CODEWITHSUNDEEP
javafirebasegoogle-cloud-firestore
vesii
vesii

Reputation: 3128

How to remove item in list with WriteBatch?

I'm using Firebase Cloud database. I queried a collection and got a list of documents. Each document contains a field cars which contains strings. In case the array contains at least three strings I want to remove the string carPath from this array (not the whole array). Otherwise, it should remove the whole document. I'm using WriteBatch. What I did:

fireDB.document(groupPath).collection("users").whereArrayContains("cars",carPath).get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<QuerySnapshot> task) {
        if (task.isSuccessful() && task.getResult() != null) {
            QuerySnapshot snapshot = task.getResult();
            for (DocumentSnapshot curr : snapshot.getDocuments()) {
                List<String> cars = (List<String>) curr.get("cars");
                if (cars == null) continue;
                if (cars.size() <= 2) {
                    batch.delete(snapshot.getReference());
                } else {
                    // What to do here?
                }
            }
        }
    }
});

How should I remove one item in the list with WriteBatch?

Upvotes: 0

Views: 30

Answers (1)

Doug Stevenson
Doug Stevenson

Reputation: 317467

What you're trying to do is just a document update. You can do a regular update with FieldValue.arrayRemove(). Except you will do it in the context of a batch using update() instead of a standalone update.

batch.update(snapshot.getReference(), "cars", FieldValue.arrayRemove(carPath));

Upvotes: 1

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