Xamrine Http call not returning response

Question

I wanted to fetch and display data but its not working and after this line

var response = await client.GetAsync(uri).ConfigureAwait(false);

code never executed not even throw an exception

public async Task<List<Restresponse>> RefreshDataAsync()
{
    var Items = new List<Restresponse>();
    try
    {
        HttpClient client = new HttpClient();
        var uri = new Uri(string.Format("https://jsonplaceholder.typicode.com/posts", string.Empty));
        var response = await client.GetAsync(uri).ConfigureAwait(false);
        if (response.IsSuccessStatusCode)
        {
            var content = await response.Content.ReadAsStringAsync().ConfigureAwait(false); ;
           // Items = JsonConvert.DeserializeObject<List<TodoItem>>(content);
        }
    }
    catch (Exception e)
    {
        Log.WriteLine(LogPriority.Debug, "EXception from restservice", e.Message);
    }
    return Items;

}

and i have called this functiion in OncreateView in fragment

public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            View view = inflater.Inflate(Resource.Layout.recycleview, container, false);

            mRecyclerView = view.FindViewById<RecyclerView>(Resource.Id.recyclerView);

            mLayoutManager = new LinearLayoutManager(this.Activity);
            mRecyclerView.SetLayoutManager(mLayoutManager);

            // Prepare the data source:
            listItem = new List<Restresponse>();
            try
            {
                listItem = RefreshDataAsync().Result;

                // Instantiate the adapter and pass in its data source:
                mAdapter = new RecycleViewAdapter(listItem, this.Activity);

                // Plug the adapter into the RecyclerView:
                mRecyclerView.SetAdapter(mAdapter);
            }
            catch (System.Exception e)
            {
                Log.WriteLine(LogPriority.Debug, "EXception from fragmenbt", e.Message);
            }
            return view;
        }

Answer 1

Sure you are getting a deadlock.

If you are calling from constructor or event RefreshDataAsync().Result; you should remove .ConfigureAwait(false); from function because if you are in main thread it will never finish.

another option after comments I think that if you need async process your best way is use OnResume after creating view.

    public async override void OnResume()
    {
        base.OnResume();
        try
        {
            listItem = RefreshDataAsync().Result;

            // Instantiate the adapter and pass in its data source:
            mAdapter = new RecycleViewAdapter(listItem, this.Activity);

            // Plug the adapter into the RecyclerView:
            mRecyclerView.SetAdapter(mAdapter);
        }
        catch (System.Exception e)
        {
            Log.WriteLine(LogPriority.Debug, "EXception from fragmenbt", e.Message);
        }
    } 

Don't forget remove Try/catch block from OnCreateView where you call RefreshDataAsync()

---

Full code fragment:

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

            try
            {
                View view = inflater.Inflate(Resource.Layout.recycleview, container, false);

                mRecyclerView = view.FindViewById<RecyclerView>(Resource.Id.recyclerView);

                mLayoutManager = new LinearLayoutManager(this.Activity);
                mRecyclerView.SetLayoutManager(mLayoutManager);
            }
            catch (Exception)
            {

                Log.WriteLine(LogPriority.Debug, "EXception from fragment inside OnCreateView", e.Message);
            }



        }

        public async override void OnResume()
        {
            base.OnResume();
            // Prepare the data source:
            try
            {
                using (var client = new HttpClient())
                {
                    var uri = "jsonplaceholder.typicode.com/posts";
                    var result = await client.GetStringAsync(uri);
                    var Restresponse = JsonConvert.DeserializeObject<List<Restresponse>>(result);
                    mAdapter = new RecycleViewAdapter(Restresponse, this.Activity);
                    mRecyclerView.SetAdapter(mAdapter);
                }
            }
            catch (System.Exception e)
            {
                Log.WriteLine(LogPriority.Debug, "EXception from fragment inside OnResume", e.Message);
            }
        }