MainActivity.java

package ru.agamov.mqttsample;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

import com.pubnub.api.Callback;
import com.pubnub.api.Pubnub;
import com.pubnub.api.PubnubError;
import com.pubnub.api.PubnubException;

public class MainActivity extends AppCompatActivity {
    Pubnub pubnub;

    private static final String TAG = "PubNub";

    WifiReceiver mReceiver;
    IntentFilter mFilter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setupReceiver();
        setupPubNub();
    }

    @Override
    protected void onPause() {
        unregisterReceiver(mReceiver);
        super.onPause();
    }

    @Override
    protected void onResume() {
        super.onResume();
        registerReceiver(mReceiver, mFilter);

    }

    private void setupReceiver() {
        mReceiver = new WifiReceiver();
        mFilter = new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");
    }


    private void setupPubNub() {
        pubnub = new Pubnub("pub-c-19bcd7c5-0d5c-4159-9919-7f79d4944c56", "sub-c-6b78c260-7880-11e5-a49d-02ee2ddab7fe");
//        final Pubnub pubnub = new Pubnub("demo", "demo");

        try {
            pubnub.subscribe("my_channel", new Callback() {
                        @Override
                        public void connectCallback(String channel, Object message) {
                            pubnub.publish("my_channel", "Hello from the PubNub Java SDK", new Callback() {
                            });
                        }

                        @Override
                        public void disconnectCallback(String channel, Object message) {
                            Log.d(TAG, "SUBSCRIBE : DISCONNECT on channel:" + channel
                                    + " : " + message.getClass() + " : "
                                    + message.toString());
                        }

                        public void reconnectCallback(String channel, Object message) {
                            Log.d(TAG, "SUBSCRIBE : RECONNECT on channel:" + channel
                                    + " : " + message.getClass() + " : "
                                    + message.toString());
                        }

                        @Override
                        public void successCallback(String channel, Object message) {
                            Log.d(TAG, "SUBSCRIBE : " + channel + " : "
                                    + message.getClass() + " : " + message.toString());
                        }

                        @Override
                        public void errorCallback(String channel, PubnubError error) {
                            Log.e(TAG, "SUBSCRIBE : ERROR on channel " + channel
                                    + " : " + error.toString());
                        }
                    }
            );
        } catch (PubnubException e) {
            Log.e(TAG, "Exception", e);
            //System.out.println(e.toString());
        }

    }


    public class WifiReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            ConnectivityManager conMan = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo netInfo = conMan.getActiveNetworkInfo();
            if (netInfo != null && netInfo.getType() == ConnectivityManager.TYPE_WIFI)
                Log.d("__WifiReceiver__", "Connected!");
            else
                Log.d("__WifiReceiver__", "Disconnected!!!");
        }
    }

    ;
}