我如何检索/获取Firebase的值

Question

这是我在Android上的代码（不起作用） - ＆gt;错误 -

com.firebase.client.FirebaseException: Failed to bounce to type at 
com.firebase.client.DataSnapshot.getValue(DataSnapshot.java:183) at 
ua.deti.cm.pt.livingcity.MainFragment$1.onDataChange(MainFragment.java:83) at 
com.firebase.client.core.ValueEventRegistration.fireEvent(ValueEventRegistration.java:45)

---- code ----

Firebase.setAndroidContext(getActivity().getApplicationContext());
        Firebase mRef;
        mRef = new Firebase("https://livingcityapp.firebaseio.com");
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        String currentDateandTime = sdf.format(new Date());
        Firebase usersRef = mRef.child(currentDateandTime);
        HashMap<String, Object> mapaCompleto = new HashMap<>();
        usersRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                Log.i("There are", dataSnapshot.getChildrenCount() + "dados");
                for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
                    FireBaseDataClass post = postSnapshot.getValue(FireBaseDataClass.class);
                    Log.i("o que é isto?", post.getHora()+ " - " + post.getTemperature()+ " - " + post.getHumidade());
                }
            }

            @Override
            public void onCancelled(FirebaseError firebaseError) {
                Log.i("The read has failed", firebaseError.getMessage());
            }
        });

---link to Firebase -> https://livingcityapp.firebaseio.com/