Is it possible to opt-out of dark mode on iOS 13?

Question

A large part of my app consists of web views to provide functionality not yet available through native implementations. The web team has no plans to implement a dark theme for the website. As such, my app will look a bit half/half with Dark Mode support on iOS 13.

Is it possible to opt out of Dark Mode support such that our app always shows light mode to match the website theme?

Answer 1

According to Apple's "Implementing Dark Mode on iOS" Session (https://developer.apple.com/videos/play/wwdc2019/214/ starting at 31:13) it is possible to set overrideUserInterfaceStyle to UIUserInterfaceStyleLight or UIUserInterfaceStyleDark on any view controller or view, which will the be used in the traitCollection for any subview or view controller.

As already mentioned by SeanR, you can set UIUserInterfaceStyle to Light or Dark in you app's plist file to change this for your whole app.

Answer 2

I think I've found the solution. I initially pieced it together from UIUserInterfaceStyle - Information Property List and UIUserInterfaceStyle - UIKit, but have now found it actually documented at Choosing a specific interface style for your iOS app.

In your info.plist, set UIUserInterfaceStyle (User Interface Style) to 1 (UIUserInterfaceStyle.light).

EDIT: As per dorbeetle's answer, a more appropriate setting for UIUserInterfaceStyle may be Light.

Answer 3

The answer above works if you want to opt out the whole app. If you are working on the lib that has UI, and you don't have luxury of editing .plist, you can do it via code too.

If you are compiling against iOS 13 SDK, you can simply use following code:

Swift:

if #available(iOS 13.0, *) {
    self.overrideUserInterfaceStyle = .light
}

Obj-C:

if (@available(iOS 13.0, *)) {
    self.overrideUserInterfaceStyle = UIUserInterfaceStyleLight;
}

HOWEVER, if you want your code to compile against iOS 12 SDK too (which right now is still the latest stable SDK), you should resort to using selectors. Code with selectors:

Swift (XCode will show warnings for this code, but that's the only way to do it for now as property does not exist in SDK 12 therefore won't compile):

if #available(iOS 13.0, *) {
    if self.responds(to: Selector("overrideUserInterfaceStyle")) {
        self.setValue(UIUserInterfaceStyle.light.rawValue, forKey: "overrideUserInterfaceStyle")
    }
}

Obj-C:

if (@available(iOS 13.0, *)) {
    if ([self respondsToSelector:NSSelectorFromString(@"overrideUserInterfaceStyle")]) {
        [self setValue:@(UIUserInterfaceStyleLight) forKey:@"overrideUserInterfaceStyle"];
    }
}