protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            // Create your application here
            SetContentView(Resource.Layout.Volume);
            EditText valueToConvert = FindViewById <EditText>(Resource.Id.ValueToConvertVolume);
            TextView convertedValue = FindViewById <TextView>(Resource.Id.convertedValueVolume);
            Spinner  spinnerA       = FindViewById <Spinner>(Resource.Id.VolumeSpinnerA);
            Spinner  spinnerB       = FindViewById <Spinner>(Resource.Id.VolumeSpinnerB);

            spinnerA.Prompt        = "Select unit";
            spinnerA.ItemSelected += new EventHandler <AdapterView.ItemSelectedEventArgs>(volumeSpinner_ItemSelectedA);
            spinnerB.ItemSelected += new EventHandler <AdapterView.ItemSelectedEventArgs>(volumeSpinner_ItemSelectedB);
            var volumeAdapter = ArrayAdapter.CreateFromResource(this, Resource.Array.VolumeSpinnerArray, Android.Resource.Layout.SimpleSpinnerItem);

            volumeAdapter.SetDropDownViewResource(Android.Resource.Layout.SimpleSpinnerDropDownItem);
            spinnerA.Adapter            = volumeAdapter;
            spinnerB.Adapter            = volumeAdapter;
            valueToConvert.TextChanged += (object sender, Android.Text.TextChangedEventArgs e) => {
                if (!(String.Equals(unit_origin, "--Choose a Unit--", StringComparison.Ordinal) ||
                      String.Equals(unit_result, "--Choose a Unit--", StringComparison.Ordinal) ||
                      String.Equals(unit_origin, "default", StringComparison.Ordinal) ||
                      String.Equals(unit_result, "default", StringComparison.Ordinal)) &&
                    !string.IsNullOrEmpty(valueToConvert.Text))
                {
                    convertedValue.Text = VolumeConvert.Convert(unit_origin, unit_result, Convert.ToDouble(valueToConvert.Text)).ToString();
                }
                if (string.IsNullOrEmpty(valueToConvert.Text))
                {
                    convertedValue.Text = valueToConvert.Text;
                }
            };
        }
        /*
         * Event handler for the spinner of result unit
         */
        private void volumeSpinner_ItemSelectedB(object sender, AdapterView.ItemSelectedEventArgs e)
        {
            Spinner  spinner        = (Spinner)sender;
            EditText valueToConvert = FindViewById <EditText>(Resource.Id.ValueToConvertVolume);
            TextView convertedValue = FindViewById <TextView>(Resource.Id.convertedValueVolume);
            string   chosenunit     = (string)spinner.GetItemAtPosition(e.Position);
            string   choose         = "--Choose a Unit--";

            if (String.Equals(chosenunit, choose, StringComparison.Ordinal))
            {
                unit_result = "default";
            }
            else
            {
                unit_result = chosenunit;
                if (!(String.Equals(unit_origin, "default", StringComparison.Ordinal) || string.IsNullOrEmpty(valueToConvert.Text)))
                {
                    convertedValue.Text = VolumeConvert.Convert(unit_origin, unit_result, Convert.ToDouble(valueToConvert.Text)).ToString();
                }
            }
        }