从特定视图创建 PDF 文件

Posted 2023-02-24

【中文标题】从特定视图创建 PDF 文件

【英文标题】：Create a PDF file from a specific View

【发布时间】：2021-02-03 10:42:17

【问题描述】：

我想从视图 X 创建一个 PDF 文件。从 Alex 的问题中报告和提取的代码有效，但只创建了主视图的 PDF（视图 A）。我如何告诉他创建 View X 的 PDF？

Convert SwiftUI View to PDF on ios

// From Main View A
func savePdf() 
        let view = ViewX() // <--- This is the View I would like to transform, not linked to View A
        let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        let outputFileURL = documentDirectory.appendingPathComponent("ViewX.pdf")

        let dpiScale: CGFloat = 4

        // for A5 page size inches * 72
        let pageSize = CGSize(width: 5.8 * 72, height: 8.3 * 72)
        
        let pdfVC = UIHostingController(rootView: view) 
        pdfVC.view.frame = CGRect(origin: .zero, size: pageSize * dpiScale)

        let rootVC = UIApplication.shared.windows.first?.rootViewController
        rootVC?.addChild(pdfVC)
        rootVC?.view.insertSubview(pdfVC.view, at: 0)

        let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(origin: .zero, size: pageSize))

        DispatchQueue.main.async 
            do 
                try pdfRenderer.writePDF(to: outputFileURL, withActions:  (context) in
                    context.beginPage()
                    rootVC?.view.layer.render(in: context.cgContext)
                    self.pdfURL = outputFileURL
                )
             catch 
                print("error.localizedDescription")
            
        
        pdfVC.removeFromParent()
        pdfVC.view.removeFromSuperview()
    

【参考方案1】：

我遇到了同样的问题。这对我有用：

import SwiftUI

func exportToPDF() 
    let outputFileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("SwiftUI.pdf")
    let pageSize = CGSize(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
    
    //View to render on PDF
    let myUIHostingController = UIHostingController(rootView: ContentView())
    myUIHostingController.view.frame = CGRect(origin: .zero, size: pageSize)
    
    
    //Render the view behind all other views
    guard let rootVC = UIApplication.shared.windows.first?.rootViewController else 
        print("ERROR: Could not find root ViewController.")
        return
    
    rootVC.addChild(myUIHostingController)
    //at: 0 -> draws behind all other views
    //at: UIApplication.shared.windows.count -> draw in front
    rootVC.view.insertSubview(myUIHostingController.view, at: 0)
    
    
    //Render the PDF
    let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(origin: .zero, size: pageSize))
    DispatchQueue.main.async 
        do 
            try pdfRenderer.writePDF(to: outputFileURL, withActions:  (context) in
                context.beginPage()
                myUIHostingController.view.layer.render(in: context.cgContext)
            )
            print("wrote file to: \(outputFileURL.path)")
         catch 
            print("Could not create PDF file: \(error.localizedDescription)")
        
        
        //Remove rendered view
        myUIHostingController.removeFromParent()
        myUIHostingController.view.removeFromSuperview()
    

注意：当您尝试导出同一个视图时，请勿尝试在带有 .onAppear 的视图中使用此功能。这自然会导致无限循环。

我希望这会有所帮助！

【参考方案2】：

来自链接问题的答案：

您在所有其他视图后面的窗口上呈现 HostingController，并在 PDF 上绘制其层。

这将是第一个视图，我猜是索引 0。从您提供的功能来看，这一行看起来很相关：

rootVC?.view.insertSubview(pdfVC.view, at: 0)

将0 替换为您想要的视图。