How to Convert UIView to PDF within iOS?
There are a lot of resources about how to display a PDF in an App's UIView. What I am working on now is to create a PDF from UIViews. 
For example, I have a UIView, with subviews like Textviews, UILabels, UIImages, so how can I convert a big UIView as a whole including all its subviews and subsubviews to a PDF?
I have checked Apple's iOS reference. However, it only talks about writing pieces of text/image to a PDF file.
The problem I am facing is that the content I want to write to a file as PDF is a lot. If I write them to the PDF piece by piece, it is going to be huge work to do.
That's why I am looking for a way to write UIViews to PDFs or even bitmaps.
I have tried the source code I copied from other Q/A within Stack Overflow. But it only gives me a blank PDF with the UIView bounds size.
-(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 = [documentDi开发者_Go百科rectory stringByAppendingPathComponent:aFilename];
    // instructs the mutable data object to write its context to a file on disk
    [pdfData writeToFile:documentDirectoryFilename atomically:YES];
    NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);
}
Note that the following method creates just a bitmap of the view; it does not create actual typography.
(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);
}
Also make sure you import: QuartzCore/QuartzCore.h
Additionally, if anyone is interested, here is the Swift 3 code:
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)
    }
}
If someone is interested, here's Swift 2.1 code:
    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)
        }
    }
A super easy way to create a PDF from UIView is using UIView Extension
Swift 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 ""
    }
  }
}
Credit: http://www.swiftdevcenter.com/create-pdf-from-uiview-wkwebview-and-uitableview/
With Swift 5 / iOS 12,  you can combine CALayer's render(in:) method with UIGraphicsPDFRenderer's writePDF(to:withActions:) method in order to create a PDF file from a UIView instance.
The following Playground sample code shows how to use render(in:) and 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)")
}
Note: in order to use playgroundSharedDataDirectory in your Playground, you first need to create a folder called "Shared Playground Data" in you macOS "Documents" folder.
The UIViewController subclass complete implementation below shows a possible way to refactor the previous example for an iOS app:
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)")
        }
    }
}
This will generate PDF from UIView and open print dialog, objective C.
Attach - (IBAction)PrintPDF:(id)sender to your button on screen.
Add #import <QuartzCore/QuartzCore.h> framework
H File
    @interface YourViewController : UIViewController <MFMailComposeViewControllerDelegate,UIPrintInteractionControllerDelegate>
    {
    UIPrintInteractionController *printController;
    }
- (IBAction)PrintPDF:(id)sender;
M File
-(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];
    }
}
I don't know why, but casilic's answer gives me blank screen on iOS6.1. The code below works.
-(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;
}
 
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