MAUI: How to migrate a custom render to a handler?

Question

I have a custom render in my Xamarin Forms application and I am trying to migrate it to a Handler in my MAUI application.

My custom render is for removing the under line of Entry. Adding it below:

CustomEntry

	public class CustomEntry : Entry
	{
	}

Under android platform:

	public class CustomEntryRenderer : EntryRenderer
	{
		public CustomEntryRenderer(Context context) : base(context)
		{
		}

		protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
		{
			base.OnElementChanged(e);

			if (Control != null)
			{
				GradientDrawable gd = new GradientDrawable();
				gd.SetColor(global::Android.Graphics.Color.Transparent);
				this.Control.Background = gd;
				this.Control.SetRawInputType(InputTypes.TextFlagNoSuggestions);
			}
		}
	}

Under ios platform:

public class CustomEntryRenderer : EntryRenderer
{
    protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
    {
        base.OnElementChanged(e);

        if (Control != null)
        {
            Control.BorderStyle = UITextBorderStyle.None;
        }
    }
}

Above is the existing custom render code. I want to convert it to Handlers and could you show how I can do that? I didn't get a clear idea after reading the this blog.

Answer 1

Hello,

Handlers can be customized per platform by using conditional compilation, to multi-target code based on the platform.

Wherefore, you can create a method then put the handler in it. Then get the native platform control by handler.PlatformView, for example, handler.PlatformView is edittext in android. then set the background and the set RawInputType directly. that is same for iOS.

    void ModifyEntry()
    {
        Microsoft.Maui.Handlers.EntryHandler.Mapper.AppendToMapping("MyCustomization", (handler, view) =>
        {

           if(view is CustomEntry)
            {
#if ANDROID
                Android.Graphics.Drawables.GradientDrawable gradientDrawable = new Android.Graphics.Drawables.GradientDrawable();
                gradientDrawable.SetColor(global::Android.Graphics.Color.Transparent);
                handler.PlatformView.Background = gradientDrawable;
                handler.PlatformView.SetRawInputType(InputTypes.TextFlagNoSuggestions);
#elif IOS
            handler.PlatformView.BorderStyle = UITextBorderStyle.None;
#endif
            }
       });
    }

If you want to make this handler in the contentpage. you can call this method in the page's constructor. As note, you use the native platform namespace, please use conditional compilation to wrap these specific platform code.

#if ANDROID
using Android.Graphics.Drawables;
using Android.Text;
#elif IOS
using UIKit;
#endif

namespace MauiApp4;
public partial class NewPage1 : ContentPage
{
    public NewPage1()
    {
        InitializeComponent();
       ModifyEntry();
    }

If you want custom control, you can refer to this .NET MAUI control customization with handlers document

Best Regards,

Leon Lu

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