Question

在我的应用程序中，我需要检查设备是否已连接到Internet。我尝试使用ConnectivityManager但它没有给出100％精确的结果。例如，我可能有一个Wi-Fi连接，但仍然无法访问互联网资源。在我的情况下，我必须打开VPN连接，在我连接到wi-fi之后，才能真正访问互联网。所以使用ConnectivityManager的方法不起作用。

所以，关于上述问题 - 我应该写一个手动的http请求以确保还是有另一种方式？

这是我正在使用的一些代码

ConnectivityManager cm =  (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected() && cm.getActiveNetworkInfo().isAvailable();

Answer 1

是的，你是对的，要检查你是否可以上网，你需要明确地测试它。如果您需要HTTP访问权限，可以尝试连接到以后想要连接的主机。

但是，您应该使用稍后要使用的连接方法。 HTTP可以工作，但不能FTP。因此，如果您需要FTP访问，则应进行测试。

如果您还想获得外部IP，可以使用此方法：

public static InetAddress getExternalIp() throws IOException {
    URL url = new URL("http://automation.whatismyip.com/n09230945.asp");
    URLConnection connection = url.openConnection();
    connection.addRequestProperty("Protocol", "Http/1.1");
    connection.addRequestProperty("Connection", "keep-alive");
    connection.addRequestProperty("Keep-Alive", "1000");
    connection.addRequestProperty("User-Agent", "Web-Agent");

    Scanner s = new Scanner(connection.getInputStream());
    try {
        return InetAddress.getByName(s.nextLine());
    } finally {
        s.close();
    }
}

如果您从此方法成功获得了IP地址，则可以通过HTTP连接到该地址。

Answer 2

我认为不是每次都要检查互联网连接，而是将ConnectionTimeout设置为HTTPRequest，这是最佳方式，

try
  {

   HttpGet request = new HttpGet(url));
   HttpParams httpParameters = new BasicHttpParams();
   // Set the timeout in milliseconds until a connection is established.
   // The default value is zero, that means the timeout is not used. 
   int timeoutConnection = 60000;
   HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
   // Set the default socket timeout (SO_TIMEOUT) 
   // in milliseconds which is the timeout for waiting for data.
   int timeoutSocket = 60000;
   HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
   // create object of DefaultHttpClient    
   DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters);
   request.addHeader("Content-Type", "application/json");
   HttpResponse response = httpClient.execute(request);
   // get response entity
   HttpEntity entity = response.getEntity();
   // convert entity response to string

     if (entity != null)
      {
         result = EntityUtils.toString(entity);
      }

   }
 catch (SocketException e)
  {
     return "-222" + e.toString();
  }
 catch (Exception e)
  {
     return "-333" + e.toString();
  }

Answer 3

试试这个，

     private boolean checkInternetConnection() {
     try {

            ConnectivityManager nInfo = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            nInfo.getActiveNetworkInfo().isConnectedOrConnecting(); 

            ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo netInfo = cm.getActiveNetworkInfo();
            if (netInfo != null && netInfo.isConnectedOrConnecting()) { 
                return true;
            } else { 
                return false; }

        } catch (Exception e) {
            return false;
        }
    }

它非常适合我...

希望有所帮助

Answer 4

试试这个，

NetworkInfo ActiveNetwork;
String Isconnected="";
ConnectivityManager connectivitymanager;
connectivitymanager=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
Connection con=new Connection();
try
{           
    ActiveNetwork=connectivitymanager.getActiveNetworkInfo();
    Isconnected="true";                 
}
catch(Exception error)
{
    IsConnected="false";
}

Answer 5

试试这个

private void MyCheckinternet() {
        // TODO Auto-generated method stub
        ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
            if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED || 
                    connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED) {
                //we are connected to a network
                connected = true;
            }
            else
            {
                connected = false;
    }
}

检查真实的互联网连接

5 个答案: