在iOS 11中调用self.setNeedsStatusBarAppearanceUpdate（）时，scrollViewDidScroll崩溃

Question

I have this method

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if scrollView is GLIndexedCollectionView { return }

    if scrollView.contentOffset.y >= 120 && self.navBarHidden == true {
        self.navBarHidden = false
        self.setNeedsStatusBarAppearanceUpdate()

        self.topTvConstraint.constant = 44.0
        self.view.layoutIfNeeded()

        self.navigationBarConstraint.constant = 65

        UIView.animate(withDuration: 0.2, delay: 0.0, options: .curveEaseOut, animations: {
            self.view.layoutIfNeeded()
            }, completion: nil)

        var scrollBounds = self.tv.bounds
        scrollBounds.origin = CGPoint(x: 0, y: 185)
        self.tv.bounds = scrollBounds

    }
}

The idea is to animated a top bar and change the status bar color, so I use setNeedsStatusBarAppearanceUpdate to

override var preferredStatusBarStyle: UIStatusBarStyle {
    if navBarHidden {
        return .lightContent
    }

    return .default 
}

but.... if I compile in Xcode 9 and run it in a real device or simulator with iOS 11 it crash in this line

self.setNeedsStatusBarAppearanceUpdate()

and if I try iOS 10.3 works as expected, why?? any help please!

Answer 1

if #available(iOS 11.0, *) {
    setNeedsUpdateOfScreenEdgesDeferringSystemGestures()
} else {
    setNeedsStatusBarAppearanceUpdate()
}

note: This is a small but significant change in iOS 11. If you rely on hiding the status bar to use gestures at the screen edges you should update your app and override setNeedsUpdateOfScreenEdgesDeferringSystemGestures for iOS 11.