⚽ Live Match: AvaloniaUI/Avalonia/pull/

emmauss · 2024-07-16T14:26:40Z

What does the pull request do?

Changes ITopLevelImpl.SetFrameThemeVariant to receive nullable PlatformThemeVariant. This is to enable ThemeVariant.Default to be interpreted as System default on the platform level. On Android, this allows detecting theme changes triggered by the OS.

What is the current behavior?

Android seems to have a weird behavior concerning theme "ownership".
A simple app(native android in this case) that doesn't change theme dynamically will always follow System theme. In this case, if the app is handling uiMode configuration changes to detect theme, both Activity.OnConfigurationChanged and View.OnConfigurationChanged will be called with the new ui mode.

If the app sets their app theme with AppCompatDelegate.DefaultNightMode to NightModeYes/No, the system no longer manages theming for the app, and only Activity.OnConfigurationChanged will be called for the app to detect system theme change.
In avalonia, we rely on View.OnConfigurationChanged to detect system theme change, but since we enforce ThemeVariant when the app launches, we no longer receive uiMode notifications through View.OnConfigurationChanged. We can listen to it on Activity level, but that wouldn't work when an avalonia view is embedded in an Activity we don't control.

Currently, we have 2 PlatformThemeVariants, Dark and Light. There is no Default or System variant that would reset the app theme to the system one. Android saves the last NightMode for the app and applies it when the Activity is created, unless the app is newly installed, the RequestedThemeVariant usually set in App.xaml. This is due to requesting the systems/app theme accents here;

Avalonia/src/Android/Avalonia.Android/AvaloniaView.cs

Line 34 in 9c6a2c9

OnConfigurationChanged();

which will also forward the saved NightMode to the app. We need the system accents, so we can't skip sending the current configuration.

What is the updated/expected behavior with this PR?

Setting App.RequestedThemeVariant to ThemeVariant.Default will set the app theme to the System on android, allowing app theme to change dynamically.

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

Fixes #16241

…roid

… Default

maxkatz6 · 2024-07-17T21:32:40Z

+            AppCompatDelegate.DefaultNightMode = themeVariant == null ? AppCompatDelegate.ModeNightFollowSystem :
+                themeVariant == PlatformThemeVariant.Light ? AppCompatDelegate.ModeNightNo : AppCompatDelegate.ModeNightYes;
+
+            if (AppCompatDelegate.DefaultNightMode == AppCompatDelegate.ModeNightFollowSystem && _view.Context is { } context


Can you add some brief comments on this part of the code? Just so reasoning will be kept in the code as well.

maxkatz6 · 2024-07-17T21:33:42Z


+        static Application()
+        {
+            RequestedThemeVariantProperty.OverrideDefaultValue<Application>(ThemeVariant.Default);


nit: RequestedThemeVariantProperty should already have Default as a default value.

Currently, it doesn't. AddOwner doesn't inherit the default value of the property.

Should be removed once #21624 is merged.

maxkatz6 · 2024-07-17T21:36:31Z

+            if ((RequestedThemeVariant ?? ThemeVariant.Default) == ThemeVariant.Default)
+                SetCurrentValue(ActualThemeVariantProperty, (ThemeVariant)e.ThemeVariant);


With this change, we break theme switching (at least on desktop), when:

Apps opens with default Dark variant.

User switches to non-default Dark variant.

OS changes global theme variant to Light variant. - at this point Application won't receive any changes about system theme because of this condition.

User switches back to Default variant. But app won't be changed, because previous OnColorValuesChanged was ignored.

We probably need to save latest value in the field. And use it when user changes to Default.

@emmauss I pushed a commit that changes 372 line. When user switches to the Default variant - we now read GetColorValues(). Works on Windows well.

Let me know if it still works on android as expected.

The changes on 372 prevent Default from ever being sent to the toplevel impl, which we need on the android side.

