OnCreateView（）在OnCreate（）完成之前发生，导致

Question

我有一个Android片段，它实际上显示了一个自定义ListView。我的片段看起来像这样：

public class ResultSummaryFragment : Android.Support.V4.App.Fragment
    {
        private List<ResultSummary> data;

        public override async void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            ISharedPreferences preferences = Application.Context.GetSharedPreferences("UserInfo", FileCreationMode.Private);
            string id = preferences.GetString("ID", string.Empty);

            if (id != null)
            {
                RunnerData RunnerData = new RunnerData(id);
                // This is not happening before OnCreateView?
                data = await RunnerData.GetAllResults();
            }
        }

        public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            Context context = Application.Context;

            View view = inflater.Inflate(Resource.Layout.results_summary_view, container, false);
            ListView listview = view.FindViewById<ListView>(Resource.Id.AllResultsListView);

            //data is being passed in as null...
            ResultsSummaryListAdapter adapter = new ResultsSummaryListAdapter(context, data);
            listview.Adapter = adapter;

            return view;
        }
    }

问题在于，传递到data的ResultsSummaryListAdapter为空，因为OnCreateView()代码似乎在data = await RunnerData.GetAllResults();返回之前就已执行。我绝对确定这确实会返回数据（由于下载时间可能会花费一些时间）。

我在这里做错了什么？

我觉得更好的方法是实例化片段，开始获取数据，然后触发以下代码：

ResultsSummaryListAdapter adapter = new ResultsSummaryListAdapter(context, data);
listview.Adapter = adapter;

我不确定如何在Android中执行此操作。

Answer 1

我没有看到在您的OnCreate方法中进行API调用的目的，因为您没有使用它。尝试将其移至OnCreateView方法。我已经更改了数据条件（空检查），只是为了确保API调用仅发生一次。

public class ResultSummaryFragment : Android.Support.V4.App.Fragment
{
    private List<ResultSummary> data;

    public override async View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        Context context = Application.Context;

        View view = inflater.Inflate(Resource.Layout.results_summary_view, container, false);
        ListView listview = view.FindViewById<ListView>(Resource.Id.AllResultsListView);

        ISharedPreferences preferences = Application.Context.GetSharedPreferences("UserInfo", FileCreationMode.Private);
        string id = preferences.GetString("ID", string.Empty);

        if (id != null && data == null)
        {
            RunnerData RunnerData = new RunnerData(id);
            // This is not happening before OnCreateView?
            data = await RunnerData.GetAllResults();
        }

        //Now, your compiler knows that you need data and it will wait until data is obtained.
        ResultsSummaryListAdapter adapter = new ResultsSummaryListAdapter(context, data);
        listview.Adapter = adapter;

        return view;
    }
}