我正在使用创建全屏图片库UICollectionView。当用户旋转设备,我执行更新的UICollectionView内
UICollectionView
func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator)
我以UIViewController模态呈现,并UICollectionView占据了全屏。在中viewDidLoad,我将流程布局创建为:
UIViewController
viewDidLoad
let flowLayout = UICollectionViewFlowLayout() flowLayout.scrollDirection = .horizontal flowLayout.minimumInteritemSpacing = 0 flowLayout.minimumLineSpacing = 0 photosCollectionView.isPagingEnabled = true photosCollectionView.setCollectionViewLayout(flowLayout, animated: true)
我也有这样的大小:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { return photosCollectionView.frame.size }
当我旋转设备时,viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator)它永远不会被调用,这将导致UICollectionViewLayout无法更新。旋转设备时,确实收到消息:
viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator)
UICollectionViewLayout
The behavior of the UICollectionViewFlowLayout is not defined because: the item height must be less than the height of the UICollectionView minus the section insets top and bottom values, minus the content insets top and bottom values.
我已在线阅读可以添加的内容:
self.automaticallyAdjustsScrollViewInsets = false
到UIViewController,但已经没有影响。没有任何内容或版块插图UICollectionView。
我也有super.viewWillTransition在函数内的被调用。谁能协助我解决造成此问题的原因?
super.viewWillTransition
如果您只关心设备旋转时的布局,请使用:
override func viewDidLayoutSubviews() { super.viewDidLayoutSubviews() collectionView.collectionViewLayout.invalidateLayout() collectionView.layoutIfNeeded() }
从苹果文档:
public func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator)
当视图控制器的视图大小由其父级更改时(即,其窗口旋转或调整大小时,对于根视图控制器),将调用此方法。如果重写此方法,则应调用super将更改传播给子级,或手动将更改转发给子级。
我猜您可能在该视图的父级上调用了此函数而未调用super
解决方法还包括注册设备旋转:
override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) NotificationCenter.default.addObserver(self, selector: #selector(deviceOrientationDidChange), name: NSNotification.Name.UIDeviceOrientationDidChange, object: nil) } override func viewWillDisappear(_ animated: Bool) { super.viewWillDisappear(animated) NotificationCenter.default.removeObserver(self) } func deviceOrientationDidChange(_ notification: Notification) { let orientation = UIDevice.current.orientation print(orientation) }