0

请有人帮忙。一旦用户单击 pdf 查看器上的共享按钮，我想添加一条警报消息，我正在使用 UIDocumentInteractionController 预览 pdf 文档。我想知道是否有任何可以覆盖的委托方法或函数，在打开共享表之前我可以在哪里添加警报？[！[在此处输入图像描述][1]][1]

class ViewController: UIViewController {
    
    var documentController : UIDocumentInteractionController!

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

    @IBAction private func buttonTapped(_ sender: Any) {
        
       guard let fileURL = Bundle.main.url(forResource: "infomation", withExtension: "pdf") else {return}
        documentController = UIDocumentInteractionController.init(url: fileURL)
        documentController.delegate = self
        documentController.presentPreview(animated: true)
    }
}

extension ViewController: UIDocumentInteractionControllerDelegate {
    func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController {
        
        return self
    }
    
    func documentInteractionControllerWillPresentOpenInMenu(_ controller: UIDocumentInteractionController) {
  
    }
    
    func documentInteractionControllerWillPresentOptionsMenu(_ controller: UIDocumentInteractionController) {
    
    }
    
    func documentInteractionController(_ controller: UIDocumentInteractionController, willBeginSendingToApplication application: String?) {
    
    }
}

但是当我单击共享按钮时，它们都没有被调用，即使我已将委托设置为我的视图控制器。有没有办法可以做到这一点？

4

1 回答 1

1

解释：

如果不通过迭代所有子视图并覆盖按钮的动作和目标来将其组合在一起，就没有办法做到这一点。

一种干净的方法是创建自己的预览控制器，如下所示。如果您添加QLPreviewControllerto UINavigationController，它会自动创建一个bottom toolbar您不想要的。要解决此问题，请将其添加为常规的子控制器UIViewController并创建自定义导航栏。

您还可以使用UTI来UIActivityItem确定如何共享项目。我只实现了预览和基本的共享功能，但其余的应该非常容易做到，而且至少它比UIDocumentInteractionController你完全控制一切更可定制。

现在对于执行所有这些的代码：

//
//  ViewController.swift
//  CustomDocumentController
//
//  Created by brandon on 2022-01-13.
//

import UIKit
import QuickLook
import MobileCoreServices
import UniformTypeIdentifiers

private class PreviewItem: NSObject, QLPreviewItem {
    var previewItemURL: URL?
    var previewItemTitle: String?
    
    init(title: String, url: URL) {
        super.init()
        
        previewItemURL = url
        previewItemTitle = title
    }
}

class DocumentInteractionController: UIViewController {
    
    private let url: URL
    
    private lazy var navigationBar: UINavigationBar = {
        let navigationBar = UINavigationBar()
        let navigationItem = UINavigationItem(title: name ?? "Document")
        navigationItem.hidesBackButton = true
        navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(onDone))
        navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(onShare)) //UIImage(systemName: "square.and.arrow.up")
        navigationBar.pushItem(navigationItem, animated: false)
        return navigationBar
    }()
    
    private lazy var previewController: QLPreviewController = {
        let previewController = QLPreviewController()
        previewController.title = name
        previewController.dataSource = self
        previewController.delegate = self
        previewController.reloadData()
        return previewController
    }()
    
    var uti: String? {
        didSet {
            previewController.reloadData()
        }
    }
    
    var name: String? {
        didSet {
            previewController.title = name
            navigationBar.topItem?.title = name
        }
    }
    
    init(url: URL) {
        self.url = url
        super.init(nibName: nil, bundle: nil)
        //super.init(rootViewController: self.previewController)
        self.modalPresentationStyle = .fullScreen
        
        name = (try? url.resourceValues(forKeys: [.localizedNameKey]))?.localizedName
        uti = (try? url.resourceValues(forKeys: [.typeIdentifierKey]))?.typeIdentifier
        
        if uti == nil {
            if #available(iOS 15.0, *) {
                uti = UTType.url.identifier
            } else {
                uti = String(kUTTypeURL)
            }
        }
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()

        addChild(previewController)
        previewController.didMove(toParent: self)
        
        let separator = UIView()
        separator.backgroundColor = .lightGray
        
        view.addSubview(navigationBar)
        view.addSubview(separator)
        view.addSubview(previewController.view)
        
        NSLayoutConstraint.activate([
            navigationBar.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
            navigationBar.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor),
            navigationBar.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
            
            separator.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
            separator.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor),
            separator.topAnchor.constraint(equalTo: navigationBar.bottomAnchor),
            separator.heightAnchor.constraint(equalToConstant: 1.0 / UIScreen.main.scale),
            
            previewController.view.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
            previewController.view.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor),
            previewController.view.topAnchor.constraint(equalTo: separator.bottomAnchor),
            previewController.view.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])
        
        [navigationBar, separator, previewController.view].forEach({
            $0?.translatesAutoresizingMaskIntoConstraints = false
        })
        
        navigationBar.barTintColor = previewController.view.backgroundColor
        view.backgroundColor = previewController.view.backgroundColor
    }
}

extension DocumentInteractionController: QLPreviewControllerDelegate, QLPreviewControllerDataSource {
    func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
        return 1
    }
    
    func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
        return PreviewItem(title: name ?? "Document", url: url)
    }
}

extension DocumentInteractionController {
    @objc
    private func onDone() {
        self.dismiss(animated: true, completion: nil)
    }
    
    @objc
    private func onShare() {
        let activityViewController = UIActivityViewController(activityItems: [url],
                                                              applicationActivities: nil)
        
        activityViewController.excludedActivityTypes = [.assignToContact]
        if UIDevice.current.userInterfaceIdiom == .pad {
            activityViewController.popoverPresentationController?.sourceView = self.view
        }
        self.present(activityViewController, animated: true, completion: nil)
    }
}

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let url = Bundle.main.url(forResource: "Testing", withExtension: ".md")
        let doc = DocumentInteractionController(url: url!)
        
        DispatchQueue.main.asyncAfter(deadline: .now() + 2.0) {
            self.present(doc, animated: true, completion: nil)
        }
    }
}

截图：

图像-1 图像-2

于 2022-01-13T18:11:58.633 回答