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

public class NetworkStateReceiver extends BroadcastReceiver {

    public void onReceive(Context context, Intent intent) {
        Log.d(TAG, "tttCONNECTIVITY CHANGED");
    }
}