@emmauss I pushed a commit that changes 372 line. When user switches to the Default variant - we now read GetColorValues(). Works on Windows well.

Let me know if it still works on android as expected.

It doesn't really work. Since only Light or Dark is ever sent to the OS with your change, the OS never switches to FollowSystem.
We could pass both Actual variant and Requested variant. Requested for the OS to know what the app want, and Actual for the OS to update the system bars and nav bar

Should be fixed now

Note: the exact scenario reported by Max above still fails on X11:
(Default Dark => Light => Default doesn't switch back to Dark).

maxkatz6 · 2024-07-17T21:38:24Z


+        static ThemeVariantScope()
+        {
+            RequestedThemeVariantProperty.OverrideDefaultValue<ThemeVariantScope>(ThemeVariant.Default);


nit: again, it should be Default by default already. See https://github.com/AvaloniaUI/Avalonia/blob/master/src/Avalonia.Base/Styling/ThemeVariant.cs#L29-L31

Same issue as Application

Should be removed once #21624 is merged.

maxkatz6 · 2024-07-17T21:49:12Z

        private void GlobalActualThemeVariantChanged(object? sender, EventArgs e)
        {
-            SetValue(ActualThemeVariantProperty, ((IThemeVariantHost)sender!).ActualThemeVariant, BindingPriority.Template);
+            SetCurrentValue(ActualThemeVariantProperty, ((IThemeVariantHost)sender!).ActualThemeVariant);


It seems to break when:

User has Application.RequestedThemeVariant = Light

User changes Window.RequestedThemeVariant = Dark

User changes to Application.RequestedThemeVariant to Dark and then to Light again - Window now Light again, because SetCurrentValue has overridden value.

BindingPriority.Template is a lower priority than CurrentValue, so it was used to keep global variant lower priority than variant set by user on TopLevel directly.

Should be fixed now

avaloniaui-bot · 2024-07-17T22:04:54Z

You can test this PR using the following package version. 11.2.999-cibuild0050252-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2024-08-01T23:59:18Z

You can test this PR using the following package version. 11.2.999-cibuild0050847-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2024-09-02T15:28:25Z

You can test this PR using the following package version. 11.2.999-cibuild0051604-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

avaloniaui-bot · 2025-02-20T15:00:31Z

You can test this PR using the following package version. 11.3.999-cibuild0055013-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

MrJul · 2025-07-31T14:17:45Z

There are still issues with this PR, we need more time to fix it for all platforms. I'm marking it as a draft for now since it's not ready in its current state.

emmauss · 2026-06-19T07:26:39Z

Rebased

avaloniaui-bot · 2026-06-19T08:16:05Z

You can test this PR using the following package version. 12.1.999-cibuild0066652-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

MrJul

I haven't retested all platforms yet, but switching back to the default theme is broken on at least X11.

…-night-mode

avaloniaui-bot · 2026-06-23T13:48:36Z

You can test this PR using the following package version. 12.1.999-cibuild0066820-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

MrJul

All platforms are now working as expected.
LGTM!

avaloniaui-bot · 2026-06-24T11:01:12Z

You can test this PR using the following package version. 12.1.999-cibuild0066866-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

emmauss force-pushed the android-auto-detect-night-mode branch from c790620 to a5b7801 Compare July 16, 2024 14:26

maxkatz6 added bug os-android backport-candidate-11.1.x labels Jul 17, 2024

maxkatz6 reviewed Jul 17, 2024

View reviewed changes

Comment thread src/Avalonia.Base/Platform/PlatformColorValues.cs Resolved

emmauss force-pushed the android-auto-detect-night-mode branch from a5b7801 to 8f7eb32 Compare July 17, 2024 12:15

allow setting ThemeVariant to Default to reset theme to system on and…

91348e2

…roid

emmauss force-pushed the android-auto-detect-night-mode branch from 8f7eb32 to 91348e2 Compare July 17, 2024 13:05

