小编Pav*_*nov的帖子

我正在检查.lazy高阶函数,并且得到了一些与flatMap函数相关的有趣编译错误(可能还有其他函数)

例子

 
let array = [1, 2, 3, 4, 5, 6]

array
    .flatMap {
        print("DD")
        return $0 // Cannot convert return expression of type 'Int' to return type 'String?'
    }
    .forEach {
        print("SS")
        print($0)
}

评论一下

 
array
    .flatMap {
//        print("DD")
        return $0
    }
    .forEach {
        print("SS")
        print($0)
}

一切正常......更有趣的例子

 
array
    .flatMap {
        let z = $0
        return $0  // Or return z - all is the same "Cannot convert return expression of type 'Int' to return type …

我用UICollectionViewCompositionalLayout。所有部分都有圆形背景。背景刚刚添加到所有部分

    let background = NSCollectionLayoutDecorationItem.background(elementKind: "background")
    section.decorationItems = [background]

后来注册了

    layout.register(RoundedView.self, forDecorationViewOfKind: "background")

问题是：如何更改背景视图的颜色？是否有使视图出队的功能？我已经尝试过了

override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
    preconditionFailure("")
}

但它没有被调用

所有相关代码：相当愚蠢的背景视图

final class RoundedView: UICollectionReusableView {
    override init(frame: CGRect) {
        super.init(frame: frame)
        config()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        config()
    }

    private func config() {
        self.layer.cornerRadius = Constant.Dimens.cornerRadius
        self.clipsToBounds = true
    }
}

进行布局

@available(iOS 13, *)
private static func makeLayout() -> UICollectionViewLayout {
    let itemSize …

我需要将视频文件保存到临时目录并保存对其 URL 的引用。目前我尝试使用 fileManager 创建临时目录，然后 createFile(atPath: tempDirString,contents:vidData,attributes:nil)。但我无法保存对该文件的完整引用。

我尝试过的：

PHCachingImageManager().requestAVAsset(forVideo: (cell?.assetPH)!, options: nil) { (avAsset, _, _) in
    if let avAsset = avAsset {
        print(avAsset, " the avasset?")
        // vidAVAsset = avAsset

        let avPlayerItem = AVPlayerItem(asset: avAsset)
        let avPlayer = AVPlayer(playerItem: avPlayerItem)
        print(avPlayer, "<-- good?")

        let finalURL = self.urlOfCurrentlyPlayingInPlayer(player: avPlayer)
        print(finalURL, "<-- finalURL YEAH EYAHY YEAH?!?!?")
        // newUserTakenVideo.videoURL = finalURL

        let url = self.addVidToTempURL(vidURL: finalURL!)
        newUserTakenVideo.videoURL = url
        // let newUserTakenVideo = SelectedMedia(videoURL: finalURL, phAsset: (cell?.assetPH)!, thumbnailImg: (cell?.imageView.image)!, uniqueCellID: indexPath)
        // …