//This code for rEad sunset time for any city you enter

//Add refresne
1- Add System.Json
2- Add internet access

// interface
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:minWidth="25px"
    android:minHeight="25px">
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editText1"
        android:hint="City Name" />
    <Button
        android:id="@+id/getWeatherButton"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Get Sunset Time" />
    <TextView
        android:text="_______________"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/textView1" />
</LinearLayout>

// 
//source code
      protected  override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

            // Get our button from the layout resource,
            // and attach an event to it
            //button.Click += async (sender, e) => { }
            Button button = FindViewById<Button>(Resource.Id.getWeatherButton);
            var editText1 = FindViewById<EditText>(Resource.Id.editText1);
            var textView1 = FindViewById<TextView>(Resource.Id.textView1);

            // When the user clicks the button, send the REST request to geonames.org,
            button.Click += async (sender, e) =>
            {
                button.Enabled = false;
                 string url = "https://query.yahooapis.com/v1/public/yql?q=select%20astronomy.sunset%20from%20weather.forecast%20where%20woeid%20in%20(select%20woeid%20from%20geo.places(1)%20where%20text%3D%22"+ editText1 .Text +"%22)&format=json&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys";

                JsonValue json = await FetchWeatherAsync(url);
              //  JsonValue weatherResults = json["query"]["results"];
                string weatherResults = json["query"]["results"]["channel"]["astronomy"]["sunset"].ToString();
                textView1.Text = weatherResults;
                button.Enabled = true;
            };
        }
        private async Task<JsonValue> FetchWeatherAsync(string url)
        {
            // Create an HTTP web request using the URL:
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(new Uri(url));
            request.ContentType = "application/json";
            request.Method = "GET";

            // Send the request to the server and wait for the response:
            using (WebResponse response = await request.GetResponseAsync())
            {
                // Get a stream representation of the HTTP web response:
                using (Stream stream = response.GetResponseStream())
                {
                    // Use this stream to build a JSON document object:
                    JsonValue jsonDoc = await Task.Run(() => JsonObject.Load(stream));
                    Console.Out.WriteLine("Response: {0}", jsonDoc.ToString());

                    // Return the JSON document:
                    return jsonDoc;
                }
            }
        }


//Ref
https://developer.yahoo.com/weather/