Question

I’m new to MonoTouch development and I would like to embed some PDF Viewing functionality in my app. I have found several resources for doing that, however, I also see enough remarks about all the additional implementations to make it stable and fast.

I now see that there is a good ObjectiveC library which already implements a lot of functionality (CATiledLayer, multi-threading, page scrolling, thumb nails, device rotation …): https://github.com/vfr/Reader

The last days, after reading the monotoch binding documentation, I’m trying to bind this in MonoTouch, but without success.
I’m able to export it to a library (.a) file and I’ve created a binding API.

    //@interface ReaderDocument : NSObject <NSObject, NSCoding>
    [BaseType (typeof (NSObject))]
    interface ReaderDocument {

    //- (id)initWithFilePath:(NSString *)fullFilePath password:(NSString *)phrase;
    [Export("initWithFilePath:password")]
    IntPtr Constructor (string path, string phrase);

    //Properties
    [Export("guid")]
    string Guid { get;}

    [Export("fileDate")]
    NSDate FileDate { get;}

    [Export("lastOpen")]
    NSDate LastOpen { get;set;}

    [Export("fileSize")]
    NSNumber FileSize{ get;}

    [Export("pageCount")]
    NSNumber PageCount { get;}

    [Export("pageNumber")]
    NSNumber PageNumber { get;set;}

    [Export("bookmarks")]
    NSMutableIndexSet Bookmarks { get;}

    [Export("fileName")]
    string FileName { get;}

    [Export("password")]
    string Password { get;}

    [Export("fileURL")]
    NSUrl FileURL { get;}

    //Methods

    //+ (ReaderDocument *)withDocumentFilePath:(NSString *)filename password:(NSString *)phrase;
    [Static, Export("withDocumentFilePath:password")]
    ReaderDocument WithDocumentFilePath(string filename, string phrase);

    //+ (ReaderDocument *)unarchiveFromFileName:(NSString *)filename password:(NSString *)phrase;
    [Static, Export("unarchiveFromFileName:password")]
    ReaderDocument UnarchiveFromFileName(string filename, string phrase);

    //- (void)saveReaderDocument;
    [Export("saveReaderDocument")]
    void SaveReaderDocument();

    //- (void)updateProperties;
    [Export("updateProperties")]
    void updateProperties();
}

I’m very unsure about following line btw:

//@interface ReaderDocument : NSObject <NSObject, NSCoding>
    [BaseType (typeof (NSObject))]
    interface ReaderDocument

Not sure if I have to do something with the “”?

I can now create following code in MonoTouch

ReaderDocument doc =  ReaderDocument.withDocumentFilePath("Tamarin.pdf","");

or

ReaderDocument doc = new ReaderDocument("Tamarin.pdf","yrt");

Both are resulting in “unrecognized selector” error

  2012-11-04 22:15:05.731 PFDTest1[4149:1507] +[ReaderDocument withDocumentFilePath:password]: unrecognized selector sent to class 0x2f7738

[ERROR] FATAL UNHANDLED EXCEPTION: MonoTouch.Foundation.MonoTouchException: Objective-C     exception thrown.  Name: NSInvalidArgumentException Reason: +[ReaderDocument   withDocumentFilePath:password]: unrecognized selector sent to class 0x2f7738
at (wrapper managed-to-native)   MonoTouch.ObjCRuntime.Messaging:IntPtr_objc_msgSend_IntPtr_IntPtr   (intptr,intptr,intptr,intptr)
at VFRBinding4.ReaderDocument.withDocumentFilePath (System.String filename,  System.String phrase) [0x00000] in <filename unknown>:0 
at PFDTest1.AppDelegate.FinishedLaunching (MonoTouch.UIKit.UIApplication app, MonoTouch.Foundation.NSDictionary options) [0x00030] in /Users/matthiasvalcke/Projects/PFDTest1/PFDTest1/AppDelegate.cs:39 
at (wrapper managed-to-native) MonoTouch.UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
at MonoTouch.UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x0004c] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:38 
at PFDTest1.Application.Main (System.String[] args) [0x00000] in  /Users/matthiasvalcke/Projects/PFDTest1/PFDTest1/Main.cs:17 

Any ideas?

Answer 1

There could be other issues but your bindings are wrong for the constructors, i.e.

//- (id)initWithFilePath:(NSString *)fullFilePath password:(NSString *)phrase;
[Export("initWithFilePath:password")]
void InitWithFilePath(string path, string password);

ObjectiveC init* selectors should be binded as C# constructors. E.g.

[Export("initWithFilePath:password")]
IntPtr Constructor (string path, string password);

and that should be what you use to create the instance, e.g.

ReaderDocument doc = new ReaderDocument ("sample.pdf", "");
// ...