Question

有人可以提供更好，更快的方式来检查Google是否在Android中可用吗？我观察到connectiontimeout在给定的time_out中没有停止。相反，它需要一分多钟..

    public static boolean isConnected(Context context){
            NetworkInfo info = Connectivity.getNetworkInfo(context);
            return (info != null && info.isConnected());
        }
        public boolean checkInternetConnectivity() {

                try {
                    HttpURLConnection urlc = (HttpURLConnection) (new URL(
                            "http://www.google.com").openConnection());
                    urlc.setRequestProperty("User-Agent", "Test");
                    urlc.setRequestProperty("Connection", "close");
                    urlc.setConnectTimeout(2000);
                    urlc.setReadTimeout(3000);
                    urlc.connect();
                    isInterNetAvailable = true;
                    return (urlc.getResponseCode() == 200);
                } catch (IOException e) {
                    isInterNetAvailable = false;
                    return (false);
                }
            }
public String getNWConnectivityText() {     


        if (Connectivity.isConnected(getSherlockActivity()) == true) {

            if (checkInternetConnectivity() == true) {
//          if (true == Connectivity.isConnectingToInternet(getSherlockActivity())) {
//              if (true == Connectivity.isDataAvailable(getSherlockActivity())) {              

                return "google is available";
            } else {
                return "google is not available";
            }

        } else {
            return "no connectivity" + "\t";
        }
    }

Answer 1

除@ astral-projection的解决方案外，您可以简单地声明Socket。我在我的许多项目中使用以下代码，超时肯定有效。

Socket socket;
final String host = "www.google.com";
final int port = 80;
final int timeout = 30000;   // 30 seconds

try {
  socket = new Socket();
  socket.connect(new InetSocketAddress(host, port), timeout);
}
catch (UnknownHostException uhe) {
  Log.e("GoogleSock", "I couldn't resolve the host you've provided!");
}
catch (SocketTimeoutException ste) {
  Log.e("GoogleSock", "After a reasonable amount of time, I'm not able to connect, Google is probably down!");
}
catch (IOException ioe) {
  Log.e("GoogleSock", "Hmmm... Sudden disconnection, probably you should start again!");
}

但是，这可能很棘手。正好在UnknownHostException s，可能需要更长时间才能超时，大约45秒 - 但另一方面，这通常发生在你无法解析主机时，这更像是意味着你的互联网访问错误配置了DNS解析（这是不可能的）。

无论如何，如果你想对冲你的赌注，你可以通过两种方式来解决这个问题：

请勿使用主机，而是使用IP地址。您可以在主机上多次使用ping获取多个Google的IP。例如：
```
shut-up@i-kill-you ~/services $ ping www.google.com
PING www.google.com (173.194.40.179) 56(84) bytes of data.
```
另一种解决方法是启动WatchDog线程并在所需时间后完成连接尝试。显然，强制整理意味着没有成功，所以在你的情况下，谷歌会失败。

----编辑----

我正在添加一个示例，说明在这种情况下如何实现看门狗。请记住，这是一种甚至不需要发生的情况的解决方法，但如果您确实需要，它应该可以解决问题。我将离开原始代码，以便您可以看到差异：

Socket socket;

// You'll use this flag to check wether you're still trying to connect
boolean is_connecting = false;

final String host = "www.google.com";
final int port = 80;
final int timeout = 30000;   // 30 seconds

// This method will test whether the is_connecting flag is still set to true
private void stillConnecting() {
  if (is_connecting) {
    Log.e("GoogleSock", "The socket is taking too long to establish a connection, Google is probably down!");
  }
}

try {
  socket = new Socket();
  is_connecting = true;
  socket.connect(new InetSocketAddress(host, port), timeout);

  // Start a handler with postDelayed for 30 seconds (current timeout value), it will check whether is_connecting is still true
  // That would mean that it won't probably resolve the host at all and the connection failed
  // postDelayed is non-blocking, so don't worry about your thread being blocked
  new Handler().postDelayed(
    new Runnable() {
      public void run() {
        stillConnecting();
      }
    }, timeout);
}
catch (UnknownHostException uhe) {
  is_connecting = false;
  Log.e("GoogleSock", "I couldn't resolve the host you've provided!");
  return;
}
catch (SocketTimeoutException ste) {
  is_connecting = false;
  Log.e("GoogleSock", "After a reasonable amount of time, I'm not able to connect, Google is probably down!");
  return;
}
catch (IOException ioe) {
  is_connecting = false;
  Log.e("GoogleSock", "Hmmm... Sudden disconnection, probably you should start again!");
  return;
} 

// If you've reached this point, it would mean that the socket went ok, so Google is up
is_connecting = false;

注意：我假设你正在这样做（我的意思是，不在主用户界面中）并且这是在一个线程内（你可以使用AsyncTask，一个线程），服务中的线程......）。

Answer 2

广播接收器可能会派上用场：

BroadcastReceiver networkStateReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(getActivity(), "Connection reset, rolling back", Toast.LENGTH_LONG).show();

        }
    };

它也是电池友好的。

也不要忘记取消注册:( onDestroy（））

getActivity().unregisterReceiver(networkStateReceiver);

Answer 3

正如Astral所说，你可以使用BroadcastReceiver来获取互联网连接的状态，这是检查互联网连接的最佳方式;但是如果您尝试连接的服务器已关闭或没有响应，那么只是为了安全起见创建一个超时循环。如果在特定时间内没有从服务器回复，则取消请求并向用户显示错误消息。

Android：如何检查Google是否可用？

3 个答案: