Pobieranie adresow urzadzen

mListMAC = new HashMap<>();
        mRef.child("DEVICES").addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                if(dataSnapshot.getKey().equals("DEVICES")){
                    int i=1;
                    for(DataSnapshot snapshot: dataSnapshot.getChildren()){

                        tempNameDevice.add(snapshot.getKey().toString());
                        Log.d(TAG,snapshot.getKey() + ": "+ snapshot.getValue());

                        final int tempPosition = i;

                        mDevicesRef.child("DEVICES").child("MAC"+i).child("address").addValueEventListener(new ValueEventListener() {
                            @Override
                            public void onDataChange(DataSnapshot dataSnapshot) {
                                String data = dataSnapshot.getValue(String.class);
//

                                if(!mListMAC.containsKey(tempNameDevice.get(tempPosition-1))){
                                    mListMAC.put(tempNameDevice.get(tempPosition-1),data);
                                }

//                                MACAdresses.add(data);

                                Log.d(TAG,dataSnapshot.getKey() + ": "+ dataSnapshot.getValue());
                                Iterator iteratorMAC = mListMAC.keySet().iterator();
                                while(iteratorMAC.hasNext()) {
                                    String key=(String)iteratorMAC.next();
                                    String value = (String) mListMAC.get(key);

                                    MACAdresses.add(key +": "+value);
                                    iteratorMAC.remove();
//                                    Toast.makeText(getContext(),"Key: "+key+" Value: "+value, Toast.LENGTH_LONG).show();
                                }
                                spinnerDevices.setAdapter(new ArrayAdapter<String>(getContext(),android.R.layout.simple_spinner_dropdown_item,MACAdresses));

                            }

                            @Override
                            public void onCancelled(DatabaseError databaseError) {

                            }
                        });
                        i++;

                    }


                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });