Touch Improvements to TextBox by emmauss · Pull Request #20848 · AvaloniaUI/Avalonia

emmauss · 2026-03-09T08:52:02Z

What does the pull request do?

This PR adds a lot of improvements for touch controls for textbox. Pointer handling for Touch input has been reworked to feel more natural for touch based devices. New behavior closely matches Android's default touch behavior for text inputs.
The following changes and improvements have been made;

Scroll gesture has priority if its possible to scroll, otherwise moving the pointer across the textbox will move the caret position.
Holding on text will select the word and show selection handles.
Selection handles are larger.
Holding on a selected text region will show the textbox's context menu.
Selection handle control theme has been improved. Default theme uses combined geometry instead of a geometry group. PathIcon replaced with Image
An indicator element is now part of the selection handle control theme. Caret or selection position is now set based on the indicator position, and not the whole handle position.
SelectionHandles properly hide when out of bounds in the textbox. Behavior is more accurate now with the use of the presenter's transformed Clip region.
Text Selector Layer is now below the PopupOverlayLayer,allowing flyouts to show above the selection handles on embedded devices.
Scroll gesture has been updated to send gesture event only when the touch pointer actually moves.
Selection Handles properly detects and adapt to RTL text.

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

TextSelectionHandle control theme is updated.

Obsoletions / Deprecations

Fixed issues

avaloniaui-bot · 2026-03-09T09:29:34Z

You can test this PR using the following package version. 12.0.999-cibuild0063110-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2026-03-13T11:14:35Z

You can test this PR using the following package version. 12.0.999-cibuild0063361-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2026-03-13T13:48:44Z

You can test this PR using the following package version. 12.0.999-cibuild0063371-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2026-03-16T16:23:29Z

You can test this PR using the following package version. 12.0.999-cibuild0063515-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2026-03-17T12:46:21Z

You can test this PR using the following package version. 12.0.999-cibuild0063538-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2026-03-17T17:05:28Z

You can test this PR using the following package version. 12.0.999-cibuild0063549-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

…enu show behavior for selection handles

…erscrolled

avaloniaui-bot · 2026-03-18T13:13:54Z

You can test this PR using the following package version. 12.0.999-cibuild0063613-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

MrJul · 2026-03-19T10:22:03Z

src/Avalonia.Base/Input/GestureRecognizers/VelocityTracker.cs

+
+        public void Dispose()
+        {
+            _sinceLastSample.Stop();


Note: it's not technically required to Stop a Stopwatch, they don't do anything until measured.

MrJul · 2026-03-19T10:45:43Z

src/Avalonia.Controls/Primitives/TextSelectionHandle.cs

+
+        private void UpdateHandleClasses()
+        {
+            Classes.Remove("caret");


Standard classes should not be set directly, these are theme-specific. However, I see no issues in converting those to pseudo-classes instead.

MrJul · 2026-03-19T10:47:08Z

src/Avalonia.Controls/Primitives/TextSelectionCanvas.cs

-                flyout.Hide();
+            private List<Visual> _attachedVisuals = new List<Visual>();
+            private TextPresenter? _presenter;
+            private object _lock = new object();


The lock should not be needed. Everything here is dispatcher-bound, and accessing the controls from another thread is not supported.

MrJul · 2026-03-19T10:50:47Z

src/Avalonia.Controls/Primitives/TextSelectionCanvas.cs

+                    {
+                        if (visual is Layoutable layoutable)
+                        {
+                            layoutable.EffectiveViewportChanged += Visual_EffectiveViewportChanged;


Why do we need to listen to every parent? First, this is usually very brittle (it won't work correctly when the visual tree changes). Plus, if the viewport for the presenter itself hasn't actually changed, why is the invalidation needed?

MrJul · 2026-03-19T10:54:39Z

src/Avalonia.Controls/TextBox.cs

+        /// <summary>
+        /// The radius for touch input. Used to determine if selection should change from moving a touch pointer.
+        /// </summary>
+        private readonly static int s_touchRadius = (int)((AvaloniaLocator.Current?.GetService<IPlatformSettings>()?.GetTapSize(PointerType.Touch).Height ?? 10) / 2) + 5;


We should not access the locator in a static initializer. There is no guarantee that the locator will be correctly set, the runtime is free to run static initializers at any point. Consider making that lazy instead.

