ios - 动画期间错误的帧值

Question

我想制作一个类似 iOS 主屏幕文件夹的动画。我在主视图 Controller 中有一个容器 View ，在容器 View 中，我使用动画在两个 View Controller 之间切换。
这是主视图 Controller 类的代码:

class MainContainerViewController: UIViewController {

    @IBOutlet weak var containerView: UIView!

    let duration = 1.0
    var presenting = true
    var originFrame = CGRect.zero
    var indexPathSelectedCell: IndexPath?

    var dismissCompletion: (()->())?


    func cycle(fromViewController: UIViewController, toViewController: UIViewController) {

        let folderViewC = (presenting ? fromViewController : toViewController) as! ViewController
        let projectViewC = (presenting ? toViewController : fromViewController) as! ProjectViewController

        let cellView = (presenting ? (folderViewC.folderCollectionView.cellForItem(at: folderViewC.folderCollectionView.indexPathsForSelectedItems!.first!) as! FolderCollectionViewCell).folderView : projectViewC.containerView)!
        let cellSnapshot = cellView.snapshotView(afterScreenUpdates: false)!
        let cellFrame = containerView.convert(cellView.frame, from: cellView.superview)
        cellSnapshot.frame = cellFrame
        cellView.isHidden = true

        toViewController.view.frame = self.containerView.frame
        toViewController.view.layoutIfNeeded()
        toViewController.view.alpha = 0


        presenting ? (projectViewC.containerView.isHidden = true) : ((folderViewC.folderCollectionView.cellForItem(at: self.indexPathSelectedCell!) as! FolderCollectionViewCell).folderView.isHidden = true)

        fromViewController.willMove(toParentViewController: nil)
        self.addChildViewController(toViewController)
        self.containerView.addSubview(toViewController.view)
        self.containerView.addSubview(cellSnapshot)

        UIView.animate(withDuration: duration, animations: {


            toViewController.view.alpha = 1.0

            let finalFrame = self.presenting ? projectViewC.containerView.frame : self.containerView.convert((folderViewC.folderCollectionView.cellForItem(at: self.indexPathSelectedCell!) as! FolderCollectionViewCell).folderView.frame, from: (folderViewC.folderCollectionView.cellForItem(at: self.indexPathSelectedCell!) as! FolderCollectionViewCell).folderView.superview)

            cellSnapshot.frame = finalFrame
        }) { (_) in

            if !self.presenting {
                self.dismissCompletion?()
            }

            self.presenting ? (projectViewC.containerView.isHidden = false) : ((folderViewC.folderCollectionView.cellForItem(at: self.indexPathSelectedCell!) as! FolderCollectionViewCell).folderView.isHidden = false)

            cellSnapshot.removeFromSuperview()
            fromViewController.view.removeFromSuperview()
            fromViewController.removeFromParentViewController()
            toViewController.didMove(toParentViewController: nil)

        }

    }

}

除了 let finalFrame = self.presenting ? projectViewC.containerView.frame : self.containerView.convert((folderViewC.folderCollectionView.cellForItem(at: self.indexPathSelectedCell!) as!FolderCollectionViewCell).folderView.frame, 来自: (folderViewC.folderCollectionView.cellForItem(at: self.indexPathSelectedCell! ) as!FolderCollectionViewCell).folderView.superview) 将 finalFrame 设置为错误的值:

• 当它呈现时，快照会出现在屏幕中间
• 当它解散时，Snapshot 会靠近他正确的位置。

let finalFrame = self.presenting ? projectViewC.containerView.frame : self.containerView.convert((folderViewC.folderCollectionView.cellForItem(at: self.indexPathSelectedCell!) as!FolderCollectionViewCell).folderView.frame, 来自: (folderViewC.folderCollectionView.cellForItem(at: self.indexPathSelectedCell! ) as! FolderCollectionViewCell).folderView.superview) 行以这种方式工作:

• 检查它是否正在呈现
• 如果它正在呈现，则将常量设置为最终文件夹 View 的frame值
• 如果取消转换所选 Collection View 单元格的 folderView 的 frame 值，则从该 folderView 的父 View 转换

这是整个项目:https://github.com/ale00/OnteamAnon

Answer 1

由于您在 projectViewController 中对 containerView 的大小使用自动布局，因此您需要在这部分代码之后调用 self.containerView 上的 layoutIfNeeded() :

self.addChildViewController(toViewController)
self.containerView.addSubview(toViewController.view)
self.containerView.addSubview(cellSnapshot)

于是变成了:

self.addChildViewController(toViewController)
self.containerView.addSubview(toViewController.view)
self.containerView.addSubview(cellSnapshot)
self.containerView.layoutIfNeeded()