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[.NET 10] [iOS] Fixed: Switch OffColor resets after minimizing and reopening the app #29771

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Merged
PureWeen merged 4 commits into from
Jul 1, 2025
Merged

[.NET 10] [iOS] Fixed: Switch OffColor resets after minimizing and reopening the app #29771

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c255539
Fixed UISwitch off-color issue
Tamilarasan-Paranthaman May 27, 2025
cf7679f
Added test sample
Tamilarasan-Paranthaman Jun 2, 2025
3287715
UISwitch OffColor changes
Tamilarasan-Paranthaman Jun 2, 2025
8f61454
Fixed Memory leak
Tamilarasan-Paranthaman Jun 5, 2025
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Binary file added ...Cases.Android.Tests/snapshots/android/VerifySwitchOffColorAfterReopeningApp.png
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49 changes: 49 additions & 0 deletions src/Controls/tests/TestCases.HostApp/Issues/Issue29768.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,49 @@
namespace Maui.Controls.Sample.Issues;

[Issue(IssueTracker.Github, 29768, "Switch OffColor not displayed after minimizing and reopening the app", PlatformAffected.iOS)]
public class Issue29768 : ContentPage
{
public Issue29768()
{

var defaultOffSwitch = new Switch
{
OffColor = Colors.Red,
VerticalOptions = LayoutOptions.Center,
HorizontalOptions = LayoutOptions.Center
};

var switchControl = new Switch
{
IsToggled = true,
OffColor = Colors.Red,
VerticalOptions = LayoutOptions.Center,
HorizontalOptions = LayoutOptions.Center
};

var button = new Button
{
Text = "Toggle Switch 2",
AutomationId = "toggleButton",
VerticalOptions = LayoutOptions.Center,
HorizontalOptions = LayoutOptions.Center
};

button.Clicked += (sender, e) =>
{
switchControl.IsToggled = !switchControl.IsToggled;
};

var verticalStackLayout = new VerticalStackLayout()
{
Spacing = 20,
Padding = new Thickness(20),
};

verticalStackLayout.Add(defaultOffSwitch);
verticalStackLayout.Add(switchControl);
verticalStackLayout.Add(button);

Content = verticalStackLayout;
}
}
28 changes: 28 additions & 0 deletions src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue29768.cs
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#if TEST_FAILS_ON_WINDOWS && TEST_FAILS_ON_CATALYST //The test fails on Windows and MacCatalyst because the BackgroundApp and ForegroundApp method, which is only supported on mobile platforms iOS and Android.
using NUnit.Framework;
using UITest.Appium;
using UITest.Core;

namespace Microsoft.Maui.TestCases.Tests.Issues;

public class Issue29768 : _IssuesUITest
{
public override string Issue => "Switch OffColor not displayed after minimizing and reopening the app";

public Issue29768(TestDevice device)
: base(device)
{ }

[Test]
[Category(UITestCategories.Switch)]
public void VerifySwitchOffColorAfterReopeningApp()
{
App.WaitForElement("toggleButton");
App.Tap("toggleButton");
App.BackgroundApp();
App.ForegroundApp();

VerifyScreenshot();
}
}
#endif
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63 changes: 63 additions & 0 deletions src/Core/src/Handlers/Switch/SwitchHandler.iOS.cs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,8 @@
using System;
using Microsoft.Maui.Graphics;
using System.Threading.Tasks;
using CoreFoundation;
using Foundation;
using ObjCRuntime;
using UIKit;
using RectangleF = CoreGraphics.CGRect;
Expand Down Expand Up @@ -60,21 +63,81 @@ class SwitchProxy

ISwitch? VirtualView => _virtualView is not null && _virtualView.TryGetTarget(out var v) ? v : null;

WeakReference<UISwitch>? _platformView;

UISwitch? PlatformView => _platformView is not null && _platformView.TryGetTarget(out var p) ? p : null;

NSObject? _willEnterForegroundObserver;
NSObject? _windowDidBecomeKeyObserver;

public void Connect(ISwitch virtualView, UISwitch platformView)
{
_virtualView = new(virtualView);
_platformView = new(platformView);
platformView.ValueChanged += OnControlValueChanged;

#if MACCATALYST
_windowDidBecomeKeyObserver = NSNotificationCenter.DefaultCenter.AddObserver(
new NSString("NSWindowDidBecomeKeyNotification"), _ =>
{
if (PlatformView is not null)
{
UpdateTrackOffColor(PlatformView);
}
});
#elif IOS
_willEnterForegroundObserver = NSNotificationCenter.DefaultCenter.AddObserver(
UIApplication.WillEnterForegroundNotification, _ =>
{
if (PlatformView is not null)
{
UpdateTrackOffColor(PlatformView);
}
});
#endif
}

// Ensures the Switch track "OFF" color is updated correctly after system-level UI resets.
// This is necessary because UIKit may re-apply default styles to internal views during certain lifecycle events,
// especially when the app enters the background and returns to the foreground.
void UpdateTrackOffColor(UISwitch platformView)
{
DispatchQueue.MainQueue.DispatchAsync(async () =>
{
if (!platformView.On)
{
await Task.Delay(10); // Small delay, necessary to allow UIKit to complete its internal layout and styling processes before re-applying the custom color
Comment on lines +103 to +109
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Copilot AI Jun 2, 2025

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[nitpick] Consider extracting the delay value '10' into a named constant to improve maintainability and clarify its purpose.

Suggested change
void UpdateTrackOffColor(UISwitch platformView)
{
DispatchQueue.MainQueue.DispatchAsync(async () =>
{
if (!platformView.On)
{
await Task.Delay(10); // Small delay, necessary to allow UIKit to complete its internal layout and styling processes before re-applying the custom color
const int UIKitStylingDelayMilliseconds = 10; // Small delay to allow UIKit to complete internal layout and styling processes
void UpdateTrackOffColor(UISwitch platformView)
{
DispatchQueue.MainQueue.DispatchAsync(async () =>
{
if (!platformView.On)
{
await Task.Delay(UIKitStylingDelayMilliseconds);

Copilot uses AI. Check for mistakes.

if (VirtualView is ISwitch view && view.TrackColor is not null)
{
platformView.UpdateTrackColor(view);
}
}
});
}

public void Disconnect(UISwitch platformView)
{
platformView.ValueChanged -= OnControlValueChanged;

if (_willEnterForegroundObserver is not null)
{
NSNotificationCenter.DefaultCenter.RemoveObserver(_willEnterForegroundObserver);
_willEnterForegroundObserver = null;
}
if (_windowDidBecomeKeyObserver is not null)
{
NSNotificationCenter.DefaultCenter.RemoveObserver(_windowDidBecomeKeyObserver);
_windowDidBecomeKeyObserver = null;
}
}

void OnControlValueChanged(object? sender, EventArgs e)
{
if (VirtualView is ISwitch virtualView && sender is UISwitch platformView && virtualView.IsOn != platformView.On)
{
virtualView.IsOn = platformView.On;
}
}
}
}
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