如何使用 Swift 开发 iOS PDF 查看器或编辑器

 CPDFKit.setLicenseKey("LICENSE_KEY", secret: "LICENSE_SECRET")

 let document = CPDFDocument(url: url)
        
   if let error = document?.error, error._code != CPDFDocumentPasswordError {
      return
   }  
   let pdfView = CPDFView(frame: view.bounds)  
   pdfView.document = document

 view.addSubview(pdfView)

 filePath.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!

   pdfView.frame = self.view.bounds

import UIKit
import ComPDFKit
class ViewController: UIViewController {
    
    public var filePath: String = String()
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        let url = URL(filePath: filePath)
//        let url = URL(fileURLWithPath: fliePath)
        let document = CPDFDocument(url: url)
        
        if let error = document?.error, error._code != CPDFDocumentPasswordError {
            return
        }
        
        let pdfView = CPDFView(frame: view.bounds)
        pdfView.document = document
        view.addSubview(pdfView)
    }
}

import UIKit
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    var window: UIWindow?
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions)
    {
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
        
        let fileURL = Bundle.main.bundleURL.appendingPathComponent("xxxx.pdf")
//        let writbaleURL = copyFileURLToDocumentFolder(fileURL)
        let writbaleURL = fileURL.path()
        
        let tPDFViewController:ViewController = ViewController.init()
        tPDFViewController.fliePath = writbaleURL
        
        window!.rootViewController = UINavigationController(rootViewController: tPDFViewController)
        window!.makeKeyAndVisible()
        guard let _ = (scene as? UIWindowScene) else { return }
    }
    func sceneDidDisconnect(_ scene: UIScene) {
        // Called as the scene is being released by the system.
        // This occurs shortly after the scene enters the background, or when its session is discarded.
        // Release any resources associated with this scene that can be re-created the next time the scene connects.
        // The scene may re-connect later, as its session was not necessarily discarded (see `application:didDiscardSceneSessions` instead).
    }
    func sceneDidBecomeActive(_ scene: UIScene) {
        // Called when the scene has moved from an inactive state to an active state.
        // Use this method to restart any tasks that were paused (or not yet started) when the scene was inactive.
    }
    func sceneWillResignActive(_ scene: UIScene) {
        // Called when the scene will move from an active state to an inactive state.
        // This may occur due to temporary interruptions (ex. an incoming phone call).
    }
    func sceneWillEnterForeground(_ scene: UIScene) {
        // Called as the scene transitions from the background to the foreground.
        // Use this method to undo the changes made on entering the background.
    }
    func sceneDidEnterBackground(_ scene: UIScene) {
        // Called as the scene transitions from the foreground to the background.
        // Use this method to save data, release shared resources, and store enough scene-specific state information
        // to restore the scene back to its current state.
    }
}