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fix(android): Avoid white flash on first frame #23593

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fix(android): Avoid white flash on first frame #23593

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6 changes: 6 additions & 0 deletions src/Uno.UI.Runtime.Skia.Android/ApplicationActivity.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,12 @@ public partial class ApplicationActivity : Controls.NativePage
private static bool _started;
private bool _isContentViewSet;

/// <summary>
/// Set by the GL thread after the first Skia frame has been rendered.
/// Used to keep the splash screen visible until pixels are ready.
/// </summary>
internal volatile bool FirstFrameRendered;

/// <summary>
/// The windows model implies only one managed activity.
/// </summary>
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8 changes: 8 additions & 0 deletions src/Uno.UI.Runtime.Skia.Android/Rendering/UnoSKCanvasView.cs
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Expand Up @@ -216,6 +216,14 @@ void IRenderer.OnDrawFrame(IGL10? gl)
// else : we already drew directly on the OpenGL-backed canvas

_context!.Flush();

if (!ApplicationActivity.Instance.FirstFrameRendered)

@github-actions github-actions Bot Jun 29, 2026

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The equivalent signaling is missing from UnoSKVulkanView.RenderFrame(). When FeatureConfiguration.Rendering.UseVulkanOnSkiaAndroid = true, the Vulkan renderer renders frames but never sets FirstFrameRendered = true, so OnPreDraw() keeps returning false and the splash screen is held forever.

The same block (set flag → post Invalidate) should be placed after _vulkanContext.RenderFrame(...) in UnoSKVulkanView.RenderFrame().

Fix this →

{
ApplicationActivity.Instance.FirstFrameRendered = true;
// Trigger OnPreDraw re-evaluation so the splash can dismiss once the first frame is on screen
ApplicationActivity.RelativeLayout?.Post(() =>
ApplicationActivity.RelativeLayout?.Invalidate());
}
}

void IRenderer.OnSurfaceChanged(IGL10? gl, int width, int height)
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3 changes: 2 additions & 1 deletion src/Uno.UI/UI/Xaml/Window/Native/NativeWindowWrapper.Android.cs
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Expand Up @@ -356,7 +356,8 @@ public ActivationPreDrawListener(IntPtr handle, JniHandleOwnership transfer)

public bool OnPreDraw()
{
if (_windowWrapper._contentViewAttachedToWindow)
if (_windowWrapper._contentViewAttachedToWindow
&& MUX.ApplicationActivity.Instance?.FirstFrameRendered == true)
{
_windowWrapper.RemovePreDrawListener();
return true;
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