Question

如何使用QLPreviewController打开和查看从Web服务获取的文档文件的URL。

Answer 1

你不能这样做。文档可以很好地解释这一点，但是，您想尝试制作自己的查看器。祝你好运！

请参阅：

您可以在网站上显示：“创建和配置文档交互控制器”

- (UIDocumentInteractionController *) setupControllerWithURL: (NSURL) fileURL
usingDelegate: (id <UIDocumentInteractionControllerDelegate>) interactionDelegate {

UIDocumentInteractionController *interactionController =
    [UIDocumentInteractionController interactionControllerWithURL: fileURL];
interactionController.delegate = interactionDelegate;

return interactionController;}

“一旦有了文档交互控制器，就可以使用其属性来获取有关相关文件的信息，包括其名称，类型和URL。”

Answer 2

显示某种进度微调器。
使用~/documents和URLSession将文件下载到URLSessionDownloadTask文件夹。
隐藏进度微调器。
然后，您需要创建一个实现QLPreviewControllerDataSource的类的实例并保存您的文档。

隐藏进度微调器并显示QLPreviewController

import UIKit
import QuickLook


class Document: NSObject, QLPreviewItem {
    var previewItemURL: URL?
}

class PreviewDataSource: NSObject, QLPreviewControllerDataSource {

    var document: Document?

    func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
        return document != nil ? 1 : 0
    }

    func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
        return document!
    }
}

class ProgressLoadingViewController: UIViewController {

    var session: URLSession = URLSession(configuration: URLSessionConfiguration.default)
    var downloadTask: URLSessionDownloadTask?

    var dataSource: PreviewDataSource?

    override func viewDidLoad() {
        super.viewDidLoad()
        startDownload()
    }

    func startDownload() {
        // start progres spinner
        downloadTask = session.downloadTask(with: URL(string: "http://che.org.il/wp-content/uploads/2016/12/pdf-sample.pdf")!) { [weak self] (downloadLocation, response, error) in
            guard // check if download went correctly
                error != nil,
                let filename = response?.suggestedFilename,
                let downloadLocation = downloadLocation
                else {
                    print("Something went wrong: \(error!)")
                    return
            }

            // copy file
            let fileManager = FileManager.default
            let targetPath = URL(fileURLWithPath: filename, relativeTo: fileManager.temporaryDirectory)
            do {
                try fileManager.copyItem(at: downloadLocation, to: targetPath)
            } catch let fileError {
                print("Copying failed: \(fileError)")
                return
            }

            // prepare preview
            let document = Document()
            document.previewItemURL = targetPath
            self?.dataSource? = PreviewDataSource()
            self?.dataSource?.document = document

            let qlViewController = QLPreviewController()
            qlViewController.dataSource = self?.dataSource

            // hide progress spinner
            self?.present(qlViewController, animated: true) {
                self?.downloadTask = nil
                qlViewController.reloadData()
            }
        }
        downloadTask?.resume()
    }
}

当然，这个长期完成函数应该分成几个，然后移到它自己的类DocumentDownloadManager。

打开并查看文档文件URL

2 个答案: