Intent action for network events in android sdk

Here's a working example:

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

<receiver android:name=".receiver.ConnectivityReceiver">
    <intent-filter>
        <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
    </intent-filter>
</receiver>

.

public class ConnectivityReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d(ConnectivityReceiver.class.getSimpleName(), "action: "
                + intent.getAction());
    }

}

yanchenko's answer is very much useful, i am just simplifying a little bit to get connection status, please modify onReceive as below :

public class ConnectivityReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d(ConnectivityReceiver.class.getSimpleName(), "action: "
                + intent.getAction());
        MyConstants.IS_NETWORK_AVAILABLE = haveNetworkConnection(context);
        //IS_NETWORK_AVAILABLE this variable in your activities to check networkavailability.

    } 


    private boolean haveNetworkConnection(Context context) {
        boolean haveConnectedWifi = false;
        boolean haveConnectedMobile = false;

        ConnectivityManager cm = (ConnectivityManager)   context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo[] netInfo = cm.getAllNetworkInfo();
        for (NetworkInfo ni : netInfo) {
            if (ni.getTypeName().equalsIgnoreCase("WIFI"))
                if (ni.isConnected())
                    haveConnectedWifi = true;
            if (ni.getTypeName().equalsIgnoreCase("MOBILE"))
                if (ni.isConnected())
                    haveConnectedMobile = true;
        }
        return haveConnectedWifi || haveConnectedMobile;    
    }
}