NetworkChangeReceiver.java

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

import com.yarolegovich.lovelydialog.LovelyInfoDialog;

public class NetworkChangeReceiver extends BroadcastReceiver {
    Context context;
    boolean isConnected = false;

    @Override
    public void onReceive(final Context context, final Intent intent) {
        isNetworkAvailable(context); //receiver çalıştığı zaman çağırılacak method
    }

    private boolean isNetworkAvailable(Context context) {
        ConnectivityManager connectivity = (ConnectivityManager)
                context.getSystemService(Context.CONNECTIVITY_SERVICE); //Sistem ağını dinliyor internet var mı yok mu

        if (connectivity != null) {
            NetworkInfo[] info = connectivity.getAllNetworkInfo();
            if (info != null) {
                for (int i = 0; i < info.length; i++) {
                    if (info[i].getState() == NetworkInfo.State.CONNECTED) {

                        if(!isConnected){ //internet varsa
                            isConnected = true;
                        }
                        return true;
                    }
                }
            }
        }
        isConnected = false;

        new LovelyInfoDialog(context)
                .setTopColorRes(R.color.colorPrimary)
                .setIcon(R.drawable.ic_info_outline_black_24dp)
                //This will add Don't show again checkbox to the dialog. You can pass any ID as argument
                .setTitle(R.string.info_title)
                .setMessage(R.string.info_message)
                .setCancelable(false)
                .show();

        return false;

    }
}