emmauss and others added 2 commits July 17, 2024 16:56

update api diff

5f26382

Fix theme variant not being applied when switching from Light/Dark to…

37d4fca

… Default

maxkatz6 reviewed Jul 17, 2024

View reviewed changes

Comment thread api/Avalonia.nupkg.xml Resolved

maxkatz6 reviewed Jul 17, 2024

View reviewed changes

Comment thread src/Avalonia.Base/Styling/ThemeVariant.cs Resolved

maxkatz6 reviewed Jul 17, 2024

View reviewed changes

Comment thread src/Avalonia.Native/WindowImplBase.cs Resolved

Use IPlatformSettings as a fallback in macOS SetFrameThemeVariant

4c64635

maxkatz6 reviewed Jul 17, 2024

View reviewed changes

Merge branch 'master' into android-auto-detect-night-mode

9a2db1e

emmauss added 3 commits September 2, 2024 08:43

Merge branch 'master' into android-auto-detect-night-mode

cc657b2

fix nullable check in android avaloniaview

c3daac9

fix SetFrameThemeVariant api suppression

40500db

emmauss force-pushed the android-auto-detect-night-mode branch from 3f31cdc to 40500db Compare September 2, 2024 15:05

Merge branch 'master' into android-auto-detect-night-mode

968eb94

MrJul mentioned this pull request Jun 22, 2026

Fix RequestedThemeVariant default value #21624

Merged

MrJul requested changes Jun 22, 2026

View reviewed changes

fix default theme selection on desktop

22067ae

emmauss force-pushed the android-auto-detect-night-mode branch from 9160440 to 22067ae Compare June 23, 2026 12:03

emmauss added 3 commits June 23, 2026 12:13

add missing changes

c43aabf

Merge remote-tracking branch 'origin/master' into android-auto-detect…

44bb746

…-night-mode

fix wayland default theme detection

3df12fa

MrJul reviewed Jun 23, 2026

View reviewed changes

Comment thread src/Avalonia.FreeDesktop/DBusPlatformSettings.cs Resolved

emmauss added 2 commits June 23, 2026 12:55

fix browser theme detection

7fb11c5

removed redundant overrides

70da60b

MrJul added 3 commits June 24, 2026 12:16

Fix macOS default theme detection

b945c72

Fix iOS default theme detection

4e3b9d3

Avoid async void

a4e7ded

MrJul approved these changes Jun 24, 2026

View reviewed changes

MrJul enabled auto-merge June 24, 2026 10:40

MrJul added this pull request to the merge queue Jun 24, 2026

github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Jun 24, 2026

MrJul added this pull request to the merge queue Jun 24, 2026

Merged via the queue into master with commit 7846c5c Jun 24, 2026
11 checks passed

MrJul deleted the android-auto-detect-night-mode branch June 24, 2026 13:00

MrJul mentioned this pull request Jul 9, 2026

Fix AvaloniaView double root creation on Android #21738

Merged

maxkatz6 mentioned this pull request Jul 16, 2026

[Bug]: DevTools will crash application when switching Application.RequestedThemeVariant AvaloniaUI/AvaloniaPro#146

Open

pos777 mentioned this pull request Jul 22, 2026

DBusPlatformSettings: NullReferenceException occurs if there is no DBusHelper.DefaultConnection #21821

Closed

TomEdwardsEnscape mentioned this pull request Aug 3, 2026

Win32: ColorValuesChanged is raised on every TopLevel construction since 12.1.0, causing UI stalls proportional to visual-tree size #21897

Closed

MrJul mentioned this pull request Aug 5, 2026

Ensure that ActualThemeVariant always has a proper value #21930

Merged

		if ((RequestedThemeVariant ?? ThemeVariant.Default) == ThemeVariant.Default)
		SetCurrentValue(ActualThemeVariantProperty, (ThemeVariant)e.ThemeVariant);

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emmauss commented Jul 16, 2024 • 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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emmauss commented Jul 16, 2024 •

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