如何直接从 URL 快速打开 pdf 文件

Posted 2023-03-16

【中文标题】如何直接从 URL 快速打开 pdf 文件

【英文标题】：How to open pdf file in swift directly from URL

【发布时间】：2019-12-12 07:47:43

【问题描述】：

我是 swift 新手，无法从 url 打开 pdf 文件

我的代码是这样的

 @IBOutlet var webview: WKWebView!


    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view.

        webview.navigationDelegate = self

        let url = URL(string: "http://www.orimi.com/pdf-test.pdf")
        self.webview.load(URLRequest(url: url!))

    

    func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) 
        print("Start loading")
    

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) 
        print("End loading")
    

我正在使用此代码，我可以打开 url 链接和图像，但无法打开 pdf 文件

【问题讨论】：

运行上面的代码会发生什么

@user1374 它什么也没显示。

如果 WKWebView WKNavigationDelegate 是否设置了委托

【参考方案1】：

如果您使用 >= ios 11，则可以使用 Apples PDFKit。这里是例子。

import PDFKit


class ViewController: UIViewController 
    override func viewDidLoad() 
        super.viewDidLoad()

        let pdfView = PDFView(frame: view.bounds)
        view.addSubview(pdfView)

        if let url = URL(string: link_of_pdf), let document = PDFDocument(url: url) 
            pdfView.document = document
        
    

但是如果你需要低于 iOS 11 的支持，你可以使用CGPDFDocument（但你需要做很多工作），或者找到第三方库。

【讨论】：

如果 URL 已将 pdf 更改为 Web URL 会怎样

你也可以使用网址

【参考方案2】：

您正在尝试将 http-Url 加载到 iOS 默认禁止的 WebView 中。您可以使用 https-Url 尝试相同的代码或更改 Info.plist 中的传输安全设置以允许任意加载

另一个有用的想法可能是使用 SFSafariViewController 从另一个 url 显示网站或文档。

【参考方案3】：

试试下面的代码告诉我

 @IBOutlet weak var webView: WKWebView!


override func viewWillAppear(_ animated: Bool) 

        super.viewWillAppear(true)
        self.initialSetup()
    

    private func initialSetup () 
        webView.navigationDelegate = self
        self.loadhtmlStringImage()

    

    private func loadHTMLStringImage() -> Void 
            let htmlString = "<p>Identify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the imagesIdentify the arrow-marked structures in the images</p>"
            webView.loadHTMLString(htmlString, baseURL: nil)
        

【参考方案4】：

你为什么使用WKWebView，因为你可以使用最常用的方法，那就是使用UIDocumentInteractionController和UIAlertController

检查这部分使用流行的Alamofire 和progressview 的代码（你可以使用任何你喜欢的类似功能的库，当然也可以使用URLSession）。

注意如果你在你的控制器中使用它，它必须实现委托UIDocumentInteractionControllerDelegate。

这里是带有下载功能和进度条的完整源代码：

class MyController: UIViewController, UIDocumentInteractionControllerDelegate 

        var progressView: UIProgressView?    

        override func viewDidLoad() 
            super.viewDidLoad()
                       

        func downloadCommentFile(id: Int) 
            let destination = DownloadRequest.suggestedDownloadDestination(for: .documentDirectory)  

            //MARK: Progress controller
            let alertView = UIAlertController(title: "Downloading", message: "Downloading file", preferredStyle: .alert)
            alertView.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))

            //  Show UIAlertController it to your users
            present(alertView, animated: true, completion: 
                //  Add your progressbar after alert is shown (and measured)
                let margin:CGFloat = 8.0
                let rect = CGRect(x: margin, y: 72.0, width: alertView.view.frame.width - margin * 2.0 , height: 10.0)
                self.progressView = UIProgressView(frame: rect)
                self.progressView!.progress = 0
                self.progressView!.tintColor = self.view.tintColor
                alertView.view.addSubview(self.progressView!)
            )

            let url = "http://MyUrl/DownloadFile"
            let headers = ["Header1": "header 1 value"]

            Alamofire.download(url,
                method: .post,
                parameters: ["id": id],
                encoding: JSONEncoding.default,
                headers: headers,
                to: destination).downloadProgress(closure:  (progress) in
                    //progress closure                  
                    self.progressView?.setProgress(Float(progress.fractionCompleted), animated: true)
                ).response(completionHandler:  (DefaultDownloadResponse) in
                    //here you able to access the DefaultDownloadResponse
                    //result closure
                    alertView.dismiss(animated: true, completion: 
                        let viewer = UIDocumentInteractionController(url: DefaultDownloadResponse.destinationURL!)
                        viewer.delegate = self
                        viewer.presentPreview(animated: true)
                )
            )      
        

        func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController 
            return self
        

        private func documentInteractionControllerViewForPreview(controller: UIDocumentInteractionController!) -> UIView! 
            return self.view
        

        func documentInteractionControllerRectForPreview(_ controller: UIDocumentInteractionController) -> CGRect 
            return self.view.frame
        
    

【参考方案5】：

如果你想在 WKWebView 中加载你的 pdf 文件，你可以使用下面的代码：-

import UIKit
import WebKit

class WebViewController: UIViewController 

    @IBOutlet weak var webView: WKWebView! 
        didSet 
            webView.navigationDelegate = self
        
    

    override func viewDidLoad() 
        super.viewDidLoad()
        loadWebView()
    

    override func viewWillDisappear(_ animated: Bool) 
        super.viewWillDisappear(true)
        hideLoader()
    

    private func loadWebView() 
        showLoader()
        let request = URLRequest(url: URL(string: "http://www.orimi.com/pdf-test.pdf)!)
        DispatchQueue.main.async 
            self.webView.load(request)
        
    

    private func showLoader() 
        DispatchQueue.main.async 
            //show your loader
        
    

    private func hideLoader() 
        DispatchQueue.main.async 
            //hide your loader
        
    



extension WebViewController: WKNavigationDelegate 

    func webView(_ webView: WKWebView, didFailProvisionalNavigation navigation: WKNavigation!, withError error: Error) 
        hideLoader()
        showAlert(error.localizedDescription)
    

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) 
        hideLoader()