Detect if iOS13 Dark Mode is enabled from Flutter/Dart

Question

I'm writing a Flutter app for Android and iOS which will change its style/theme based on iOS' Dark Mode status.

Is there currently anything like a MediaQuery.isDarkModeEnabled in Flutter?

There is a GitHub issue open here but the Flutter team must be overwhelmed in issues so I can't see this being implemented too soon.

I can use 'traitCollection.userInterfaceStyle' from iOS-specific code channels, but adding platform-specific code for Flutter/Dart apps is not something I'm experienced in. Currently working on this solution!

For example, someone could have a CupertinoPicker with adaptive colors:

CupertinoPicker(
    backgroundColor: isDarkModeEnabled ? Colors.black : Colors.white,
    children: items.map((thisItem) => Text(thisItem.name)).toList(),
    itemExtent: 32,
    onSelectedItemChanged: (newItem) {
        setState(() => this.item = items[newItem]);
    }
)

Answer 1

Here's how you can set different colors for light and dark mode, the app will automatically switch if the phone is set to dark mode or light mode.

MaterialApp(
  theme: ThemeData(
    brightness: Brightness.light,
    primaryColor: Colors.red,
  ),
  darkTheme: ThemeData(
    brightness: Brightness.dark,
    // additional settings go here
  ),
);

::Update::

You can also get the platform brightness (Brightness.light / Brightness.dark) using

WidgetsBinding.instance.window.platformBrightness

but you will have to use the WidgetsBindingObserver mixin and override the method below

@override
void didChangePlatformBrightness() {
    print(WidgetsBinding.instance.window.platformBrightness); // should print Brightness.light / Brightness.dark when you switch
    super.didChangePlatformBrightness(); // make sure you call this
}

see https://api.flutter.dev/flutter/widgets/WidgetsBindingObserver-class.html on how to use the mixin.