I am facing a problem with Flutter and Firebase Firestore. I want to take one of the current User's label, and save it as a string. I have already figured out how to find the currentUserID, so that isn't the problem. I just can't figure out how to target the "preference" label in my database. Here is my code for trying to declare it as a string:
String _checkPreference(DocumentSnapshot document) {
Firestore.instance.collection(currentUserId).document('preference').toString();
return _checkPreference(document);
}
The goal is then later to be able to do something like this:
return Text(_checkPreference(document));
Bit I am not really sure what to pass in, and if my method to get it is even correct. Thanks for reading, any help is appreciated!
Related
Talking about querying on Firestore, I found collection().where() function.
It would be a great help, if I could get some good information about the syntax of how does this .where() function works.
Found something like this in a tutorial.
const userExist = db.collection('data').where('users', 'array-contains', user.email);
How does the code above work?
Help would be appreciated.
The query in your question will return all documents that exist in the data collection, where the array property called users contains an email that is equal with what user.email returns.
I have a collection of users and in each document, I want only to get on data which is the array, is there any possible way to only get on, or do I need the whole document?
Try this please. Because its a field, as far as I know, we need to get the whole document first. Hope its help you.
await Firestore.instance.collection('users').document(your document id)
.get().then((Snapshot snapshot){
print(snapshot.data['userCart'])
});
I'm working with Flutter and Firebase (Real-time database). There is some data stored in the db and I want to compare the email (child) of the parent and only want to display the parents containing that particular email. Currently, it is fetching all rows. I think fetching through key value pair would do the work. But I dont know the syntax and unable to find help regarding it. Please help me out.
void myfunc() {
databaseReference.once().then((DataSnapshot snapshot) {
print('Data : ${snapshot.value}');
});
}
try with
yourRef.orderByChild("email").equalTo('abs#abc.com');
Read Query Data
I have been trying to get arrays working in Firebase, and I am aware that there are a lot of references and discussions about this online, and I have read through all of these and none of it works.
First off, the Firebase side. The structure containing the array and two example strings inside it:
Firebase Structure
collection -> document -> fields
userData profileImages URLs (array)
: https://firebasestorage.googleapis.com/v0/b/app-138804.appspot.com/o/jRwscYWLs1DySLMz7jn5Yo2%2Fprofile%2Fimage_picker4459623138678.jpg?alt=media&token=ec1043b-0120-be3c-8e142417
: https://firebasestorage.googleapis.com/v0/b/app-138804.appspot.com/o/jRwscYWLs3872yhdjn5Yo2%2Fprofile%2Fimage_picker445929873mfd38678.jpg?alt=media&token=ec3213b-0120-be9c-8e112632
The first issue I am facing is writing to this array in the database:
Firestore.instance.collection('userData').document('profileImages').updateData({
'URLs': _uploadedFileURL,
});
Whenever I add data to this array, it just overwrites the existing data. I need to be able to keep all the existing data intact and simply add the current new line to the array.
Once this is working, I then need to be able to return all of the strings in this array without needing to know how many of them there will be.
For this part, I basically have nothing at this point. I could show some of the things I have tried based on suggestions from other articles on this, but none of it is even close to working correctly.
im assuming that _uploadedFileURL is a String, and you are updating the property URLs, that's why your data gets overwritten, because you are changing the URLs value to a single string which is _uploadedFileURL. to solve this issue, simply get the current data inside profileImages before commiting the update. like so
final DocumentSnapshot currentData = await Firestore.instance.collection('userData').document('profileImages').get();
Firestore.instance.collection('userData').document('profileImages').updateData({
'URLs': [
...currentData.data['URLs'],
_uploadedFileURL
],
});
and for the second part of your question, all you need is to query for the profileImages
Future<List<String>> _getProfileImages() {
final document = Firestore.instance.collection('userData').document('profileImages').get();
return document.data['profileImages]
}
the result of the get method will be a DocumentSnapshot, and inside the data property will access the profileImages which is a List<String>.
Ok guys and girls I have worked this out. Part 1: appending data to an array in Firebase.
Firestore.instance.collection('userData').document('profileImages').updateDataupdateData({
'URLs':FieldValue.arrayUnion([_uploadedFileURL]),
});
Where _uploadedFileURL is basically a string, for these purposes. Now I have read that arrayUnion, which is super groovy, is only available in Cloud Firestore, and not the Realtime Database. I use Cloud Firestore so it works for me but if you are having issues this might be why.
Now what is extra groovy about Cloud Firestore is that you can similarly remove an element from the array using:
Firestore.instance.collection('userData').document('profileImages').updateDataupdateData({
'URLs':FieldValue.arrayRemove([_uploadedFileURL]),
});
So how to get this data back out again. A simple way I have found to get that data and chuck it into a local array is like so:
List imageURLlist = [];
DocumentReference document = Firestore.instance.collection('userData').document('profileImages');
DocumentSnapshot snapshot = await document.get();
setState(() {
imageURLlist = snapshot.data['URLs'];
});
From here at least you have the data, can add to it, can remove from it and this can be a platform for you to figure out what you want to do with it.
I'm currently creating a dashboard application for my main application, this dashboard is able to display in charts the demography of the users that uses the app. I use Firebase Database as the backend. The JSON tree of my DB is as shown below. My question is, how do I get the amount of data with a specific value of a key? Example: the number of children with the value 'Pria' for the key 'jk' is 2.
My Backend JSON Tree:
So far, I'm able to get all of the data using:
DatabaseReference itemRef = FirebaseDatabase.instance.reference().child('data_pengguna');
And I've also tried the codes below, but it doesn't seem to work:
int jmlPria;
FirebaseDatabase.instance
.reference()
.child('data_pengguna')
.orderByChild('jk')
.equalTo('Pria')
.once()
.then((onValue) {
Map data = onValue.value;
jmlPria = data.length;
});
But I haven't successfully filtered the data and put it inside a variable, can anyone help me?
Many thanks in advance.
That last snippet looks correct, jmlPria should have the number of children.
But the value of jmlPria will only be set to the latest value inside the then() callback. Make sure that Text($jmlPria) is inside the then() callback. Outside of that, jmlPria will not have the correct value.
Also see Doug's great blog post on asynchronous programming.