Agfdhyk

I'm trying to develop a mobile app on Xamarin Forms platform.I'm getting data from API.API call only happened once only when the application is opened. I'm Listing livescores between teams in a ListView . For example the minutes of the match 25 for now.I'm waiting 2 minutes and nothing changed. The minute is the same on my ListView.When I close and open the app again minute is changing.I just want to make call every 5 second to refresh the data without close the application.
Here is my code.

public List<liveScoreData>liveScore() 

    {

        var result = new List<liveScoreData>();

        try

        {



            Guid guidSifre = Guid.NewGuid();

            string guid = guidSifre.ToString();

            string result = CreateMD5forChecksum(guid);



            using (var client = new WebClient())

            {

                var values = new NameValueCollection();

                values["result"] = result;

                values["guid"] = guid;



                var response = client.UploadValues("http://abcd.com/admin/LiveScore", values);



                var responseString = Encoding.Default.GetString(response);





                var responseResult = JsonConvert.DeserializeObject(responseString);

                result = JsonConvert.DeserializeObject<List<liveScoreData>>(responseResult.ToString());



                Mehmet.liveScoreDataList = result;



            }

        }

        catch (Exception ex)

        {

            var exc = ex;

        }



        return result;



    }

What you can do is implement my special PollingTimer.cs class:

using System;

using System.Threading;

using Xamarin.Forms;



namespace AppNamespace.Helpers

{

    /// <summary>

    /// This timer is used to poll the middleware for new information.

    /// </summary>

    public class PollingTimer

    {

        private readonly TimeSpan timespan;

        private readonly Action callback;



        private CancellationTokenSource cancellation;



        /// <summary>

        /// Initializes a new instance of the <see cref="T:CryptoTracker.Helpers.PollingTimer"/> class.

        /// </summary>

        /// <param name="timespan">The amount of time between each call</param>

        /// <param name="callback">The callback procedure.</param>

        public PollingTimer(TimeSpan timespan, Action callback)

        {

            this.timespan = timespan;

            this.callback = callback;

            this.cancellation = new CancellationTokenSource();

        }



        /// <summary>

        /// Starts the timer.

        /// </summary>

        public void Start()

        {

            CancellationTokenSource cts = this.cancellation; // safe copy

            Device.StartTimer(this.timespan,

                () => {

                    if (cts.IsCancellationRequested) return false;

                    this.callback.Invoke();

                    return true; // or true for periodic behavior

            });

        }



        /// <summary>

        /// Stops the timer.

        /// </summary>

        public void Stop()

        {

            Interlocked.Exchange(ref this.cancellation, new CancellationTokenSource()).Cancel();

        }

    }

}

Then what you can do following that is in your page that you want to make a call every 5 seconds from, in the constructor at the end of it you can write this line of code:

timer = new PollingTimer(TimeSpan.FromSeconds(5), liveScore);

This will run your method every 5 seconds. To make your method work with the pollingtimer you must edit your method to a void and return the value to a global variable like so:

//Make a global variable for your method to access

  List<liveScoreData> globalLiveScore = new List<liveScoreData>();



      public void liveScore() 

        {

            var result = new List<liveScoreData>();

            try

            {



                Guid guidSifre = Guid.NewGuid();

                string guid = guidSifre.ToString();

                string result = CreateMD5forChecksum(guid);







                using (var client = new WebClient())

                {

                    var values = new NameValueCollection();

                    values["result"] = result;

                    values["guid"] = guid;







                    var response = client.UploadValues("http://abcd.com/admin/LiveScore", values);



                    var responseString = Encoding.Default.GetString(response);







                    var responseResult = JsonConvert.DeserializeObject(responseString);

                    result = JsonConvert.DeserializeObject<List<liveScoreData>>(responseResult.ToString());







                    Mehmet.liveScoreDataList = result;





                }

            }

            catch (Exception ex)

            {

                var exc = ex;

            }





            globalLiveScore = result;







        }

Then from there you can check your live score data in other methods. Then in your OnAppearing method you can run

timer.Start();

and in your OnDisappearing method you can run

timer.Stop();

have a play with it and see if you can put it in better places for optimal performance etc.

You could use the System.Threading.Timer object

and simply initialize it like this

`System.Threading.Timer myTimer = new System.Threading.Timer((e) =>

{

    liveScore(); //your function call

}, null, 

TimeSpan.FromSeconds(0), //start immediately

TimeSpan.FromSeconds(5)); //execute every 5 secs`