public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_msg_main);

    Intent in = getIntent();

    username = in.getStringExtra("username");
    password = in.getStringExtra("password");
    nickname = in.getStringExtra("nickname");

    messages = new ArrayList<Message>();
    txtNewMsg = (EditText) this.findViewById(R.id.text);
    adapter = new MessagesAdapter(this, messages);
    setListAdapter(adapter);

    registerReceiver(mHandleMessageReceiver, new IntentFilter(DISPLAY_MESSAGE_ACTION));
}

private final BroadcastReceiver mHandleMessageReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String newMessage = intent.getExtras().getString(EXTRA_MESSAGE);
        // Waking up mobile if it is sleeping
        WakeLocker.acquire(getApplicationContext());

        SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
        String currentDateandTime = sdf.format(new Date());

        Spanned newMessageDate = Html.fromHtml("<small><i><font color="red">" + currentDateandTime + "</font></i></small>" + " " + "<small><i><font color="blue">" + nickname + "</font></i></small>" + "<br />" + newMessage);

        addNewMessage(new Message(newMessageDate, true));

        WakeLocker.release();
    }
};

@Override
protected void onDestroy() {
    if (mRegisterTask != null) {
        mRegisterTask.cancel(true);
    }
    try {
        unregisterReceiver(mHandleMessageReceiver);
        GCMRegistrar.onDestroy(this);
    } catch (Exception e) {
        Log.e("UnRegister Receiver Error", "> " + e.getMessage());
    }
    super.onDestroy();
}

void addNewMessage(Message m)
{
    messages.add(m);
    adapter.notifyDataSetChanged();
    getListView().setSelection(messages.size()-1);
}