Here you can find the source of isNetworkAvailable(Activity mainActivity)
public static boolean isNetworkAvailable(Activity mainActivity)
//package com.java2s; import android.app.Activity; import android.content.Context; import android.net.ConnectivityManager; import android.net.NetworkInfo; public class Main { public static boolean isNetworkAvailable(Activity mainActivity) { ConnectivityManager connectivityManager = (ConnectivityManager) mainActivity .getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo activeNetworkInfo = connectivityManager .getActiveNetworkInfo(); return activeNetworkInfo != null && activeNetworkInfo.isConnected(); }/*from w w w. j av a 2 s. com*/ }