How can I check whether dark mode is enabled in iOS/iPadOS?

Question

Starting from iOS/iPadOS 13, a dark user interface style is available, similar to the dark mode introduced in macOS Mojave. How can I check whether the user has enabled the system-wide dark mode?

Answer 1

SwiftUI

With the \.colorScheme key of an Environment variable:

struct ContentView: View {
    @Environment(\.colorScheme) var colorScheme

    var body: some View {
        Text(colorScheme == .dark ? "In dark mode" : "In light mode")
    }
}

Also, it automatically updates on the change of the environment color scheme.

---

UIKit

To check the current, all object those conform to UITraitEnvironment protocol, including all UIView subclasses and all UIViewConttroller subclasses have access to the current style:

myUIView.traitCollection.userInterfaceStyle == .dark
myUIViewController.traitCollection.userInterfaceStyle == .dark

To detect live changes of the style, here is the full detailed answer

Answer 2

For iOS 13, you can use this property to check if current style is dark mode or not:

if #available(iOS 13.0, *) {
    if UITraitCollection.current.userInterfaceStyle == .dark {
        print("Dark mode")
    }
    else {
        print("Light mode")
    }
}

Answer 3

You should check the userInterfaceStyle variable of UITraitCollection, same as on tvOS and macOS.

switch traitCollection.userInterfaceStyle {
case .light: //light mode
case .dark: //dark mode
case .unspecified: //the user interface style is not specified
}

You should use the traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) function of UIView/UIViewController to detect changes in the interface environment (including changes in the user interface style).

From Apple Developer Documentation:

The system calls this method when the iOS interface environment changes. Implement this method in view controllers and views, according to your app’s needs, to respond to such changes. For example, you might adjust the layout of the subviews of a view controller when an iPhone is rotated from portrait to landscape orientation. The default implementation of this method is empty.

System default UI elements (such as UITabBar or UISearchBar) automatically adapt to the new user interface style.

Answer 4

As mentioned by daveextreme, checking the current view user interface style doesn't always return the system style when you use the overrideUserInterfaceStyle property. In such cases it may be better to use the following code:

switch UIScreen.main.traitCollection.userInterfaceStyle {
case .light: //light mode
case .dark: //dark mode
case .unspecified: //the user interface style is not specified
}

Answer 5

in objective-c you'd want to do:

if( self.traitCollection.userInterfaceStyle == UIUserInterfaceStyleDark ){

        //is dark
}else{

    //is light

}

Answer 6

1/ for UIView/UIViewController:

self.traitCollection.userInterfaceStyle == .dark

2/ for static or other:

UITraitCollection.current.userInterfaceStyle == .dark

BUT:

//Never use this! You will get wrong value in app extensions (ex. ToDay widget)
UIScreen.main.traitCollection.userInterfaceStyle == .dark //WRONG!

Answer 7

For Swift:

if #available(iOS 12.0, *) {
  switch UIScreen.main.traitCollection.userInterfaceStyle {
    case .dark: // put your dark mode code here
    case .light: 
    case .unspecified: 
  }
}

For Objective C:

if (@available(iOS 12.0, *)) {
        switch (UIScreen.mainScreen.traitCollection.userInterfaceStyle) {
            case UIUserInterfaceStyleDark:
                // put your dark mode code here
                break;
            case UIUserInterfaceStyleLight:
            case UIUserInterfaceStyleUnspecified:
                break;
            default:
                break;
        }
}

For more information watch this WWDC2019 video

Answer 8

Objective C

To detect when dark mode is enabled or disabled via the Control Centre use an "appDidBecomeActive" notification that will be triggered when you return to your app.

