traitCollectionDidChange strange behavior
问题 override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) { super.traitCollectionDidChange(previousTraitCollection) if traitCollection.hasDifferentColorAppearance(comparedTo: previousTraitCollection) { print("changed") } } The iOS 13 application just goes to background without changing the mode (light/dark) but the "print" function is called. Is it possible to determine the moment when the mode really changed? Thank You. 回答1: I observed this myself as well. The