Android - How to detect if night mode is on when using AppCompatDelegate.MODE_NIGHT_AUTO

Question

I'm using Androids built in day/night mode functionality and I'd like to add an option to my app for AppCompatDelegate.MODE_NIGHT_AUTO

I'm having a problem though because my app requires certain things to be colored programmatically, and I can't figure out how to check if the app considers itself in night or day mode. Without that, I can't set a flag to choose the right colors.

Calling AppCompatDelegate.getDefaultNightMode() just returns AppCompatDelegate.MODE_NIGHT_AUTO which is useless.

I don't see anything else that would tell me, but there must be something?

Answer 1

int nightModeFlags =
    getContext().getResources().getConfiguration().uiMode &
    Configuration.UI_MODE_NIGHT_MASK;
switch (nightModeFlags) {
    case Configuration.UI_MODE_NIGHT_YES:
         doStuff();
         break;

    case Configuration.UI_MODE_NIGHT_NO:
         doStuff();
         break;

    case Configuration.UI_MODE_NIGHT_UNDEFINED:
         doStuff();
         break;
}

Answer 2

to check for night mode you can do as below:

public boolean isNightMode(Context context) {
    int nightModeFlags = context.getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK;
    return nightModeFlags == Configuration.UI_MODE_NIGHT_YES;
}

Answer 3

For Xamarin.Android

if (Build.VERSION.SdkInt >= BuildVersionCodes.Froyo)
{
    var uiModeFlags = Application.Context.Resources.Configuration.UiMode & UiMode.NightMask;
    switch (uiModeFlags)
    {
        case UiMode.NightYes:
            // dark mode
            break;
        case UiMode.NightNo:
            // default mode
            break;
        default:
            // default mode
            break;
    }
}
else
{
// default mode
}

Answer 4

I had problems with my UI tests, when try to get current theme in every answer code. It every time return the same value.

So I create static variable in application class and get theme for UI tests throw it:

@Theme
fun Context.getAppTheme(): Int? {
    val theme = when (resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK) {
        Configuration.UI_MODE_NIGHT_NO -> Theme.LIGHT
        Configuration.UI_MODE_NIGHT_YES -> Theme.DARK
        else -> null
    }

    Application.theme = theme

    return theme
}

In Application class:

companion object {
    @Theme
    @RunNone var theme: Int? = null
}

May be it will be usefull for someone!

Answer 5

Kotlin Version :->

fun isDarkMode(context: Context): Boolean {
    val darkModeFlag = context.resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK
    return darkModeFlag == Configuration.UI_MODE_NIGHT_YES
}

Answer 6

From Android Version R (30) there is provided a value in context.resources.configuration.isNightModeActive.

So you don't need to mask anymore.

Example in onConfigurationChanged:

private var _isNightModeActive: Boolean = false

override fun onConfigurationChanged(newConfig: Configuration) {
        _isNightModeActive =
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
                _resources.configuration.isNightModeActive
            } else {
                newConfig.uiMode and
                        Configuration.UI_MODE_NIGHT_MASK ==
                        Configuration.UI_MODE_NIGHT_YES
            }
    }

Answer 7

A very simple solution is to add a string resource like this.

res/values/strings.xml

<string name="mode">Day</string>

res/values-night/strings.xml

<string name="mode">Night</string>

And then wherever you need to check it:

if (resources.getString(R.string.mode) == "Day") {
    // Do Day stuff here
} else {
    // Do night stuff here
}

But you CAN NOT call this before super.onCreate() in an activity's life-cycle. It will always return "Day" before onCreate.

Answer 8

Maybe just a property that will actually tell you if you have Dark Mode ?

val Context.isDarkMode
    get() = if (getDefaultNightMode() == MODE_NIGHT_FOLLOW_SYSTEM)
        resources.configuration.uiMode and UI_MODE_NIGHT_MASK == UI_MODE_NIGHT_YES
    else getDefaultNightMode() == MODE_NIGHT_YES

Answer 9

I found nothing of this to be working after changing the the app to dark theme with

AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);

Is there any way to know the system setting after changing the app with this method?
Thanks,
FF

Answer 10

If you are kotlin developer then you can use below code to judge dark mode.

when (context.resources?.configuration?.uiMode?.and(Configuration.UI_MODE_NIGHT_MASK)) {
    Configuration.UI_MODE_NIGHT_YES -> {}
    Configuration.UI_MODE_NIGHT_NO -> {}
    Configuration.UI_MODE_NIGHT_UNDEFINED -> {}
}

For more about dark theme mode

https://github.com/android/user-interface-samples/tree/main/DarkTheme

Answer 11

The idea of using the flag resources.configuration.isNightModeActive is same as @Carsten. I would suggest a simple code structure.

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R &&
        resources.configuration.isNightModeActive) {

    // code for night mode

} else {

    // code for day mode (or less than API-30)

}

Answer 12

The bitwise operator in Java (which is used in @ephemient 's answer) is different in kotlin so the code might not be easily convertible for beginners. Here is the kotlin version just in case someone needs it:

    private fun isUsingNightModeResources(): Boolean {
        return when (resources.configuration.uiMode and 
Configuration.UI_MODE_NIGHT_MASK) {
            Configuration.UI_MODE_NIGHT_YES -> true
            Configuration.UI_MODE_NIGHT_NO -> false
            Configuration.UI_MODE_NIGHT_UNDEFINED -> false
            else -> false
    }
}