private void callapi()
        {
            ContentView content = new ContentView();

            StackLayout data = new StackLayout();

            Label Baseurl = new Label
            {
                Text = GlobalVar.BaseUrl
            };

            data.Children.Add(Baseurl);

            Entry text = new Entry
            {
                Placeholder      = "Endpoint",
                PlaceholderColor = Color.Gray,
                TextColor        = Color.Black
            };

            data.Children.Add(text);
            text.TextChanged += (s, e) =>
            {
                Endpoint = text.Text;
            };

            Button Save = new Button {
                Text = "Call"
            };

            Save.Clicked += (s, e) =>
            {
                Navigation.PopPopupAsync();
                Sample.CallApiSample(this);
            };
            data.Children.Add(Save);

            content.Content = data;
            Navigation.PushPopupAsync(new PopUpPage(content, true));
        }