Raven Raven - 13 days ago 13
iOS Question

Custom Rendering on IOS a CardView from Frame

I am trying to make a CardView on IOS Xamarin Forms by subclassing the Frame and making a custom renderer. I want to achieve something like this:

enter image description here

Upon looking into the API on setting a shadow, I've done this:

[assembly: ExportRenderer(typeof(CardView), typeof(CardViewRenderer))]
namespace TrabbleMobile.iOS.CustomRenderers
{
public class CardViewRenderer : FrameRenderer
{
public override void Draw(CGRect rect)
{
var cardView = (CardView)this.Element;

using (var context = UIGraphics.GetCurrentContext())
{
//nfloat cornerRadius = 2;
float shadowOffsetWidth = 2;
float shadowOffsetHeight = 4;
var shadowColor = new CGColor(0, 0, 0, (nfloat)0.5);
var boxColor = new CGColor(255, 255, 255);
var shadowBlur = (float)0.5;
var offset = new CGSize(shadowOffsetWidth, shadowOffsetHeight);

context.SetShadow(offset, shadowBlur, shadowColor);


However, it does not render as it should and no shadow at all.

Answer

I've done this, and the way that I did this is thru custom rendering on IOS and here is the custom renderer code:

    public class CardViewRenderer : FrameRenderer
    {

        public override void Draw(CGRect rect)
        {
            SetupShadowLayer();
            base.Draw(rect);
        }

        void SetupShadowLayer()
        {
            Layer.CornerRadius = 2; // 5 Default
            if (Element.BackgroundColor == Xamarin.Forms.Color.Default)
            {
                Layer.BackgroundColor = UIColor.White.CGColor;
            }
            else
            {
                Layer.BackgroundColor = Element.BackgroundColor.ToCGColor();
            }

            Layer.ShadowRadius = 2; // 5 Default
            Layer.ShadowColor = UIColor.Black.CGColor;
            Layer.ShadowOpacity = 0.4f; // 0.8f Default
            Layer.ShadowOffset = new CGSize(0f, 2.5f);

            if (Element.OutlineColor == Xamarin.Forms.Color.Default)
            {
                Layer.BorderColor = UIColor.Clear.CGColor;
            }
            else
            {
                Layer.BorderColor = Element.OutlineColor.ToCGColor();
                Layer.BorderWidth = 1;
            }

            Layer.RasterizationScale = UIScreen.MainScreen.Scale;
            Layer.ShouldRasterize = true;
        }
    }