Click Method inside Getview Called multiple times

问题

I want click method to be called only once, what can I do get this result? here's my code:

        public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View result = convertView;
        if (result == null)
        {
            result = LayoutInflater.From(_Context).Inflate(Resource.Layout.DiagnoseTemplateLayout, null, false);
        }
        TextView textView = result.FindViewById<TextView>(Resource.Id.DiagnoseTemplateTextView);
        textView.Text = _Diagnoses[position].Description;
        Button button = result.FindViewById<Button>(Resource.Id.DeleteDiagnoseTemplateButton);
        button.Tag = _Diagnoses[position].Key;
        button.Click += delegate
        {
            if (_Diagnoses[position] != null)
            {
                AlertDialog.Builder builder = new AlertDialog.Builder(_Context);
                builder.SetTitle("Varning");
                builder.SetMessage("Delating selected item?");
                builder.SetPositiveButton("YES", delegate
                {
                    SuperBillAddActivity.SuperBill.Diagnoses.Remove(_Diagnoses[position]);
                    SuperBillAddActivity.RefreshLists();
                });
                builder.SetNegativeButton("NO", delegate { });
                builder.Show();
            }
        };
        return result;
    }

This method is called 3 times button.Click += delegate starting from position from where is button we clicked

        public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View result = convertView;
        if (result == null)
        {
            result = LayoutInflater.From(_Context).Inflate(Resource.Layout.DiagnoseTemplateLayout, null, false);
        }
        TextView textView = result.FindViewById<TextView>(Resource.Id.DiagnoseTemplateTextView);
        textView.Text = _Diagnoses[position].Description;
        Button button = result.FindViewById<Button>(Resource.Id.DeleteDiagnoseTemplateButton);
        button.Tag = _Diagnoses[position].Key;
        button.Click += delegate
        {
            if ((_Clicked) && (_Diagnoses[position] != null))
            {
                _Clicked = !_Clicked;
                AlertDialog.Builder builder = new AlertDialog.Builder(_Context);
                builder.SetTitle("Varning");
                builder.SetMessage("Delating selected item?");
                builder.SetPositiveButton("YES", delegate
                {
                    _Clicked = !_Clicked;
                    SuperBillAddActivity.SuperBill.Diagnoses.Remove(_Diagnoses[position]);
                    SuperBillAddActivity.RefreshLists();
                });
                builder.SetNegativeButton("NO", delegate 
                {
                    _Clicked = !_Clicked;
                });
                builder.Show();
            }
        };
        return result;
    }

_Clicked <- I implemented this and now the problem is solved but I don't like this way of putting a code. is there an alternative to this? also, i'm interested why first code worked the way it did.

回答1:

GetView is called multiple times, in consequence your doing button.Click += delegate multiples times too. And this is the reason why your getting too much calls in Click.

Try:

Button button;
if (result == null)
{
    result = LayoutInflater.From(_Context).Inflate(Resource.Layout.DiagnoseTemplateLayout, null, false);
    button = result.FindViewById<Button>(Resource.Id.DeleteDiagnoseTemplateButton);
    button.Click += delegate {...}

}
TextView textView = result.FindViewById<TextView>(Resource.Id.DiagnoseTemplateTextView);
textView.Text = _Diagnoses[position].Description;
button.Tag = _Diagnoses[position].Key;

来源：https://stackoverflow.com/questions/38263854/click-method-inside-getview-called-multiple-times

标签

android

methods

Xamarin

getview