public class NetUtil {
    public static final int NETWORN_NONE = 0;//无网络
    public static final int NETWORN_WIFI = 1;//wife
    public static final int NETWORN_MOBILE = 2;//手机

    /**
     * 获取当前网络的状态
     * @param context
     * @return
     */
    public static int getNetworkState(Context context) {
        ConnectivityManager connManager = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);

        // Wifi
        State state = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI)
                .getState();
        if (state == State.CONNECTED || state == State.CONNECTING) {
            return NETWORN_WIFI;
        }

        // 3G
        state = connManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE)
                .getState();
        if (state == State.CONNECTED || state == State.CONNECTING) {
            return NETWORN_MOBILE;
        }
        return NETWORN_NONE;
    }

    /**
     * 判断是否有网络
     * @param context
     * @return
     */
    public static boolean isNetConnected(Context context) {
        boolean isNetConnected;
        // 获得网络连接服务
        ConnectivityManager connManager = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = connManager.getActiveNetworkInfo();
        if (info != null && info.isAvailable()) {
//				String name = info.getTypeName();
//				L.i("当前网络名称：" + name);
            isNetConnected = true;
        } else {
            L.i("没有可用网络");
            isNetConnected = false;
        }
        return isNetConnected;
    }
}

文章名称：Android学习--判断当前设备的网络状态
网页网址：http://cdweb.net/article/gdjpoe.html