Appearance addChangeListener handler is called when app goes to background with wrong color scheme

[rosskhanas]

Description

A handler function of Appearance.addChangeListener is triggered when the app goes to the background. It also has a wrong colorScheme value.

React Native version:

System:
    OS: macOS 10.15.1
    CPU: (4) x64 Intel(R) Core(TM) i7-5557U CPU @ 3.10GHz
    Memory: 92.24 MB / 16.00 GB
    Shell: 5.7.1 - /bin/zsh
  Binaries:
    Node: 10.13.0 - /usr/local/bin/node
    Yarn: 1.12.1 - /usr/local/bin/yarn
    npm: 6.9.0 - /usr/local/bin/npm
    Watchman: Not Found
  Managers:
    CocoaPods: 1.8.4 - /usr/local/bin/pod
  SDKs:
    iOS SDK:
      Platforms: iOS 13.2, DriverKit 19.0, macOS 10.15, tvOS 13.2, watchOS 6.1
    Android SDK:
      API Levels: 23, 25, 26, 27, 28, 29
      Build Tools: 27.0.3, 28.0.2, 28.0.3, 29.0.2
      System Images: android-23 | Google APIs Intel x86 Atom, android-27 | Google Play Intel x86 Atom, android-28 | Google APIs Intel x86 Atom, android-28 | Google Play Intel x86 Atom, android-29 | Google APIs Intel x86 Atom
      Android NDK: Not Found
  IDEs:
    Android Studio: 3.5 AI-191.8026.42.35.5791312
    Xcode: 11.2.1/11B500 - /usr/bin/xcodebuild
  Languages:
    Python: 2.7.15 - /usr/local/bin/python
  npmPackages:
    @react-native-community/cli: Not Found
    react: 16.11.0 => 16.11.0 
    react-native: 0.62.1 => 0.62.1 
  npmGlobalPackages:
    *react-native*: Not Found

Steps To Reproduce

1. Register Appearance.addChangeListener at the root of the app (I use it with react-native-navigation).

Appearance.addChangeListener(({ colorScheme }) => {
  console.log(colorScheme);
});

2. Move the app to the background.

Expected Results

No theme changed.

[github-actions]

⚠️	Missing Reproducible Example
ℹ️	It looks like your issue is missing a reproducible example. Please provide a Snack or a repository that demonstrates the issue you are reporting in a minimal, complete, and reproducible manner.

[rosskhanas]

Here is a repo: https://github.com/rosskhanas/react-native-appearance-bug

Once the app goes to the background it logs 2 rows - 2 different values to the console - light, and dark.

[adechassey]

+1, having the same issue!

[stale]

Hey there, it looks like there has been no activity on this issue recently. Has the issue been fixed, or does it still require the community's attention? This issue may be closed if no further activity occurs. You may also label this issue as a "Discussion" or add it to the "Backlog" and I will leave it open. Thank you for your contributions.

[rosskhanas]

Not stale

[manuhook]

The problem is on iOS only.
When backgrounding the app, perhaps due to a bug on iOS 13 the user interface style changes to the opposite color scheme and then back to the current color scheme immediately afterwards. The best solution is to debounce the notification calls by 10ms like they did on react-native-appearance.

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0,01 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
    [[NSNotificationCenter defaultCenter] postNotificationName:RCTUserInterfaceStyleDidChangeNotification
                                                        object:self
                                                      userInfo:@{
                                                        RCTUserInterfaceStyleDidChangeNotificationTraitCollectionKey: self.traitCollection,
                                                      }];
  });

[david-cako]

Definitely still seeing this. Moved to expo/react-native-appearance for now.

[justincbeck]

With this code in my App.js, I am seeing the extra calls but not the flash back and forth between themes:

  const systemScheme = useColorScheme();
  const themeObject = systemScheme === 'light' ? light : dark;

  const toggleTheme = useCallback((colorScheme) => {
    const statusBarTheme = colorScheme === 'light' ? 'dark' : 'light';
    StatusBar.setBarStyle(`${statusBarTheme}-content`);
  }, []);

  useEffect(() => {
    Appearance.addChangeListener(({ colorScheme }) => {
      toggleTheme(colorScheme);
    });
    return () => {
      Appearance.removeChangeListener();
    };
  }, [toggleTheme]);

Hope that helps someone.

[Macrow]

I have the same problem on iOS, and I found expo/react-native-appearance have this issue too, I don't know if it was my mistake.

