android - Offline sort of FirebaseRecyclerAdapter -

i'm using firebaserecycleradapter retrieve data firebase database, , i've pretty worked out how retrieve data in order desire.

to avoid duplication , ease database maintenance, i'd add key database entry allows me return queries based on key. storing data twice. once see, , once if user had joined group (under groupname).

to return query based on group, original search follows:

databasereference.child(groupname).child("exerciseid"+mexerciseid).orderbychild(sortorder).limittofirst(100); 

but believe duplication can avoided adding key "group" post. (it make maintenance easier users switch groups).

the "group" database query has become:

databasereference.child("exerciseid"+mexerciseid).orderbychild("group").equalto(groupname); 

all good, except data no longer sorted per "sortorder". firebase not allow multiple sort criteria, believe solution lies in offline sorting.

so, how 1 sort adapter offline?

my adapter pretty standard:

madapter = new firebaserecycleradapter<post, postviewholder>(post.class, r.layout.item_post, postviewholder.class, dataquery)  {      @override     protected void populateviewholder(final postviewholder viewholder, final post model, final int position)     {          final databasereference postref = getref(position);          // bind post viewholder, setting onclicklistener star button         viewholder.bindtopost(model, position, postref.getkey(), null);      }      mrecycler.setadapter(madapter); } 

i've implemented comparable in post, problem data stored can pass collections.sort() in sort of way:

private list<post> mposts = new arraylist<>(); mposts.add(model);  collections.sort(mposts, post.comparators.alltime); 

the adapters in firebaseui library display data in order returned underlying firebasedatabase reference or query.

you file feature request on github repo (since i'm not sure covered in this one yet). alternatively fork library , roll own implementation of functionality.