Add platform feedback api for sound and haptic feedback by emmauss · Pull Request #21189 · AvaloniaUI/Avalonia

emmauss · 2026-04-14T12:17:05Z

What does the pull request do?

Add audio and haptic feedback for common interact-able controls.
This PR is a rework of #9420 .The api has been stripped down and the core implementation is internal.

namespace Avalonia.Controls
{
    /// <summary>
    /// The feedback type to be triggered for the attached control.
    /// </summary>
    public enum FeedbackType
    {
        /// <summary>
        /// Disables feedback for the attached control
        /// </summary>
        None,
    
        /// <summary>
        /// Triggers the most suitable feedback type based on the feedback effect on the current platform.
        /// </summary>
        Auto,
    
        /// <summary>
        /// If available, triggers only sound feedback for the attached control
        /// </summary>
        Sound,
    
        /// <summary>
        /// If available, triggers only haptic feedback for the attached control
        /// </summary>
        Haptic
    }

    /// <summary>
    /// Defines which action triggered the feedback.
    /// </summary>
    public class FeedbackAction
    {
        internal string Key { get; }
        internal FeedbackAction(string label)
        {
            Key = label;
        }

        /// <summary>
        /// The feedback is related to the Click action
        /// </summary>
        public static FeedbackAction Click { get; } = new FeedbackAction("Click");

        /// <summary>
        /// The feedback is related to the Hold action
        /// </summary>
        public static FeedbackAction Hold { get; } = new FeedbackAction("Hold");
    }
    
    public static class PlatformFeedbackExtensions
    {
        /// <summary>
        /// Performs the specified <see cref="FeedbackEffect"/> on this <see cref="InputElement"/>. The type of feedback to perform is defined in the <see cref="PlatformFeedback.FeedbackTypeProperty"/>
        /// </summary>
        /// <param name="inputElement">The element to trigger the feedback effect on</param>
        /// <param name="feedbackAction">The feedback action relating to the action that triggered it</param>
        public static void PerformFeedback(this InputElement inputElement, FeedbackAction feedbackAction);
    }

    public class PlatformFeedback
    {
        public static readonly AttachedProperty<FeedbackType> FeedbackTypeProperty =
            AvaloniaProperty.RegisterAttached<PlatformFeedback, InputElement, FeedbackType>("FeedbackType", defaultValue: FeedbackType.None);

        public static void SetFeedbackType(InputElement control, FeedbackType feedbackType);

        public static FeedbackType GetFeedbackType(InputElement control);
    }
}

By default, custom controls have feedback disabled. They can enable it using PlatformFeedback.FeedbackType attached property and trigger either sound or haptic feedback based on the set value using PerformFeedback extension method,
e.g. this.PerformFeedback(FeedbackType.Click).

What is the current behavior?

What is the updated/expected behavior with this PR?

How was the solution implemented (if it's not obvious)?

Checklist

Added unit tests (if possible)?
Added XML documentation to any related classes?
Consider submitting a PR to https://github.com/AvaloniaUI/avalonia-docs with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues

avaloniaui-bot · 2026-04-14T13:01:12Z

You can test this PR using the following package version. 12.1.999-cibuild0064816-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2026-04-14T14:38:16Z

You can test this PR using the following package version. 12.1.999-cibuild0064824-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

TomEdwardsEnscape · 2026-04-14T19:28:14Z

+                    FeedbackEffect.Click => UIImpactFeedbackStyle.Light,
+                    FeedbackEffect.LongPress => UIImpactFeedbackStyle.Medium,


iOS has five different feedback styles, but this system only permits the use of two.

What if feedback effects worked like theme variants, so that instead of an enum the parameter is a reference type? Cross-platform values can be defined in Avalonia.Controls and platform-specific values can be defined in Avalonia.iOS, Avalonia.Android, etc.

How would users access those platform specific ones?

By referencing the platform specific projects in their own platform-specific projects.

I'm still not quite clear on how that can be done. View and viewmodels can't access platform specific without DI. If they are like theme variants, then they would have to call PerformFeedback multiple times. First for the crossplatform version, then another for whatever platform they want special effects.
Also, how often would devs want to trigger effects outside the defaults for just 1 platform?

View and viewmodels can't access platform specific without DI.

Huh? People are allowed to make apps which only target one platform. It's quite alright for your views to be defined in a project which references that platform's Avalonia library, e.g. Avalonia.iOS.

But in the project where I used these features, our views were indeed in a platform-agnostic project. So I created a RoutedEventArgs class requesting haptic feedback and defining if it was a "scroll" or "snap". Then in our iOS executable project, I installed a TopLevel handler for that event which translated scroll to Light and snap to Soft and made the appropriate iOS SDK calls.

I think this answers your question about developers triggering effect types other than what you deem the "defaults".

I have no idea what you mean about performing feedback multiple times.

I think its a bit beyond the scope of this pr. The focus here is to provide basic feedback for the built-in controls, while allowing devs to do the same for their custom controls. This is to ensure behavior is the same or native across all platforms that supports some form of feedback.
Devs can create their own feedback system to provide custom effects for their control, but most devs should be good with just the basic effects.

Sure, but anyone doing that must implement everything from scratch. The simple change I suggested above would allow them to use this code.

