ipad - HelloWorld How To View a PDF

I need to write a simple 开发者_运维问答app which will view a PDF stored locally on the phone as part of the app bundle.

Is there a control in UIBuilder that I can use to display a PDF?

UIWebView will load PDFs, as well as several other file formats. See Using UIWebView to display select document types.

To view a PDF as a UIImage, where the source of the PDF is a Base64 string, use this simple class. (MonoTouch)

using System;
using MonoTouch.UIKit;
using MonoTouch.Foundation;
using System.Drawing;
using MonoTouch.CoreGraphics;
using System.IO;
namespace Common
{
    public class PDF
    {

        public static readonly string MyDocuments = Environment.GetFolderPath (Environment.SpecialFolder.Personal);

        public static string SavePDFReturnPath (string Base64PDFString, string FileName)
        {

            string path = Path.Combine (MyDocuments, "pdfs");
            if (!Directory.Exists (path))
                Directory.CreateDirectory (path);

            FileName = FileName.ToLower ();
            if (!FileName.EndsWith ("pdf"))
                FileName = FileName + ".pdf";

            path = Path.Combine (path, FileName);
            if (File.Exists (path))
                File.Delete (path);

            using (var f = System.IO.File.Create (path))
            {
                byte[] encodedDataAsBytes = System.Convert.FromBase64String (Base64PDFString);
                f.Write (encodedDataAsBytes, 0, encodedDataAsBytes.Length);
            }

            return path;
        }

        public static UIImage GetImageFromPDFThatIsInBase64 (string Base64PDFString)
        {
            RectangleF PDFRectangle = new RectangleF (0, 0, UIScreen.MainScreen.Bounds.Width, UIScreen.MainScreen.Bounds.Height);
            return GetImageFromPDFThatIsInBase64 (Base64PDFString, PDFRectangle);
        }


        public static UIImage GetImageFromPDFThatIsInBase64 (string Base64PDFString, RectangleF PDFRectangle)
        {
            UIImage img = null;

            try
            {
                UIGraphics.BeginImageContext (new SizeF (PDFRectangle.Width, PDFRectangle.Height));
                CGContext context = UIGraphics.GetCurrentContext ();
                context.SaveState ();

                CGPDFDocument pdfDoc = CGPDFDocument.FromFile (SavePDFReturnPath (Base64PDFString, "temp.pdf"));
                CGPDFPage pdfPage = pdfDoc.GetPage (1);

                img = TransformPDFToImage (pdfPage, PDFRectangle.Width);

                pdfDoc.Dispose ();
                context.RestoreState ();

                UIGraphics.EndImageContext ();
            }
            catch (Exception e)
            {
                Console.WriteLine ("GetImageFromBase64PDFImage: {0}", e.Message);
            }
            return img;

        }

        private static UIImage TransformPDFToImage (CGPDFPage page, Single width)
        {
            RectangleF pageRect = page.GetBoxRect (CGPDFBox.Media);

            Single pdfScale = width / pageRect.Size.Width;
            pageRect.Size = new SizeF (pageRect.Size.Width * pdfScale, pageRect.Size.Height * pdfScale);
            //pageRect.Origin = CGPointZero;

            UIGraphics.BeginImageContext (pageRect.Size);
            CGContext context = UIGraphics.GetCurrentContext ();

            //White BG
            context.SetRGBFillColor (1.0f, 1.0f, 1.0f, 1.0f);
            context.FillRect (pageRect);
            context.SaveState ();

            // Next 3 lines makes the rotations so that the page look in the right direction
            context.TranslateCTM (0.0f, pageRect.Size.Height);
            context.ScaleCTM (1.0f, -1.0f);
            CGAffineTransform transform = page.GetDrawingTransform (CGPDFBox.Media, pageRect, 0, true);
            context.ConcatCTM (transform);

            context.DrawPDFPage (page);
            context.RestoreState ();

            UIImage img = UIGraphics.GetImageFromCurrentImageContext ();
            UIGraphics.EndImageContext ();

            return img;
        }
    }
}