CODEWITHSUNDEEP
xamarinxamarin.formsmaui
Pavlo Datsiuk
Pavlo Datsiuk

Reputation: 1118

How to convert my universal Xamarin.Forms renderer to a MAUI handler?

Could someone help me understand how to correctly convert a custom renderer to a .NET MAUI handler?

In Xamarin.Forms, I have a universal renderer that I can attach to any user control. I override methods like public override void Draw(Android.Graphics.Canvas canvas) to draw custom content directly on the controls. This approach is convenient because it doesn't require wrapping the controls with additional views — it's straightforward and efficient.

Now, I'm trying to migrate this to .NET MAUI. I've attempted using ElementHandler<XF, A> and ViewHandler<XF, A>, but both approaches seem to require creating a platform view, which adds complexity.

Could you provide guidance on how to achieve similar functionality in .NET MAUI without the need to create additional platform views? What's the best practice for this scenario in MAUI?

[assembly: ExportRenderer(typeof(XFUserControl1), typeof(MyEffectRenderer<Xamarin.Forms.View, Android.Views.View>))]
[assembly: ExportRenderer(typeof(XFUserControl2), typeof(MyEffectRenderer<Xamarin.Forms.View, Android.Views.View>))]
[assembly: ExportRenderer(typeof(XFUserControl3), typeof(MyEffectRenderer<Xamarin.Forms.View, Android.Views.View>))]
[assembly: ExportRenderer(typeof(XFUserControl4), typeof(MyEffectRenderer<Xamarin.Forms.View, Android.Views.View>))]
[assembly: ExportRenderer(typeof(XFUserControl5), typeof(MyEffectRenderer<Xamarin.Forms.View, Android.Views.View>))]
namespace MyApp.Droid.CustomRenderers
{
    public class MyEffectRenderer<XF, A>
        : ViewRenderer<XF, A>
            where XF : Xamarin.Forms.View
            where A : Android.Views.View
    {

        public MyEffectRenderer(Context context)
            : base(context)
        {

        }

        public override void Draw(Android.Graphics.Canvas canvas)
        {
            base.Draw(canvas);

            // do my custom magic here
        }

    } 
}

Upvotes: 2

Views: 200

Answers (1)

Pavlo Datsiuk
Pavlo Datsiuk

Reputation: 1118

I have found that this can be achieved in 2 ways:

  1. Continue using Maui.Controls.Handlers.Compatibility.ViewRenderer<XF, A> which doesn't require .UseMauiCompatibility() and use your custom renderer as a handler handlers.AddHandler<XFUserControl1, MyEffectRenderer<XFUserControl1, Android.Views.View>>();.

  2. Implement ContentViewGroup if your control is based on ContentView, which is more in line with the MAUI approach.

                ContentViewHandler.PlatformViewFactory = (viewHandler) => {
                    if (viewHandler.VirtualView is XFUserControl1)
                        return new CustomContentViewGroup(viewHandler.Context);
                    else
                        return null;
                };

                public class CustomContentViewGroup : ContentViewGroup
                {
                    public CustomContentViewGroup(Context context) 
                        : base(context)
                    {
                    }
                            
                    protected override void OnDraw(Canvas canvas)
                    {
                        base.OnDraw(canvas);
                    }   
                }

related link: https://github.com/dotnet/maui/discussions/23090

Upvotes: 0

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