ConnectionLiveData.java

package test;

import android.arch.lifecycle.LiveData;
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 static test.InternetDetectionActivity.MobileData;
import static test.InternetDetectionActivity.WifiData;

/**
 * Created by Saurabh(aqua) in 2017.
 */

public class ConnectionLiveData extends LiveData<ConnectionModel> {

    private Context context;

    public ConnectionLiveData(Context context) {
        this.context = context;
    }

    @Override
    protected void onActive() {
        super.onActive();
        IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
        context.registerReceiver(networkReceiver, filter);
    }

    @Override
    protected void onInactive() {
        super.onInactive();
        context.unregisterReceiver(networkReceiver);
    }

    private BroadcastReceiver networkReceiver = new BroadcastReceiver() {
        @SuppressWarnings("deprecation")
        @Override
        public void onReceive(Context context, Intent intent) {
            if(intent.getExtras()!=null) {
                NetworkInfo activeNetwork = (NetworkInfo) intent.getExtras().get(ConnectivityManager.EXTRA_NETWORK_INFO);
                boolean isConnected = activeNetwork != null &&
                        activeNetwork.isConnectedOrConnecting();
                if(isConnected) {
                    switch (activeNetwork.getType()){
                        case ConnectivityManager.TYPE_WIFI:
                            postValue(new ConnectionModel(WifiData,true));
                            break;
                        case ConnectivityManager.TYPE_MOBILE:
                            postValue(new ConnectionModel(MobileData,true));
                            break;
                    }
                } else {
                    postValue(new ConnectionModel(0,false));
                }
            }
        }
    };
}

InternetDetectionActivity.java

package test;

import android.arch.lifecycle.LifecycleRegistry;
import android.arch.lifecycle.LifecycleRegistryOwner;
import android.arch.lifecycle.Observer;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;

/**
 * Created by Saurabh(aqua) in 2017.
 */

public class InternetDetectionActivity extends AppCompatActivity implements LifecycleRegistryOwner {

    public static final int MobileData = 2;
    public static final int WifiData = 1;

    private LifecycleRegistry lifecycleRegistry = new LifecycleRegistry(this);

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        /* Live data object and setting an oberser on it */
        ConnectionLiveData connectionLiveData = new ConnectionLiveData(getApplicationContext());
        connectionLiveData.observe(this, new Observer<ConnectionModel>() {
            @Override
            public void onChanged(@Nullable ConnectionModel connection) {
                /* every time connection state changes, we'll be notified and can perform action accordingly */
                if (connection.getIsConnected()) {
                  switch (connection.getType()) {
                    case WifiData:
                        Toast.makeText(this, String.format("Wifi turned ON"), Toast.LENGTH_SHORT).show();
                        break;
                    case MobileData:
                        Toast.makeText(this, String.format("Mobile data turned ON"), Toast.LENGTH_SHORT).show();
                        break;
                   }
                } else {
                    Toast.makeText(this, String.format("Connection turned OFF"), Toast.LENGTH_SHORT).show();
                }
            }
        });
    }

    /* required to make activity life cycle owner */
    @Override
    public LifecycleRegistry getLifecycle() {
        return lifecycleRegistry;
    }
}

Kotlin Code for observing:

val connectionLiveData = ConnectionLiveData(applicationContext)
       connectionLiveData.observe(this, Observer {
           when (it?.isConnected) {
               true -> {
                   when (it.type) {
                       0 -> Toast.makeText(this, "Wifi turned on", Toast.LENGTH_SHORT).show()
                       1 -> Toast.makeText(this, "Mobile Data turned on", Toast.LENGTH_SHORT).show()
                   }
               }
               false -> {
                   Toast.makeText(this, "No Internet", Toast.LENGTH_SHORT).show()
               }

           }
       })