I fix it by Lodash temporary, I don't find a better way.

import _ from 'lodash';

useEffect(() => {
    const handleColorModeChange = async (preferences: Appearance.AppearancePreferences) => {
      console.log(preferences.colorScheme);
      // do your job ....
    };

    // delay 1 second to handle change
    Appearance.addChangeListener(_.throttle(handleColorModeChange, 1000, {
      leading: false,
      trailing: true
    }));

    return () => {
      Appearance.removeChangeListener(handleColorModeChange);
    };
  }, []);

[jasonaibrahim]

@Macrow your workaround helped. thank you

here it is as a hook to use in lieu of the rn useColorScheme hook. I also used setTimeout instead of throttle

import { Appearance, ColorSchemeName } from 'react-native';
import { useEffect, useRef, useState } from 'react';

export default function useColorScheme(delay = 500): NonNullable<ColorSchemeName> {
  const [colorScheme, setColorScheme] = useState(Appearance.getColorScheme());

  let timeout = useRef<NodeJS.Timeout | null>(null).current;

  useEffect(() => {
    Appearance.addChangeListener(onColorSchemeChange);

    return () => {
      resetCurrentTimeout();
      Appearance.removeChangeListener(onColorSchemeChange);
    };
  }, []);

  function onColorSchemeChange(preferences: Appearance.AppearancePreferences) {
    resetCurrentTimeout();

    timeout = setTimeout(() => {
      setColorScheme(preferences.colorScheme);
    }, delay);
  }

  function resetCurrentTimeout() {
    if (timeout) {
      clearTimeout(timeout);
    }
  }

  return colorScheme as NonNullable<ColorSchemeName>;
}

[CalebLovell]

Thanks @jasonaibrahim, I really didn't want to fool with this nonsense today. That makes it easy! 🙌

[jgo80]

Dump question, isn't it the easiest way to just call Appearance.getColorScheme() when the Listener fires? Works well for me without a cumbersome timer...

  const initAppearanceListener = () => {
    const listener: Appearance.AppearanceListener = ({ colorScheme } /* <-- ignore */) => {
      setColorScheme(Appearance.getColorScheme());
    };
    Appearance.addChangeListener(listener);
    return () => Appearance.removeChangeListener(listener);
  };

[Codelica]

@mrsimply you could, although I'm not sure what ignoring the colorScheme that's sent in really buys. Are you not seeing the listener fired twice with the wrong and then correct color scheme when the app is backgrounded?

I definitely do, so for now have just been ignoring the colorScheme listener calls when AppState says things are backgrounded.

[marcshilling]

Dump question, isn't it the easiest way to just call Appearance.getColorScheme() when the Listener fires? Works well for me without a cumbersome timer...

This worked for me, just ignoring the argument passed into the function

[michael2h4ng]

Here is a repo: https://github.com/rosskhanas/react-native-appearance-bug

Once the app goes to the background it logs 2 rows - 2 different values to the console - light, and dark.

I believe this is a feature on iOS 13 and above. It does this to take screenshots of the app for the App Switcher in case color scheme changes.

[outaTiME]

Dump question, isn't it the easiest way to just call Appearance.getColorScheme() when the Listener fires? Works well for me without a cumbersome timer...

  const initAppearanceListener = () => {
    const listener: Appearance.AppearanceListener = ({ colorScheme } /* <-- ignore */) => {
      setColorScheme(Appearance.getColorScheme());
    };
    Appearance.addChangeListener(listener);
    return () => Appearance.removeChangeListener(listener);
  };

Sorry, but as I say in the following link, it keeps happening very randomly with your workaround:

expo/expo#10815 (comment)

[komik966]

@zhumingcheng697 Have you tried to change OS color scheme via OS settings like shown on the recording in this comment mattermost/mattermost-mobile#5635 (review) ? It should also work perfectly.

[zhumingcheng697]

@komik966 Very glad that you asked! I thought it would, and it almost did, but there were two minor cases where the DynamicColorIOS colors were not updated correctly in the app switcher, specifically:

1. the custom border color I set for React Navigation header and tab bar
2. the custom border color I set for NativeBase Input and Select components every single NativeBase component

Not sure if I suspect that it might be because borderColors are being handled differently, since every instance of borderColor is not updating correctly but all my other colors and backgroundColors are being handled perfectly fine in both React Navigation and NativeBase.

App.Switcher.MP4

At the end, I chose to use the same color for the borders under both light and dark mode to avoid the flashing when going to the app switcher.

[noumantahir]

https://reactnative.dev/docs/usecolorscheme This hook could help someone.

Experiencing flashing with useColorScheme hook as well..

"react-native": "0.70.4",

[JHPG]

Try to use Appearance.getColorScheme() instead.

https://reactnative.dev/docs/appearance

[s123121]

2 years passed and this bug still haunted me every other day

[efstathiosntonas]

this worked for me:

import { useEffect, useState } from "react";
import { Appearance, ColorSchemeName } from "react-native";
import debounce from "lodash/debounce";

// This hook is from https://github.com/facebook/react-native/issues/28525
export function useColorScheme(): NonNullable<ColorSchemeName> {
  const [colorScheme, setColorScheme] = useState(Appearance.getColorScheme());

  const initAppearanceListener = () => {
    const listener: Appearance.AppearanceListener = debounce(
      () => {
        setColorScheme(Appearance.getColorScheme());
      },
      200,
      { leading: false, trailing: true }
    );
    const changeListener = Appearance.addChangeListener(listener);
    return () => changeListener.remove();
  };

  useEffect(() => {
    initAppearanceListener();
  }, []);

  return colorScheme as NonNullable<ColorSchemeName>;
}

[imransilvake]

