Objective-C delegate incompatible type - objective-c

Question

I am using http://www.vfr.org/, pdf viewer, and I try to add a button to open PDF in IBOOK.
I added the button and action to it, but I stuck t the moment when I want open ibooks application with this pdf.
I tried 2 solutions:
button tapped action:
NSURL *fileURL = document.fileURL;
NSString *fileName = document.fileName; // Document
[[UIApplication sharedApplication] openURL:fileURL];
It opens the IBOOKS but the PDF never gets loaded.
I am assuming the URL format can be wrong I tried even hard code a PDF URL like:
NSString *stringURL = #"itms-books://linktopdf.pdf";
NSURL *url = [NSURL URLWithString:stringURL];
[[UIApplication sharedApplication] openURL:url];
But the same result.
2) Button tapped action:
NSURL *fileURL = document.fileURL;
NSString *fileName = document.fileName; // Document
UIDocumentInteractionController *docController = [[UIDocumentInteractionController alloc] init];
docController = [UIDocumentInteractionController interactionControllerWithURL:fileURL];
docController.delegate = self;
But I have an warning where I try to delegate: docController.delegate = self;
assigning to id UIDocumentInteractionControllerDelegate from Incompatible ReaderViewController
Can someone help me to make it work at least 1 of these solution.

Answer 1

Has the ReaderViewController this kind of line in the header file: #interface ReaderViewController : NSObject < UIDocumentInteractionControllerDelegate > ?

Answer 2

Your class must conform to the UIDocumentInteractionControllerDelegate protocol, so in your .h file make it look like
#interface ReaderViewController : PerantClass <UIDocumentInteractionControllerDelegate>
{
...
}
Then the compiler will know that your class conforms to that protocol. Of course, you still need to implement the needed methods.
ALso Check this Link - 1 And Link - 2.