如何在swift中使用QLPreviewController显示远程文档

我正在使用QLPreviewController来预览文档。 但我不知道如何显示存储在服务器上的文档。

Answer 1

你不能。 QuickLook仅适用于本地资源文件。 您需要先异步下载数据，将其保存到文档目录或临时文件夹，并在完成后从主线程中显示QLPreviewController：

import UIKit import QuickLook class ViewController: UIViewController, QLPreviewControllerDataSource { let preview = QLPreviewController() let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent("quicklook.pdf") func numberOfPreviewItems(in controller: QLPreviewController) -> Int { return 1 } func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem { return tempURL as QLPreviewItem } override func viewDidLoad() { super.viewDidLoad() preview.dataSource = self preview.currentPreviewItemIndex = 0 let url = URL(string:"https://images.apple.com/environment/pdf/Apple_Environmental_Responsibility_Report_2017.pdf")! URLSession.shared.dataTask(with: url) { data, response, error in guard let data = data, error == nil else { // in case of failure to download your data you need to present alert to the user and update the UI from the main thread DispatchQueue.main.async { UIApplication.shared.isNetworkActivityIndicatorVisible = false let alert = UIAlertController(title: "Alert", message: error?.localizedDescription ?? "Failed to download the pdf!!!", preferredStyle: .alert) alert.addAction(UIAlertAction(title: "OK", style: .default)) self.present(alert, animated: true) } return } // write the downloaded data to a temporary folder or to the document directory if you want to keep the pdf for later usage do { try data.write(to: self.tempURL, options: .atomic) // atomic option overwrites it if needed // you neeed to check if the downloaded data is a valid pdf // and present your controller from the main thread DispatchQueue.main.async { UIApplication.shared.isNetworkActivityIndicatorVisible = false if self.tempURL.typeIdentifier == "com.adobe.pdf" { self.present(self.preview, animated: true) } else { print("the data downloaded it is not a valid pdf file") } } } catch { print(error) return } }.resume() UIApplication.shared.isNetworkActivityIndicatorVisible = true } } extension URL { var typeIdentifier: String? { return (try? resourceValues(forKeys: [.typeIdentifierKey]))?.typeIdentifier } }