即使已连接wifi或3G，也请检查互联网连接

Question

I need to check if there is internet connection even if the phone is connected to a wifi network or 3G. I have this code but it says only if connected to a network:

public class ConnectionDetector {

    private Context _context;

    public ConnectionDetector(Context context){
        this._context = context;
    }

    public boolean isConnectingToInternet(){
        ConnectivityManager connectivity = (ConnectivityManager) _context.getSystemService(Context.CONNECTIVITY_SERVICE);
          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)
                      {
                          return true;
                      }

          }
          return false;
    }
}

Answer 1

You can use the following to detect if either 3G or WiFi is connected

ConnectivityManager man = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);

//3G
boolean is3gConnected = man.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).isConnectedOrConnecting();

//Wifi
boolean isWifiConnected = man.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnectedOrConnecting();

Answer 2

I have created this class to get if the user is connected on the internet and what type of connection he has

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.telephony.TelephonyManager;

public class NetWork {

    private static boolean connectionEstablished = false;

    /**
     * get the internet connection of the device
     *
     * @param context
     * @return the type of internet connection
     */
    private static NetWorkTypes getNetwork(Context context) {
        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = cm.getActiveNetworkInfo();

        if (info == null || !info.isConnected())
            return NetWorkTypes.NO_CONNECTION;

        if (info.getType() == ConnectivityManager.TYPE_WIFI)
            return NetWorkTypes.WIFI;

        if (info.getType() == ConnectivityManager.TYPE_MOBILE) {
            int networkType = info.getSubtype();
            switch (networkType) {
                case TelephonyManager.NETWORK_TYPE_GPRS:
                case TelephonyManager.NETWORK_TYPE_EDGE:
                case TelephonyManager.NETWORK_TYPE_CDMA:
                case TelephonyManager.NETWORK_TYPE_1xRTT:
                case TelephonyManager.NETWORK_TYPE_IDEN: // all above for 2G

                case TelephonyManager.NETWORK_TYPE_UMTS:
                case TelephonyManager.NETWORK_TYPE_EVDO_0:
                case TelephonyManager.NETWORK_TYPE_EVDO_A:
                case TelephonyManager.NETWORK_TYPE_HSDPA:
                case TelephonyManager.NETWORK_TYPE_HSUPA:
                case TelephonyManager.NETWORK_TYPE_HSPA:
                case TelephonyManager.NETWORK_TYPE_EVDO_B:
                case TelephonyManager.NETWORK_TYPE_EHRPD:
                case TelephonyManager.NETWORK_TYPE_HSPAP: // all above for 3G

                case TelephonyManager.NETWORK_TYPE_LTE:   // 4G
                    return NetWorkTypes.MOBILE_NETWORK;
                default:
                    return NetWorkTypes.UNKNOWN;
            }
        }
        return NetWorkTypes.UNKNOWN;
    }

    /**
     * check if device is connected on the internet
     *
     * @param context
     * @return true if is connected, false if isn't
     */
    public static boolean isConnected(Context context) {
        NetWorkTypes netWorkType;
        netWorkType = getNetwork(context);
        if (netWorkType == NetWorkTypes.WIFI || netWorkType == NetWorkTypes.MOBILE_NETWORK) {
            connectionEstablished = true;
        } else {
            connectionEstablished = false;
        }
        return connectionEstablished;
    }

    /**
     * @return the boolean that tells if there is connection on the internet
     */
    public static boolean getConnectionEstablished() {
        return connectionEstablished;
    }
}

NetWorkTypes is just an enum. You can return anything else you wish

Answer 3

You say Check *internet* connection even if connected to wifi or 3G , however you implementation will not actually test this, as simply being connected to a WiFi network does not mean that you have internet connectivity. As a suggestion, you could attempt opening a socket to a known host - if the connection is successful, you can be sure that you have network access.

public boolean hasInternetConnectivity() {

    try {
        // connect to google on port 80, the HTTP port
        Socket s = new Socket("www.google.com", 80);

        // the above would have thrown if failed, so we are good
        s.close();
        return true;
    } catch (Exception e) {

        // check logcat to see why it failed, you could then catch and handle each exception independently ( time out, host unknown, end of stream, etc.. )
        e.printStackTrace();

        // the connection has failed, return false
        return false;
}