[Solved] ‘traitCollectionDidChange’ was deprecated in iOS 17.0. How do I use the replacement? – Ios

The Problem:

In iOS 17, the ‘traitCollectionDidChange’ method is deprecated. How can developers use the replacement APIs to monitor changes in the user interface style (light/dark mode) and execute custom code accordingly?

The Solutions:

Solution 1: Update your code to use new trait change registration APIs

In iOS 17, the traitCollectionDidChange(_:) method is deprecated. To handle changes to the user interface style, you can use the new registerForTraitChanges(_:handler:) or registerForTraitChanges(_:target:action:) methods.

Here’s how you can use the registerForTraitChanges(_:handler:) method to handle changes to the user interface style:

override func viewDidLoad() {
    super.viewDidLoad()

    registerForTraitChanges([UITraitUserInterfaceStyle.self], handler: { (self: Self, previousTraitCollection: UITraitCollection) in
        if self.traitCollection.userInterfaceStyle == .light {
            // Code to execute in light mode
            print("App switched to light mode")
        } else {
            // Code to execute in dark mode
            print("App switched to dark mode")
        }
    })
}

You can also use the registerForTraitChanges(_:target:action:) method to handle changes to the user interface style. Here’s an example:

override func viewDidLoad() {
    super.viewDidLoad()

    registerForTraitChanges([UITraitUserInterfaceStyle.self], target: self, action: #selector(traitCollectionDidChange(_:)))
}

@objc func traitCollectionDidChange(_ traitCollection: UITraitCollection) {
    if traitCollection.userInterfaceStyle == .light {
        // Code to execute in light mode
        print("App switched to light mode")
    } else {
        // Code to execute in dark mode
        print("App switched to dark mode")
    }
}

Note that you should not use both the old and new code in your app, as this can lead to unexpected behavior. If your app’s deployment target is older than iOS 17, you can continue to use the traitCollectionDidChange(_:) method. However, if your app’s deployment target is iOS 17 or later, you should use the new trait change registration APIs.