UIImage（contentsOfFile :)返回nil，尽pipe文件存在于caching目录中
我试图保存一个覆盖在caching目录中的地图的快照，并在存在时检索它。 但是，尽pipe文件正在创build，UIImage（contentsOfFile :)返回nil，当我尝试检索它。 我已经打印了写入和读取的文件path，它们是相同的，并通过下载容器并检查目录和文件确定存在validation了文件存在。
任何想法这里的问题是什么？
let cachesDirectory: URL = { let urls = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask) return urls[urls.endIndex - 1] }() let mapCachesDirectory = cachesDirectory.appendingPathComponent("map-snapshots", isDirectory: true) func configureMap(data: NSSet?) { mapView.isZoomEnabled = false mapView.isScrollEnabled = false mapView.isUserInteractionEnabled = false guard let data = data as? Set<SessionData>, data.count > 0 else { return } activityIndicatorView.isHidden = false activityIndicatorView.startAnimating() DispatchQueue.global(qos: .userInitiated).async { var points = [CLLocationCoordinate2D]() for object in data { guard object.locationLatitude != 0, object.locationLatitude != 0 else { continue } points.append(CLLocationCoordinate2DMake(object.locationLatitude, object.locationLongitude)) } DispatchQueue.main.async(execute: { self.createOverlay(points: points) self.activityIndicatorView.stopAnimating() self.activityIndicatorView.isHidden = true self.cacheMapImage(view: self.mapView) }) } } func cacheMapImage(view: UIView) { UIGraphicsBeginImageContextWithOptions(view.bounds.size, true, 0) view.drawHierarchy(in: view.bounds, afterScreenUpdates: true) let compositeImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() DispatchQueue.global(qos: .userInitiated).async { if let compositeImage = compositeImage, let info = self.info { let data = UIImagePNGRepresentation(compositeImage) do { var isDirectory: ObjCBool = false let fileManager = FileManager.default if fileManager.fileExists(atPath: self.mapCachesDirectory.absoluteString, isDirectory: &isDirectory) == false { try fileManager.createDirectory(at: self.mapCachesDirectory, withIntermediateDirectories: true, attributes: nil) } let fileURL = self.mapCachesDirectory.appendingPathComponent(info.uid).appendingPathExtension("png") try data?.write(to: fileURL) print("\(fileURL.absoluteString) Saved") } catch { log.error(error) } } } } func cachedMapImage() -> UIImage? { guard let info = info else { return nil } let filePath = mapCachesDirectory.appendingPathComponent(info.uid).appendingPathExtension("png").absoluteString let image = UIImage(contentsOfFile: filePath) print("\(filePath): \(image)") return image } func createOverlay(points: [CLLocationCoordinate2D]) { guard points.count > 0 else { return } let overlay = MKGeodesicPolyline(coordinates: points, count: points.count) mapView.add(overlay) let inset: CGFloat = 50.0 mapView.setVisibleMapRect(overlay.boundingMapRect, edgePadding: UIEdgeInsetsMake(inset,inset,inset,inset), animated: true) } 问题在于你正在使用URL属性absoluteString，你应该使用path属性。 absoluteString and path属性之间的区别在于，absoluteString包含了文件url scheme（“file：//”），这就是它没有find文件的原因，而是它的绝对path。