How would the api look like?

Remove: public enum FeedbackEffect { ... }.

Add: public abstract class FeedbackEffect;, public class ClickFeedbackEffect : FeedbackEffect;, and so on.

Everything else stays the same. You can define an internal constructor for the abstract class if you don't want third parties deriving their own effects.

If we go this API route, I think TextTrimming-like API is a better fit.

Avalonia/src/Avalonia.Base/Media/TextTrimming.cs

Lines 9 to 21 in a3c571b

public abstract class TextTrimming

{

internal const string DefaultEllipsisChar = "\u2026";

/// <summary>

/// Text is not trimmed.

/// </summary>

public static TextTrimming None { get; } = new TextNoneTrimming();

/// <summary>

/// Text is trimmed at a character boundary. An ellipsis (...) is drawn in place of remaining text.

/// </summary>

public static TextTrimming CharacterEllipsis { get; } = new TextTrailingTrimming(DefaultEllipsisChar, false);

TomEdwardsEnscape · 2026-04-14T19:31:40Z

+                    ? UIImpactFeedbackGenerator.GetFeedbackGenerator(FeedbackToImpactStyle(feedback), _avaloniaView)
+                    : new UIImpactFeedbackGenerator(FeedbackToImpactStyle(feedback));
+                generator.Prepare();
+                generator.ImpactOccurred();


This method has an overload which accepts a position parameter. It would be trivial to accept an Avalonia position and provide it to iOS here.

avaloniaui-bot · 2026-04-17T11:41:09Z

You can test this PR using the following package version. 12.1.999-cibuild0064873-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

MrJul · 2026-05-07T09:32:03Z

Notes from the API review meeting:

Rename FeedbackEffect to FeedbackAction.
Make FeedbackAction a class (with an internal constructor for now, extensibility will happen later).
Add static FeedbackAction.Click and FeedbackAction.Hold members.
Change the documentation on Auto to make clear that it's platform-specific.

avaloniaui-bot · 2026-05-13T10:56:38Z

You can test this PR using the following package version. 12.1.999-cibuild0065351-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

emmauss · 2026-05-13T13:22:58Z

Updated API with review

avaloniaui-bot · 2026-05-13T13:57:10Z

You can test this PR using the following package version. 12.1.999-cibuild0065357-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

emmauss · 2026-06-04T14:15:02Z

Api change
IPlatformFeedback and PlatformFeedback moved to Avalonia.Controls to allow access in xaml.

avaloniaui-bot · 2026-06-04T14:45:32Z

You can test this PR using the following package version. 12.1.999-cibuild0066042-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2026-06-06T11:11:07Z

You can test this PR using the following package version. 12.1.999-cibuild0066115-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

MrJul

LGTM!

emmauss added 2 commits April 14, 2026 11:51

add platform feedback api for sound and haptic feedback

26045e5

add docs

ffd8945

emmauss requested review from MrJul and maxkatz6 April 14, 2026 12:17

make feedback extension public

a9cd2d4

MrJul added feature api-needs-review The PR adds new public APIs that should be reviewed. labels Apr 14, 2026

make IPlatformFeedback internal

27bb053

TomEdwardsEnscape reviewed Apr 14, 2026

View reviewed changes

emmauss added 2 commits April 17, 2026 11:05

update auto feedback doc

0677b93

cleanup up ios feedback impl

2916c62

MrJul added this to the 12.1 milestone May 7, 2026

MrJul added api-needs-changes The new public APIs need some changes. and removed api-needs-review The PR adds new public APIs that should be reviewed. labels May 7, 2026

Merge branch 'master' into platform_feedback_2

eaea1fe

update api

098a062

update docs

318ffca

MrJul added api-approved The new public APIs have been approved. and removed api-needs-changes The new public APIs need some changes. labels May 15, 2026

Merge branch 'master' into platform_feedback_2

bbfda76

MrJul requested changes Jun 4, 2026

View reviewed changes

addressed review

18a4769

Merge branch 'master' into platform_feedback_2

9a90dbe

MrJul approved these changes Jun 6, 2026

View reviewed changes

MrJul added this pull request to the merge queue Jun 6, 2026

Merged via the queue into master with commit 326badf Jun 6, 2026
11 checks passed

MrJul deleted the platform_feedback_2 branch June 6, 2026 12:28

		FeedbackEffect.Click => UIImpactFeedbackStyle.Light,
		FeedbackEffect.LongPress => UIImpactFeedbackStyle.Medium,

	public abstract class TextTrimming
	{
	internal const string DefaultEllipsisChar = "\u2026";

	/// <summary>
	/// Text is not trimmed.
	/// </summary>
	public static TextTrimming None { get; } = new TextNoneTrimming();

	/// <summary>
	/// Text is trimmed at a character boundary. An ellipsis (...) is drawn in place of remaining text.
	/// </summary>
	public static TextTrimming CharacterEllipsis { get; } = new TextTrailingTrimming(DefaultEllipsisChar, false);

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emmauss commented Apr 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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What does the pull request do?

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How was the solution implemented (if it's not obvious)?

Checklist

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Obsoletions / Deprecations

Fixed issues

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TomEdwardsEnscape Apr 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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emmauss commented Apr 14, 2026 •

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