swift 4 : Change/Clear PDFView content

Question

我想在 Swift 4 中使用 PDFView 框架。( https://developer.apple.com/documentation/pdfkit/pdfview )

以下函数接收 PDF 文档的路径。如果路径有效，则 PDF 文件成功显示。当我调用 openMe(path: String) 两次时出现问题。在这种情况下，旧内容仍然存在，并添加了新内容。我只是想用新内容更改旧内容。

private var pdfData: NSData? = nil

func openMe(path: String) {
   let fileManager = FileManager.default

   if fileManager.fileExists(atPath: path){
       let url = NSURL.fileURL(withPath: path)
       pdfData = NSData(contentsOfFile: path)
       let pdfView = PDFView(frame: self.view.frame)
       pdfViewController?.pdfViewControllerInformsMeasurementDataViewController = self
       pdfView.document = PDFDocument(url: url)
       pdfView.autoScales = true
       pdfView.maxScaleFactor = 0.5
       pdfView.minScaleFactor = pdfView.scaleFactorForSizeToFit
       pdfView.autoresizingMask = [.flexibleWidth, .flexibleHeight]

       self.pdfViewController?.view.addSubview(pdfView)
       self.show(self.pdfViewController!, sender: nil)
    }
}

编辑

引用excitedmicrobe的回答:我只是更改了答案中显示的代码，但导航 Controller 和 PDFView 之间的距离不同。

拳头 openMe 调用:

第二次 openMe 调用:

Answer 1

在这种情况下，您需要将 pdfView 设为全局:

在viewDidLoad()之前添加如下内容:

var pdfView = PDFView()

override func viewDidLoad() {
    super.viewDidLoad()

    // ....
}

然后将您的代码 openMe() 编辑为:

func openMe(path: String) {
     if self.pdfViewController?.view.subviews.contains(pdfView) {
          self.pdfView.removeFromSuperview() // Remove it
      } else {
          // Do Nothing
      }

     let fileManager = FileManager.default

   if fileManager.fileExists(atPath: path){
       let url = NSURL.fileURL(withPath: path)
       pdfData = NSData(contentsOfFile: path)
       self.pdfView = PDFView(frame: self.view.frame)
       pdfViewController?.pdfViewControllerInformsMeasurementDataViewController = self
       pdfView.document = PDFDocument(url: url)
       pdfView.autoScales = true
       pdfView.maxScaleFactor = 0.5
       pdfView.minScaleFactor = pdfView.scaleFactorForSizeToFit
       pdfView.autoresizingMask = [.flexibleWidth, .flexibleHeight]

       self.pdfViewController?.view.addSubview(pdfView)
       self.show(self.pdfViewController!, sender: nil)
     }
}