如何在iOS中将UIView转换为PDF？

Question

关于如何在App中显示PDF有很多资源UIView.我现在正在做的是从中创建一个PDF UIViews.

例如,我有一个UIView,与像Textviews子视图,UILabels,UIImages,所以我怎么能转换成一个大的 UIView整体,包括其所有子视图和subsubviews到PDF？

我查看过Apple的iOS参考资料.但是,它只涉及将文本/图像片段写入PDF文件.

我面临的问题是我想以PDF格式写入文件的内容很多.如果我将它们逐个写入PDF,那将是一项巨大的工作.这就是我寻找写入UIViewsPDF甚至位图的方法的原因.

我已经尝试过在Stack Overflow中从其他Q/A复制的源代码.但它只给我一个带有UIView边界大小的空白PDF .

-(void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
    // Creates a mutable data object for updating with binary data, like a byte array
    NSMutableData *pdfData = [NSMutableData data];

    // Points the pdf converter to the mutable data object and to the UIView to be converted
    UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
    UIGraphicsBeginPDFPage();

    // draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData
    [aView drawRect:aView.bounds];

    // remove PDF rendering context
    UIGraphicsEndPDFContext();

    // Retrieves the document directories from the iOS device
    NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);

    NSString* documentDirectory = [documentDirectories objectAtIndex:0];
    NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];

    // instructs the mutable data object to write its context to a file on disk
    [pdfData writeToFile:documentDirectoryFilename atomically:YES];
    NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);
}

请帮忙.谢谢.

Answer 1

请注意,以下方法仅创建视图的位图; 它不会创建实际的排版.

(void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
    // Creates a mutable data object for updating with binary data, like a byte array
    NSMutableData *pdfData = [NSMutableData data];

    // Points the pdf converter to the mutable data object and to the UIView to be converted
    UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
    UIGraphicsBeginPDFPage();
    CGContextRef pdfContext = UIGraphicsGetCurrentContext();


    // draws rect to the view and thus this is captured by UIGraphicsBeginPDFContextToData

    [aView.layer renderInContext:pdfContext];

    // remove PDF rendering context
    UIGraphicsEndPDFContext();

    // Retrieves the document directories from the iOS device
    NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);

    NSString* documentDirectory = [documentDirectories objectAtIndex:0];
    NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];

    // instructs the mutable data object to write its context to a file on disk
    [pdfData writeToFile:documentDirectoryFilename atomically:YES];
    NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);
}

还要确保导入:QuartzCore/QuartzCore.h

Answer 2

另外,如果有人有兴趣,这里是Swift 3代码:

func createPdfFromView(aView: UIView, saveToDocumentsWithFileName fileName: String)
{
    let pdfData = NSMutableData()
    UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil)
    UIGraphicsBeginPDFPage()

    guard let pdfContext = UIGraphicsGetCurrentContext() else { return }

    aView.layer.render(in: pdfContext)
    UIGraphicsEndPDFContext()

    if let documentDirectories = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first {
        let documentsFileName = documentDirectories + "/" + fileName
        debugPrint(documentsFileName)
        pdfData.write(toFile: documentsFileName, atomically: true)
    }
}

Answer 3

如果有人有兴趣,这里是Swift 2.1代码:

    func createPdfFromView(aView: UIView, saveToDocumentsWithFileName fileName: String)
    {
        let pdfData = NSMutableData()
        UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil)
        UIGraphicsBeginPDFPage()

        guard let pdfContext = UIGraphicsGetCurrentContext() else { return }

        aView.layer.renderInContext(pdfContext)
        UIGraphicsEndPDFContext()

        if let documentDirectories = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).first {
            let documentsFileName = documentDirectories + "/" + fileName
            debugPrint(documentsFileName)
            pdfData.writeToFile(documentsFileName, atomically: true)
        }
    }

Answer 4

从 UIView 创建 PDF 的一种超级简单的方法是使用 UIView 扩展

斯威夫特 4.2

extension UIView {

  // Export pdf from Save pdf in drectory and return pdf file path
  func exportAsPdfFromView() -> String {

      let pdfPageFrame = self.bounds
      let pdfData = NSMutableData()
      UIGraphicsBeginPDFContextToData(pdfData, pdfPageFrame, nil)
      UIGraphicsBeginPDFPageWithInfo(pdfPageFrame, nil)
      guard let pdfContext = UIGraphicsGetCurrentContext() else { return "" }
      self.layer.render(in: pdfContext)
      UIGraphicsEndPDFContext()
      return self.saveViewPdf(data: pdfData)

  }

  // Save pdf file in document directory
  func saveViewPdf(data: NSMutableData) -> String {  
    let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
    let docDirectoryPath = paths[0]
    let pdfPath = docDirectoryPath.appendingPathComponent("viewPdf.pdf")
    if data.write(to: pdfPath, atomically: true) {
        return pdfPath.path
    } else {
        return ""
    }
  }
}

信用：http : //www.swiftdevcenter.com/create-pdf-from-uiview-wkwebview-and-uitableview/

Answer 5

使用 Swift 5 / iOS 12，您可以将CALayer的render(in:)方法与UIGraphicsPDFRenderer的writePDF(to:withActions:)方法结合起来，以便从UIView实例创建 PDF 文件。

以下 Playground 示例代码展示了如何使用render(in:)和writePDF(to:withActions:)：

import UIKit
import PlaygroundSupport

let view = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
view.backgroundColor = .orange
let subView = UIView(frame: CGRect(x: 20, y: 20, width: 40, height: 60))
subView.backgroundColor = .magenta
view.addSubview(subView)

let outputFileURL = PlaygroundSupport.playgroundSharedDataDirectory.appendingPathComponent("MyPDF.pdf")
let pdfRenderer = UIGraphicsPDFRenderer(bounds: view.bounds)

do {
    try pdfRenderer.writePDF(to: outputFileURL, withActions: { context in
        context.beginPage()
        view.layer.render(in: context.cgContext)
    })
} catch {
    print("Could not create PDF file: \(error)")
}

注意：为了playgroundSharedDataDirectory在 Playground 中使用，您首先需要在 macOS“Documents”文件夹中创建一个名为“Shared Playground Data”的文件夹。

下面的子UIViewController类完整实现显示了为 iOS 应用程序重构前面示例的可能方法：

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let view = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
        view.backgroundColor = .orange
        let subView = UIView(frame: CGRect(x: 20, y: 20, width: 40, height: 60))
        subView.backgroundColor = .magenta
        view.addSubview(subView)

        createPDF(from: view)
    }

    func createPDF(from view: UIView) {
        let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        let outputFileURL = documentDirectory.appendingPathComponent("MyPDF.pdf")
        print("URL:", outputFileURL) // When running on simulator, use the given path to retrieve the PDF file

        let pdfRenderer = UIGraphicsPDFRenderer(bounds: view.bounds)

        do {
            try pdfRenderer.writePDF(to: outputFileURL, withActions: { context in
                context.beginPage()
                view.layer.render(in: context.cgContext)
            })
        } catch {
            print("Could not create PDF file: \(error)")
        }
    }

}