How to Update fields using where conditions Current user = Key ( User ID) firestore and flutter - flutter

Question

Hello I'm using flutter and firebase so I have firestore I have on collocation name Institutes and in document has names of Institutes and my Fields I have profile data ….no I need update some fields by where conditions where currant user = Key User id in the fields*
Screenshot
onPressed: ()async {
final FirebaseAuth auth = FirebaseAuth.instance;
final user = await auth.currentUser();
final iduser = user.uid;
final emailuser = user.email;
final snapshot = await Firestore.instance.collection("Institute")
.document(_Institute_name.text).get();
if (snapshot.exists) {
print(this name is existd);
} else {
await DataBaseService(email: emailuser,
uid: iduser,
Document: _Institute_name.text)
.CreateCollectionInofwithImage(
_Institute_name.text, Institute_address.text,
int.parse(Institute_phone.text), _image).then((isdone) {
setState(() {
Institute_address.clear();
Institute_phone.clear();
_Institute_name.clear();
_image = null;
});
});
}
}

Answer 1

Okay try this
onPressed: ()async {
final FirebaseAuth auth = FirebaseAuth.instance;
final user = await auth.currentUser();
final iduser = user.uid;
final emailuser = user.email;
QuerySnapshot snapshot = await Firestore.instance
.collection('Institute')
.where('user id', isEqualTo: iduser)//I think this is your field name from the
//picture it looks like theres a space in it
.getDocuments();
if (snapshot != null) {
Map<String,dynamic> document = snapshot.documents[0].data;
//Then you would reference this by document['fieldName']
} else {
await DataBaseService(email: emailuser,
uid: iduser,
Document: _Institute_name.text)
.CreateCollectionInofwithImage(
_Institute_name.text, Institute_address.text,
int.parse(Institute_phone.text), _image).then((isdone) {
setState(() {
Institute_address.clear();
Institute_phone.clear();
_Institute_name.clear();
_image = null;
});
});
}
}