
await FirebaseFirestore.instance.collection("users").doc(id).snapshots().listen((event) {
setState(() {
userPhotos = event.get("photoUrl");
print(userPhotos);
});
});
}
Use this code when you just want to fetch a document from firestore collection , to perform some operations on it, and not to display it using some widget (updated jan 2022 )
fetchDoc() async {
// enter here the path , from where you want to fetch the doc
DocumentSnapshot pathData = await FirebaseFirestore.instance
.collection('ProfileData')
.doc(currentUser.uid)
.get();
if (pathData.exists) {
Map<String, dynamic>? fetchDoc = pathData.data() as Map<String, dynamic>?;
//Now use fetchDoc?['KEY_names'], to access the data from firestore, to perform operations , for eg
controllerName.text = fetchDoc?['userName']
// setState(() {}); // use only if needed
}
}
Simple way :
StreamBuilder(
stream: FirebaseFirestore.instance
.collection('YOUR COLLECTION NAME')
.doc(id) //ID OF DOCUMENT
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return new CircularProgressIndicator();
}
var document = snapshot.data;
return new Text(document["name"]);
}
);
}
var document = await FirebaseFirestore.instance.collection('Users').doc('CXvGTxT49NUoKi9gRt96ltvljz42').get();
Map<String,dynamic>? value = document.data();
print(value!['userId']);
You can get the Firestore document by following code:
future FirebaseDocument() async{
var variable = await FirebaseFirestore.instance.collection('Collection_name').doc('Document_Id').get();
print(variable['field_name']);
}
Use this simple code:
Firestore.instance.collection("users").document().setData({
"name":"Majeed Ahmed"
});