CODEWITHSUNDEEP
firebasedartfluttergoogle-cloud-firestorequerying
blandaadrian
blandaadrian

Reputation: 752

Query a single document from Firestore in Flutter (cloud_firestore Plugin)

Edit: This Question is outdated, and I am sure, new documentation and more recent answers are available as of now.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.

Upvotes: 61

Views: 135282

Answers (11)

Alex Mamo
Alex Mamo

Reputation: 138824

but that does not seem to be the correct syntax.

It is not the correct syntax because you are missing a collection() call. 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.

Upvotes: 91

Umesh Rajput
Umesh Rajput

Reputation: 214

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']); 
}

Upvotes: 1

avill blbn
avill blbn

Reputation: 121

        var  document = await FirebaseFirestore.instance.collection('Users').doc('CXvGTxT49NUoKi9gRt96ltvljz42').get();
        Map<String,dynamic>? value = document.data();
        print(value!['userId']);

Upvotes: 1

Woah
Woah

Reputation: 31

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
   }
}

Upvotes: 3

Majeed Ahmed
Majeed Ahmed

Reputation: 9

Use this simple code:

Firestore.instance.collection("users").document().setData({
   "name":"Majeed Ahmed"
});

Upvotes: -3

CopsOnRoad
CopsOnRoad

Reputation: 267574

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());
  },
)

Upvotes: 43

Koffi Innocent Konan
Koffi Innocent Konan

Reputation: 11

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"]);
     }
  );
}

Upvotes: 1

jo3ght
jo3ght

Reputation: 129

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"]);
     }
  );
}

Upvotes: 7

Ronny K
Ronny K

Reputation: 3741

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);
          });
        });
      }

Upvotes: 3

thilinaj
thilinaj

Reputation: 379

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"));

Upvotes: 27

SWAG Assassin YT
SWAG Assassin YT

Reputation: 295

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']

Upvotes: 13

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