方法优先级，等待另一种方法完成

Question

我有一个简单的wifi扫描应用程序。

我扫描wifis并将它们保存在List中。当我尝试添加ListView时，它始终为null，但在接收器类中我可以访问它们。如何在列表前填写List？这是我的代码：

  

注意：我先扫描​​然后创建片段。

WifiReceiver Class

class WifiReceiver : BroadcastReceiver{
    public static List<ScanResult> wifiList;
    public override async void OnReceive(Context context, Intent intent) {

        WifiManager wifiManager = (WifiManager)Application.Context.GetSystemService(Context.WifiService);
        wifiList = wifiManager.ScanResults.ToList();
        await Task.Delay(TimeSpan.FromSeconds(1));
        wifiManager.StartScan();
    }
}

WifiListFragment Class

public class WifiListFragment : ListFragment {
    public override void OnCreate(Bundle savedInstanceState) {
        base.OnCreate(savedInstanceState);

        List<ScanResult> wifiList = WifiReceiver.wifiList.ToList();
        List<string> eliminatedWifi = new List<string>();



        //Some eliminations


        ArrayAdapter<string> adapter = new ArrayAdapter<string>(Application.Context, Resource.Layout.WifiListRow, eliminatedWifi);
        ListAdapter = adapter;

    }

    public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.Inflate(Resource.Layout.WifiListFragment, container, false);
        return view;
    }


    public override void OnListItemClick(ListView l, View v, int position, long id) {
        base.OnListItemClick(l, v, position, id);

    }
}