//----------------------------------------------------------------------------
//                          viewWillAppear
//----------------------------------------------------------------------------
- (void)viewWillAppear {
    [super viewWillAppear];

    [[NSNotificationCenter defaultCenter]addObserver:self
                                   selector:@selector(appDidBecomeActive:)
                                   name:UIApplicationDidBecomeActiveNotification
                                   object:nil];

}

Don't forget to remove it when you're finished:

//------------------------------------------------------------------------------------
//                    viewWillDisappear
//------------------------------------------------------------------------------------
- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];

    [[NSNotificationCenter defaultCenter] removeObserver:self        
                                 name:UIApplicationDidBecomeActiveNotification 
                                 object:nil];

}

Do what ever you need to when dark mode changes:

//----------------------------------------------------------------------------
//                          appDidBecomeActive
//----------------------------------------------------------------------------
-(void)appDidBecomeActive:(NSNotification*)note {
    if (@available(iOS 13.0, *)) {
        if( self.traitCollection.userInterfaceStyle == UIUserInterfaceStyleDark ){
            //dark mode
        }
        else {
            //not dark mode
        }
    }
    else {
        //fall back for older versions
    }
}

Answer 9

Create a class function for write method 1 time and use everywhere you want

func isDarkMode() -> Bool{
    if #available(iOS 12.0, *) {
        if UIScreen.main.traitCollection.userInterfaceStyle == .dark {
            return true
        } else {
            return false
        }
    } else {
       return false
    }
}  

Answer 10

Helper method below that works on any iOS version:

var isDarkMode: Bool {
    guard #available(iOS 12.0, *) else {
        return false
    }

    return UIScreen.main.traitCollection.userInterfaceStyle == .dark
}

Usage:

view.backgroundColor = isDarkMode ? .black : .white

Answer 11

The best point to detect changes is traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) function of UIView/UIViewController.

override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
    super.traitCollectionDidChange(previousTraitCollection)

    let userInterfaceStyle = traitCollection.userInterfaceStyle // Either .unspecified, .light, or .dark
    // Update your user interface based on the appearance
}

Detecting appearance changes is trivial by overriding traitCollectionDidChange on view controllers. Then, just access the view controller’s traitCollection.userInterfaceStyle.

However, it is important to remember that traitCollectionDidChange may be called for other trait changes, such as the device rotating. You can check if the current appearance is different using this new method:

override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
    super.traitCollectionDidChange(previousTraitCollection)

    let hasUserInterfaceStyleChanged = previousTraitCollection.hasDifferentColorAppearance(comparedTo: traitCollection) // Bool
    // Update your user interface based on the appearance
}

Answer 12

You can use this extension:

import UIKit

extension UIApplication {
    @available(iOS 13.0, *)
    var userInterfaceStyle: UIUserInterfaceStyle? {
        return self.keyWindow?.traitCollection.userInterfaceStyle
    }
}

@available(iOS 13.0, *)
    func setSystemTheme() {
        switch UIApplication.shared.userInterfaceStyle {
        case .dark?:
            currentTheme = .dark
        case .light?:
            currentTheme = .light
        default:
            break
        }
    }

Answer 13

var isDarkMode: Bool {
    guard #available(iOS 12.0, *) else {
        return false
    }
    let window = (UIApplication.shared.delegate as? AppDelegate)?.window
    return window?.traitCollection.userInterfaceStyle == .dark
}

if you are not using window in AppDelegate, call window from SceneDelegate

It is similar to most answers above, but this works better when we are changing modes using

window?.overrideUserInterfaceStyle = .dark

can be called as

isDarkMode ? .black : .white

Answer 14

Some nice extension maybe ?

public extension UIViewController {
    @available(iOS 12.0, *)
    public var isDarkMode: Bool { traitCollection.userInterfaceStyle == .dark }
}

Answer 15

You can Easily Detect Dark Mode or Light Mode with this Method Swift 5

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if traitCollection.userInterfaceStyle == .light {
    print("Light mode")
} else {
    print("Dark mode")
}}

Answer 16

You can use the following code to check for light, or dark mode in your project:

func viewDidLoad() {
    super.viewDidLoad()

    switch traitCollection.userInterfaceStyle {
        case .light, .unspecified:
            // light mode detected
        case .dark:
            // dark mode detected
    }
}

You can also check for changes in the interface style:

override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
    super.traitCollectionDidChange(previousTraitCollection)

    let userInterfaceStyle = traitCollection.userInterfaceStyle // Either .unspecified, .light, or .dark
    // Update your user interface based on the appearance
}

Just like in macOS since Mojave, you can define images for both light and dark mode in your asset catalog so that those images will be used automatically: