QuickLook类不工作

我有这个类，工作正常

导入UIKit导入QuickLook

class ViewController: UITableViewController, QLPreviewControllerDataSource { var urlList : [NSURL]? = { if let fileURL1 = NSBundle.mainBundle().URLForResource("Essay", withExtension:"txt"), let fileURL2 = NSBundle.mainBundle().URLForResource("Image", withExtension:"jpg"), let fileURL3 = NSBundle.mainBundle().URLForResource("Letter", withExtension:"docx"), let fileURL4 = NSBundle.mainBundle().URLForResource("Newsletter", withExtension:"pages"), let fileURL5 = NSBundle.mainBundle().URLForResource("Presentation", withExtension:"key"), let fileURL6 = NSBundle.mainBundle().URLForResource("VisualReport", withExtension:"pdf"), let fileURL7 = NSBundle.mainBundle().URLForResource("aaa", withExtension:"x") { return [ fileURL1 , fileURL2, fileURL3, fileURL4, fileURL5, fileURL6, fileURL7 ] } return nil }() override func viewDidLoad() { super.viewDidLoad() } override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int { if let list = urlList { return list.count } return 0 } override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCellWithIdentifier("default", forIndexPath: indexPath) if let list = urlList, let fileName = list[indexPath.row].lastPathComponent { cell.textLabel?.text = fileName } return cell } override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) { let previewQL = QLPreviewController() previewQL.dataSource = self as QLPreviewControllerDataSource previewQL.currentPreviewItemIndex = indexPath.row showViewController(previewQL, sender: nil) } func numberOfPreviewItemsInPreviewController(controller: QLPreviewController) -> Int { if let list = urlList { return list.count } return 0 } func previewController(controller: QLPreviewController, previewItemAtIndex index: Int) -> QLPreviewItem { var fileURL : NSURL? if let list = urlList, let filePath = list[index].lastPathComponent { fileURL = NSBundle.mainBundle().URLForResource(filePath, withExtension:nil) } print(fileURL!) return fileURL! } } 

但是当我改变快速查看是另一个类如下，它停止工作？

 import UIKit import QuickLook class ViewController: UITableViewController { var urlList : [NSURL]? = { if let fileURL1 = NSBundle.mainBundle().URLForResource("Essay", withExtension:"txt"), let fileURL2 = NSBundle.mainBundle().URLForResource("Image", withExtension:"jpg"), let fileURL3 = NSBundle.mainBundle().URLForResource("Letter", withExtension:"docx"), let fileURL4 = NSBundle.mainBundle().URLForResource("Newsletter", withExtension:"pages"), let fileURL5 = NSBundle.mainBundle().URLForResource("Presentation", withExtension:"key"), let fileURL6 = NSBundle.mainBundle().URLForResource("VisualReport", withExtension:"pdf"), let fileURL7 = NSBundle.mainBundle().URLForResource("aaa", withExtension:"x") { return [ fileURL1 , fileURL2, fileURL3, fileURL4, fileURL5, fileURL6, fileURL7 ] } return nil }() override func viewDidLoad() { super.viewDidLoad() } override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int { if let list = urlList { return list.count // 2 } return 0 } override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCellWithIdentifier("default", forIndexPath: indexPath) if let list = urlList, let fileName = list[indexPath.row].lastPathComponent { cell.textLabel?.text = fileName // 3 } return cell } override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) { _ = PreviewController(controller: self, documentURL: urlList![indexPath.row]) } } 

和

 import UIKit import QuickLook class PreviewController: NSObject, QLPreviewControllerDataSource { var documentURL: NSURL init(controller: ViewController, documentURL: NSURL) { self.documentURL = documentURL super.init() let previewQL = QLPreviewController() previewQL.dataSource = self as QLPreviewControllerDataSource previewQL.currentPreviewItemIndex = 0 controller.showViewController(previewQL, sender: nil) } func numberOfPreviewItemsInPreviewController(controller: QLPreviewController) -> Int { return 1 } func previewController(controller: QLPreviewController, previewItemAtIndex index: Int) -> QLPreviewItem { return documentURL } } 

任何想法为什么重构类PreviewController不起作用？

Answer 1

我发现这个作品

 import UIKit import QuickLook class PreviewController: QLPreviewController, QLPreviewControllerDataSource { var documentURL: NSURL! override func viewDidLoad() { super.viewDidLoad() self.dataSource = self } func show(controller: UIViewController, documentURL: NSURL) { self.documentURL = documentURL if let navController = controller.navigationController { navController.pushViewController(self, animated: true) } else { controller.showViewController(self, sender: nil) } } func numberOfPreviewItemsInPreviewController(controller: QLPreviewController) -> Int { return 1 } func previewController(controller: QLPreviewController, previewItemAtIndex index: Int) -> QLPreviewItem { return documentURL } } 

像这样打电话

 func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) { let previewController = PreviewController() previewController.show(self, documentURL: urlList[indexPath.row]) }