iOS 文件預覽（PDF、Excel、World等）之QuickLook框架

QuickLook之工程文件預覽

一、簡介
QuickLook庫可以讓我們的App在iPhone/iPad中直接預覽各個文件了。官方的開發文檔中說明其支持的文件類型有：

1. iWork documents
2. Microsoft Office documents (Office ‘97 and newer)
3. Rich Text Format (RTF) documents
4. PDF files
5. Images
6. Text files whose uniform type identifier (UTI) conforms to the public.text type (see Uniform Type Identifiers Reference)
7. Comma-separated value (csv) files

二、包含哪些類
通過api可以看到有哪些Classes

	import QuickLook.QLBase//基礎類
	import QuickLook.QLPreviewController //預覽Controller
	import QuickLook.QLPreviewItem //單個數據源
	import QuickLook.QLPreviewingController //
	import QuickLook.QLThumbnailProvider
	import QuickLook.QLThumbnailReply
	import QuickLook.QLThumbnailRequest

三、使用demo

方式一：在自己Controller中展示文件如下：

//聲明兩個變量
 	fileprivate var preViewController = QLPreviewController.init()
 	//經過測試：可以是網絡URLStr,必須要下載下來，可以用
    fileprivate var filePath = Bundle.main.path(forResource: "消息提醒", ofType: "xlsx") 
    
    //ViewDidLoad中設置變量
   		 preViewController.delegate = self
         preViewController.dataSource = self
        addChild(preViewController)
        view.addSubview(preViewController.view)
        //佈局，可選
        preViewController.view.snp.makeConstraints { (make) in
            make.left.right.equalToSuperview()
            make.bottom.equalToSuperview()
            make.top.equalTo(topLayoutGuide.snp.bottom)
        }
//遵循代理、DataSource
extension YPreviewVC: QLPreviewControllerDelegate, QLPreviewControllerDataSource {
    func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
        return 1
    }
    
    func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
        return URL.init(fileURLWithPath: filePath!) as QLPreviewItem
    }
    
    
    func previewControllerDidDismiss(_ controller: QLPreviewController) {
        print("用戶界面已消失")
    }
    
    func previewController(_ controller: QLPreviewController, shouldOpen url: URL, for item: QLPreviewItem) -> Bool {
        return false
    }
    
}

方式二：直接調用：

 //直接調用跳轉，用QLPreviewController的默認界面，自帶系統的分享    self.navigationController?.pushViewController(preViewController, animated: true)

QuickLook之網絡URL預覽

一、把文件下載下來：Alamofire 5.0框架
方法如下:

fileprivate var filePath: URL?//聲明的屬性
fileprivate func reqestDownLoad() -> Void {
        let destination = DownloadRequest.suggestedDownloadDestination(for: .documentDirectory)//這是下載存放哪裏
        //自己文件名的在這裏哦
       /* let destination: DownloadRequest.DownloadFileDestination = {[weak self] (url, response) in
            let docmentURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
            let suggestFil = response.suggestedFilename == nil ? "http.xls" : response.suggestedFilename!
//            response.suggestedFilename?//文件名
            let newName = self!.fileName + "." + suggestFil.split(separator: ".").last!.description
            let fileRUL = docmentURL?.appendingPathComponent(newName)
            return (fileRUL!, [.removePreviousFile,.createIntermediateDirectories])
        }*/
        //urlTitle:urlString eg:http://file.xlsx
        Alamofire.download(urlTitle, to: destination).validate().responseData {[weak self] response in
//            case response.d
            debugPrint(response)
            print(response.temporaryURL)
            if response.destinationURL != nil {
                self!.filePath = response.destinationURL//下載完成的完整路徑
                self!.preViewController.reloadData()//刷新即可展示，類似tableView
            }
            print(response.destinationURL)
        }
    }

//MARK: 代理方法
extension YPreFileVC: QLPreviewControllerDelegate, QLPreviewControllerDataSource {
    func numberOfPreviewItems(in controller: QLPreviewController) -> Int {
        if filePath == nil {
            return 0
        }
        return 1 //可以使多個文件
    }
    
    func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> QLPreviewItem {
        return filePath! as QLPreviewItem
    }
    
    func previewControllerDidDismiss(_ controller: QLPreviewController) {
        print("用戶界面已消失")
    }
    
    func previewController(_ controller: QLPreviewController, shouldOpen url: URL, for item: QLPreviewItem) -> Bool {
        return false
    }
}

注意
如果是網絡URL鏈接，下載下來的不想要保存到APP中可以直接在Controller視圖消失的時候直接刪除掉即可

override func viewDidDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        if filePath != nil {//刪錯文件
            do {
                 try             FileManager.default.removeItem(at: filePath!)

            }catch {
                print(error)
                print("刪錯失敗啦")
            }
        }
    }