MrJul · 2026-03-19T11:01:37Z

src/Avalonia.Controls/Primitives/TextSelectionCanvas.cs

+        private static readonly bool s_shouldWrapAroundSelection;
+
        private const int ContextMenuPadding = 16;
+        private static bool s_isInTouchMode;


This is static but updated by instance specific code. Consider making it non-static.

MrJul · 2026-03-19T11:18:48Z

src/Avalonia.Controls/Presenters/ScrollContentPresenter.cs

+                if(!e.Handled)
+                {
+                    // Gesture may cause an overscroll so we mark the event as handled if it did.
+                    e.Handled = canXScroll || canYScroll;


I'm not sure I understand the logic here, won't that prevent scroll chaining in this case?

Confirmed while testing, scroll chaining does not work correctly anymore.

MrJul · 2026-03-19T11:24:31Z

There's a regression when a selection is active with the context menu open. Previously, double-tapping another word would select it in this case. Now, you need 3 taps instead (one to close the popup, then two for the normal double-tap selection to activate).

Please add a test for this once fixed.

MrJul · 2026-03-19T11:27:34Z

I've tested this with a touch screen, and overall, the changes are quite good :)
However, there are some regressions here.

We need more unit tests overall for this. This is not the easiest area to test, but we should be able to validate most of the behaviors added by this PR. They are too easy to break with future changes otherwise.

MrJul added the enhancement label Mar 9, 2026

emmauss force-pushed the textbox_touch_improvement branch from 344b20e to c07d2c3 Compare March 13, 2026 10:30

emmauss force-pushed the textbox_touch_improvement branch from bb3444b to 9823926 Compare March 15, 2026 22:17

emmauss added 17 commits March 18, 2026 11:44

wip touch improvement textbox

808d4fe

update text selection handle style

95994e6

change text selector layer z-index

f2f1635

fix build issues

51b298d

fix caret detection in touch mode

3d82482

added bottom padding to text handle

fcd4c19

add indicator visual to selection handler theme

0c7b71a

improve text selector indicator handling

10d4983

add support for wrap around in selection handles

9cb7a69

ensure textbox context menu is shown on hold

096cc8a

dampen scroll inertia

3a5eeff

increase default tap and double tap sizes for touch and pen

2a5c005

make textbox context menu horizontal in touch mode. improve context m…

20e7586

…enu show behavior for selection handles

detect overscroll in scroll presenter and handle scroll gesture if ov…

aeb77a9

…erscrolled

add rtl detection for selection handles

5e84dcf

improve context flyout behavior in handles

c9cec60

restore textbox page

45b9fe2

emmauss force-pushed the textbox_touch_improvement branch from 1523fc7 to 45b9fe2 Compare March 18, 2026 12:33

emmauss marked this pull request as ready for review March 18, 2026 12:37

emmauss changed the title ~~[WIP] Touch Improvements to TextBox~~ Touch Improvements to TextBox Mar 18, 2026

emmauss requested a review from MrJul March 18, 2026 12:41

MrJul reviewed Mar 19, 2026

View reviewed changes

Uh oh!

Conversation

emmauss commented Mar 9, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

What does the pull request do?

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

Breaking changes

Obsoletions / Deprecations

Fixed issues

Uh oh!

avaloniaui-bot commented Mar 9, 2026

Uh oh!

avaloniaui-bot commented Mar 13, 2026

Uh oh!

avaloniaui-bot commented Mar 13, 2026

Uh oh!

avaloniaui-bot commented Mar 16, 2026

Uh oh!

avaloniaui-bot commented Mar 17, 2026

Uh oh!

avaloniaui-bot commented Mar 17, 2026

Uh oh!

avaloniaui-bot commented Mar 18, 2026

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

MrJul commented Mar 19, 2026

Uh oh!

MrJul commented Mar 19, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

emmauss commented Mar 9, 2026 •

edited

Loading