Firestore delete all objects in collection

Question

How can i delete all the objects in my collection? I am trying to figure out how to do this in Java. batch.delete requires a DocumentReference, but can't figure out how to get it.

Answer 1

WriteBatch batch = db.batch();

db.collection("myobjs")
    .get()
    .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            if (task.isSuccessful()) {
                for (QueryDocumentSnapshot document : task.getResult()) {
                    batch.delete(document.getReference());
                    Log.d(TAG, document.getId() + " delete => " + document.getData());
                }

            } else {
                Log.w(TAG, "Error getting documents.", task.getException());
            }

            batch.commit().addOnCompleteListener(new OnCompleteListener<Void>() {
                @Override
                public void onComplete(@NonNull Task<Void> task) {
                    Log.w(TAG, "Batch completed.", task.getException());
                }
            });
        }