1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.tv.util; 18 19 import android.net.ConnectivityManager; 20 import android.net.NetworkInfo; 21 import android.support.annotation.Nullable; 22 import android.support.annotation.WorkerThread; 23 import java.io.IOException; 24 import java.net.HttpURLConnection; 25 import java.net.URL; 26 27 /** A utility class to check the connectivity. */ 28 @WorkerThread 29 public class NetworkUtils { 30 private static final String GENERATE_204 = "http://clients3.google.com/generate_204"; 31 32 /** Checks if the internet connection is available. */ isNetworkAvailable(@ullable ConnectivityManager connectivityManager)33 public static boolean isNetworkAvailable(@Nullable ConnectivityManager connectivityManager) { 34 if (connectivityManager == null) { 35 return false; 36 } 37 NetworkInfo info = connectivityManager.getActiveNetworkInfo(); 38 if (info == null || !info.isConnected()) { 39 return false; 40 } 41 HttpURLConnection connection = null; 42 try { 43 connection = (HttpURLConnection) new URL(GENERATE_204).openConnection(); 44 connection.setInstanceFollowRedirects(false); 45 connection.setDefaultUseCaches(false); 46 connection.setUseCaches(false); 47 if (connection.getResponseCode() == HttpURLConnection.HTTP_NO_CONTENT) { 48 return true; 49 } 50 } catch (IOException e) { 51 // Does nothing. 52 } finally { 53 if (connection != null) { 54 connection.disconnect(); 55 } 56 } 57 return false; 58 } 59 NetworkUtils()60 private NetworkUtils() {} 61 } 62