How to check Wifi is connected, but no Internet access in Android

问题

I would like to know why wifi is connected but there is no internet access in Android. How can i check it? My code is:

ConnectivityManager cn=(ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
 NetworkInfo nf=cn.getActiveNetworkInfo();

 if(nf != null && nf.isConnected() )
         {
            Flag2=false;
            Log.e("network--------", "1--------------");

            if (cn.getActiveNetworkInfo().isConnectedOrConnecting())
            {Log.e("network--------", "11111111111111--------------");
             }
            else
            {Log.e("network--------", "2222222222222--------------");
            }
        }

 else 
         {
            Log.e("network--------", "2--------------");
 }

回答1:

You could try something like this:

public void checkOnlineState() {
    ConnectivityManager CManager =
        (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo NInfo = CManager.getActiveNetworkInfo();
    if (NInfo != null && NInfo.isConnectedOrConnecting()) {
        if (InetAddress.getByName("www.xy.com").isReachable(timeout))
        {  
         // host reachable  
        }
         else
         {    
         // host not reachable  
         }  
    }
    return;
}

dont forget the access

 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Hope it will work :)

回答2:

Use this :

public static boolean isInternetOn(Context context) {
        ConnectivityManager cm = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        // test for connection
        if (cm.getActiveNetworkInfo() != null
                && cm.getActiveNetworkInfo().isAvailable()
                && cm.getActiveNetworkInfo().isConnected()) {
            Log.v(TAG, "Internet is working");
            // txt_status.setText("Internet is working");
            return true;
        } else {
            // txt_status.setText("Internet Connection Not Present");
            Log.v(TAG, "Internet Connection Not Present");
            return false;
        }
    }

Hope this helps.

回答3:

In addition to what you are doing right now,you can use BroadcastReceiver for your application to get notified whenever the connectivity changes by registering <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/> intent.

Have a look at docs: BroadcastReceiver and Connectivity Monitoring for detailed description.

I hope it will be helpful !

回答4:

ConnectivityManager manager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = manager.getActiveNetworkInfo();
        if (info != null && info.isAvailable()) {
            return true;
        }
        return false;

来源：https://stackoverflow.com/questions/16580380/how-to-check-wifi-is-connected-but-no-internet-access-in-android

标签

android

android-networking