networking - How to determine Android internet connection?

Question

How can I determine the current internet connection type available to an Android device? e.g. have it return WiFi, 3G, none.

Answer 1

You can use this to determine whether you are connected:

final ConnectivityManager connectManager = (ConnectivityManager)ctx.getSystemService(Context.CONNECTIVITY_SERVICE); // ctx stands for the Context
final NetworkInfo mobile = connectManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
final NetworkInfo wifi   = connectManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI  );

// Return true if connected, either in 3G or wi-fi
return ((mobile != null && mobile.getState() == NetworkInfo.State.CONNECTED) || 
        (wifi   != null && wifi.getState()   == NetworkInfo.State.CONNECTED)   );
}

This code requires the permissions ACCESS_NETWORK_STATE and ACCESS_WIFI_STATE.

EDIT: public NetworkInfo getNetworkInfo (int networkType) has been deprecated in API 21. For API levels higher than 20 you can do as follows:

final Network[] networks = connectManager.getAllNetworks();
boolean connected = false;

for (int ctr = 0; !connected && ctr < networks.length; ++ctr) {
    final NetworkInfo network = connectManager.getNetworkInfo(networks[ctr]);
    final int netType = network.getType();

    connected = (network.getState() == NetworkInfo.State.CONNECTED) &&
            (
                netType == ConnectivityManager.TYPE_MOBILE     ||
                netType == ConnectivityManager.TYPE_WIFI     /*||
                netType == ConnectivityManager.TYPE_WIMAX      ||
                netType == ConnectivityManager.TYPE_ETHERNET */  );
}

return connected;

I limited this code to Wi-Fi and 3G as per the OP's question but it's easy to extend it to newly added connection types such as Ethernet or Wi-Max.