I solved it finally using AppState 🎉.
Note: I am using NativeWind. Please adjust the code according to your needs.

import { useColorScheme as useNativeWindColorScheme } from 'nativewind';
import { AppState, useColorScheme } from 'react-native';

const Root = () => {
	const currentColorScheme = useColorScheme();
	const { colorScheme, setColorScheme } = useNativeWindColorScheme();
	const isDarkTheme = colorScheme === GlobalSchemeEnum.DARK;
	const LightTheme = { dark: !isDarkTheme, colors: ThemeNavigationLightColors };
	const DarkTheme = { dark: isDarkTheme, colors: ThemeNavigationDarkColors };
	const theme = isDarkTheme ? DarkTheme : LightTheme;

	useEffect(() => {
		const subscription = AppState.addEventListener('change', (state) => {
			const isActive = state === 'active';
			if (!isActive) return;
			currentColorScheme && setColorScheme(currentColorScheme);
		});
		return () => subscription.remove();
	}, [colorScheme, setColorScheme, currentColorScheme]);

	{/* Navigation */}
	<NavigationContainer theme={theme}>
		<App />		
	</NavigationContainer>
};

AppRegistry.registerComponent(appName, () => Root);

Let me know if it doesn't work!

[blueberry6401]

2023, latest version, and this bug is still there.
My (workaround) solution is using lodash.debounce with leading = false.

[russeg]

wow how is this bug still not fixed. i remember having this same bug in flutter, but there the issue was tagged, reproed, triaged, and fixed in less than 12 hours.

anyway, thanks for the many and varied workarounds.

[jrhager84]

It's kind of sad how many persistent bugs just sit for years without much notice. Oh well... :/

[bitcrumb]

Imho, you could argue if it is a bug or not, since the behavior follows the underlying iOS framework behavior. However, it does feel as unwanted behavior.

That being said, it is easily remediated by just checking if the change happens in the foreground. In our codebase we just query the current AppState in the listener and only if it is equal to "foreground" we act upon it.

[jrhager84]

Imho, you could argue if it is a bug or not, since the behavior follows the underlying iOS framework behavior. However, it does feel as unwanted behavior.

That being said, it is easily remediated by just checking if the change happens in the foreground. In our codebase we just query the current AppState in the listener and only if it is equal to "foreground" we act upon it.

But if someone changes their dark mode in the settings while the app is in background mode, it won't track.

At least the last time I tried it wouldn't work.

I would love to see your implementation if you wouldn't mind.

[komik966]

Hi all, did you try this solution #28525 (comment) ? This seems the best solution which also updates app screenshot in the app switcher.

[jrhager84]

Hi all, did you try this solution #28525 (comment) ? This seems the best solution which also updates app screenshot in the app switcher.

I'm using react navigation (which they indicated was incompatible)

[Codelica]

Maybe I'm missing something here, but I just ignore listener calls when the app is backgrounded and manually check the current system theme when the app becomes active. I guess that won't cover the screenshot change in the app switcher until they re-launch the app, but ¯(ツ)/¯

[vasylnahuliak]

My workaround (https://github.com/ds300/patch-package use for applying changes)

diff --git a/node_modules/react-native/React/CoreModules/RCTAppearance.mm b/node_modules/react-native/React/CoreModules/RCTAppearance.mm
index 17535a9..e7fd131 100644
--- a/node_modules/react-native/React/CoreModules/RCTAppearance.mm
+++ b/node_modules/react-native/React/CoreModules/RCTAppearance.mm
@@ -106,9 +106,8 @@ RCT_EXPORT_METHOD(setColorScheme : (NSString *)style)
 
 RCT_EXPORT_SYNCHRONOUS_TYPED_METHOD(NSString *, getColorScheme)
 {
-  if (_currentColorScheme == nil) {
-    _currentColorScheme = RCTColorSchemePreference(nil);
-  }
+  _currentColorScheme = RCTColorSchemePreference(nil);
+
   return _currentColorScheme;
 }

⚠️ PAY ATTENTION: These changes can create new bugs!

react-native+0.72.3.patch

[fabOnReact]

how many devs experience this issue in the latest version of react-native?
The implementation of the method changed since this issue was opened.

[junebugfix]

This was fixed for me on 0.73.5! 🎉

[outaTiME]

This was fixed for me on 0.73.5! 🎉

I'm using version 0.73.4 (and finally so far) it seems to be working properly too 🙌

[kelset]

that's great! Given that there are a couple of reports of the issue being fixed let's close this. If you have any further issues I would recommend opening a new issue with a proper repro.