如何在iOS11 swift 4中预览来自url的ppt文档

我正在尝试预览来自远程url的pdf和ppt文档，我正在使用QuickLookPreviewController来预览文档。 到目前为止，我能够预览pdf和video但是当我打开ppt它打开quickLookController而不是ppt预览我只看到这个

我不知道这是否是QLPreviewController的问题，或者我需要做一些额外的事情才能打开它。 我在下面发布我的代码，以便你能理解什么是错的。

import UIKit import Alamofire import QuickLook class AchievementsDetailViewController: UIViewController,UICollectionViewDelegate,UICollectionViewDataSource,UICollectionViewDelegateFlowLayout,QLPreviewControllerDataSource { let appDelegate = UIApplication.shared.delegate as! AppDelegate var fileURLs = [URL]() let quickLookController = QLPreviewController() override func viewDidLoad() { super.viewDidLoad() self.title = "Achievements View" quickLookController.dataSource = self } override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) getAllAchievementsDetails() } func extractAndBreakFilenameInComponents(fileURL: NSURL) -> (fileName: String, fileExtension: String) { let fileURLParts = fileURL.path!.components(separatedBy: "/") let fileName = fileURLParts.last let filenameParts = fileName?.components(separatedBy: ".") return (filenameParts![0], filenameParts![1]) } func getAllAchievementsDetails() { fileURLs = [] let detailAchievementsURL = "\(WebAPI.baseURL + WebAPI.detailAchievementAPI)\(appDelegate.userId)\(WebAPI.achievementId + id)" Alamofire.request(detailAchievementsURL, method: .get, parameters: nil, encoding: JSONEncoding.default, headers: nil).responseJSON {response in switch response.result { case .success: let resposneString = response.result.value as! String guard let detailAchievementData = Universal.convertStringToDictionary(text: resposneString) else {return} switch response.response?.statusCode { case 200?: let imagesList = detailAchievementData["lstimages"] as! [[String : Any]] for imageData in imagesList { guard let imagePath = imageData["imagesurl"] else {return} let imageString = "\(WebAPI.mediaBaseURL)\(imagePath)" let image = imageString.replacingOccurrences(of: "~", with:"") guard let imageURL = URL(string: image) else {return} self.fileURLs.append(imageURL) } let videosList = detailAchievementData["lstvideos"] as! [[String : Any]] for videoData in videosList { guard let videoPath = videoData["videossurl"] else {return} let videoString = "\(WebAPI.mediaBaseURL)\(videoPath)" let video = videoString.replacingOccurrences(of: "~", with: "") guard let videoURL = URL(string: video) else {return} self.fileURLs.append(videoURL) } let docsList = detailAchievementData["lstdocuments"] as! [[String : Any]] for documentData in docsList { guard let documentPath = documentData["DocumentPath"] else {return} let documentString = "\(WebAPI.mediaBaseURL)\(documentPath)" let document = documentString.replacingOccurrences(of: "~", with: "") guard let escapedAddress = document.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed) else {return} guard let documentURL = URL(string: escapedAddress) else {return} self.fileURLs.append(documentURL) } case 500?: print(resposneString) default: print(resposneString) } case .failure(let error): print(error.localizedDescription) } self.achievementsCollectionView.reloadData() } func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { return fileURLs.count } func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "mediaCell", for: indexPath) as! AchievementDetailCell return cell } func numberOfPreviewItems(in controller: QLPreviewController) -> Int { return fileURLs.count } func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem { return fileURLs[index] as QLPreviewItem } func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) { let currentFileParts = extractAndBreakFilenameInComponents(fileURL: fileURLs[indexPath.row] as NSURL) if currentFileParts.fileExtension == "pdf" || currentFileParts.fileExtension == "ppt" { if QLPreviewController.canPreview(fileURLs[indexPath.row] as QLPreviewItem) { quickLookController.currentPreviewItemIndex = indexPath.row navigationController?.pushViewController(quickLookController, animated: true) } } } 

我希望我的代码一切都很好……如果没有，请指导我..提前谢谢