检查片段中的网络连接

Question

我试图在SherlockFragment中检查网络连接,但无法识别getSystemService()方法.

以下是我的代码(来自http://developer.android.com/training/basics/network-ops/connecting.html)

    ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
    if (networkInfo != null && networkInfo.isConnected()) {
        // fetch data
    } else {
        // display error
    }

提前致谢

Answer 1

该方法getSystemService()未在片段上定义,因此首先使用该活动getActivity(),例如:

ConnectivityManager connMgr = (ConnectivityManager) getActivity()
                             .getSystemService(Context.CONNECTIVITY_SERVICE);

NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();

if (networkInfo != null && networkInfo.isConnected()) {
    // fetch data
} else {
    // display error
}

ps:additianal note:如果片段在没有附加到任何活动的情况下存在潜在风险,请检查是否先getActivity()返回null.

干杯!