Updating a string field in all documents found in a collection in Firestore

Question

Basically, I would like to know if it is possible to update all of the documents found in a collection in Firestore. I am able to get all the documents in a list like so:

<

Answer 1

In order to update all the documents in a collection first you have have to retrieve all of them in a List and then iterate that list and update them. Here is a sample code:-

for (int k = 0; k < list.size(); k++) {
    firestore.collection("Events").document(list.get(k))
        .update("Key", value).addOnSuccessListener(new OnSuccessListener()
            {
                @Override
                public void onSuccess(Void aVoid) {
                    Log.i("Update", "Value Updated");

                }
             })
             .addOnFailureListener(new OnFailureListener() {
                 @Override
                 public void onFailure(Exception e) {
                     Toast.makeText(MainActivity.this, "Error In Updating Details: " + e.getMessage(), Toast.LENGTH_SHORT).show();
                 }
    });
}