如何在 iOS 中将 UIView 转换为 PDF？

Question

有很多关于如何在应用程序的UIView 中显示 PDF 的资源。我现在正在做的是从UIViews 创建一个 PDF。

例如，我有一个UIView，有像 Textviews、UILabels、UIImages 这样的子视图，那么如何将一个 big UIView 转换为一个整体，包括它的所有子视图以及 PDF 的子视图？

我已经检查了Apple's iOS reference。但是，它只涉及将文本/图像写入 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，这将是一项巨大的工作。 这就是为什么我正在寻找一种将UIViews 写入 PDF 甚至位图的方法。

我已经尝试过从 Stack Overflow 的其他问答中复制的源代码。但它只给了我一个空白 PDF，其边界大小为 UIView。

-(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);
}

Answer 1

请注意，以下方法创建的只是视图的位图；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，如果有人感兴趣，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

如果有人感兴趣，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:) 方法结合使用，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：为了在您的 Playground 中使用 playgroundSharedDataDirectory，您首先需要在 macOS 的“Documents”文件夹中创建一个名为“Shared Playground Data”的文件夹。

---

下面的UIViewController 子类完整实现展示了一种为iOS 应用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)")
        }
    }

}

Answer 6

这将从 UIView 生成 PDF 并打开打印对话框，目标 C。 将- (IBAction)PrintPDF:(id)sender 附加到屏幕上的按钮。 添加#import <QuartzCore/QuartzCore.h>框架

H 文件

    @interface YourViewController : UIViewController <MFMailComposeViewControllerDelegate,UIPrintInteractionControllerDelegate>

    {
    UIPrintInteractionController *printController;
    }

- (IBAction)PrintPDF:(id)sender;

M 文件

-(void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename

{
    NSMutableData *pdfData = [NSMutableData data];

    UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
    UIGraphicsBeginPDFPage();
    CGContextRef pdfContext = UIGraphicsGetCurrentContext();


    [aView.layer renderInContext:pdfContext];
    UIGraphicsEndPDFContext();

    NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);

    NSString* documentDirectory = [documentDirectories objectAtIndex:0];
    NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
    NSString *file = [documentDirectory stringByAppendingPathComponent:@"yourPDF.pdf"];
    NSURL *urlPdf = [NSURL fileURLWithPath: file];

    [pdfData writeToFile:documentDirectoryFilename atomically:YES];
    NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);

}


- (IBAction)PrintPDF:(id)sender
{
    [self createPDFfromUIView:self.view saveToDocumentsWithFileName:@"yourPDF.pdf"];

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:@"yourPDF.pdf"];
    NSData *myData = [NSData dataWithContentsOfFile: path];

    UIPrintInteractionController *pic = [UIPrintInteractionController sharedPrintController];
    if(pic && [UIPrintInteractionController canPrintData: myData] ) {

        pic.delegate = self;

        UIPrintInfo *printInfo = [UIPrintInfo printInfo];
        printInfo.outputType = UIPrintInfoOutputGeneral;
        printInfo.jobName = [path lastPathComponent];
        printInfo.duplex = UIPrintInfoDuplexLongEdge;
        pic.printInfo = printInfo;
        pic.showsPageRange = YES;
        pic.printingItem = myData;

        void (^completionHandler)(UIPrintInteractionController *, BOOL, NSError *) = ^(UIPrintInteractionController *pic, BOOL completed, NSError *error) {
            //self.content = nil;
            if(!completed && error){

                NSLog(@"Print Error: %@", error);
            }
        };

        [pic presentAnimated:YES completionHandler:completionHandler];

    }

}

Answer 7

我不知道为什么，但 casilic 的回答让我在 iOS6.1 上出现黑屏。下面的代码有效。

-(NSMutableData *)createPDFDatafromUIView:(UIView*)aView 
{
    // 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();

    return pdfData;
}


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

    // 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);
    return documentDirectoryFilename;
}