firebaseArray descending order?

Question

Using firebaseArray, is it possible to order by a specified child key: (https://www.firebase.com/docs/web/guide/retrieving-data.html#section-queries)?

var fi         


        

Answer 1

Here is how you can order by date. Just use queryOrderedByChild(dateKey) and it will be in asc order, to make desc you can do array.reverse()

POST_REF.queryOrderedByChild(PostKeys.kPostDate).observeEventType(.Value, withBlock: {
  snapshot in

  var localPosts = [Post]()
    for item in snapshot.children {
      let postItem = Post(snapshot: item as! FDataSnapshot)
      localPosts.append(postItem)
    }
  //Display at desc order
   let reverseResults = localPosts.reverse() as [Post]
       completion(postsArray: reverseResults)
    }, withCancelBlock: { error in
   completion(postsArray: nil)
})

Answer 2

This doesn't directly answer the original question, but for anyone using FirebaseUI Java/Android, with a RecyclerView, it's possible to order the RecyclerView in reverse, rather than using a query on Firebase:

Example:

LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
layoutManager.setReverseLayout(true);
layoutManager.setStackFromEnd(true);
recyclerView.setLayoutManager(layoutManager)

(Ensuring you set both before adding the layout manager to the RecyclerView also)

Github issue: https://github.com/firebase/FirebaseUI-Android/issues/90#issuecomment-230643303