在我的應(yīng)用程序中，我想測(cè)試設(shè)備是否已連接到互聯(lián)網(wǎng)并相應(yīng)地運(yùn)行一些代碼，并且在搜索互聯(lián)網(wǎng)之后，以下代碼顯然應(yīng)該可以工作：ConnectivityManager connMgr = (ConnectivityManager)getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();但事實(shí)并非如此。調(diào)試器告訴我名稱(chēng)getActivity在當(dāng)前上下文中不存在此代碼有什么問(wèn)題？這是完整的fragment2.cs文件：using Android.OS;using Android.Support.V4.App;using Android.Views;using Android.Webkit;using Android.Net;using Android.Widget;using System;namespace TabsApp.Fragments{    public class Fragment2 : Fragment    {        public override void OnCreate(Bundle savedInstanceState)        {            base.OnCreate(savedInstanceState);            // Create your fragment here        }        public static Fragment2 NewInstance()        {            var frag2 = new Fragment2 { Arguments = new Bundle() };            return frag2;        }        public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)        {            var ignored = base.OnCreateView(inflater, container, savedInstanceState);            View v = inflater.Inflate(Resource.Layout.fragment2, container, false);            ConnectivityManager connMgr = (ConnectivityManager)getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);            NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();            return v;        }    }}