private void fetchMessages() {
    rootRef.child("Messages").child(MessageSenderId).child(MessageRecieverId).addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {
            ListView listView = (ListView) findViewById(R.id.messageList);
            ArrayAdapter<String> adapter;
            adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, android.R.id.text1, messagesList);
            String message = dataSnapshot.getValue().toString();
            message = dataSnapshot.child("message").getValue().toString();
//                Log.d("TAG",message );
            messagesList.add(message);
            adapter.notifyDataSetChanged();
            listView.setAdapter(adapter);
        }

        @Override
        public void onChildChanged(DataSnapshot dataSnapshot, String s) {

        }

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {

        }

        @Override
        public void onChildMoved(DataSnapshot dataSnapshot, String s) {

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

}