You can determine whether a user has selected "Done" via the UIDocumentInteractionController's delegate. Simply:
@interface MyClass : NSObject <UIDocumentInteractionControllerDelegate>
...
@end
...
UIDocumentInteractionController* controller = ...;
controller.delegate = self;
...
- (void)documentInteractionControllerDidEndPreview:(UIDocumentInteractionController *)controller
{
NSLog(@"User has dismissed preview");
}
As for removing "Share", this isn't easy, and Apple suggest you should have it in all cases. This makes sense, if you're previewing a PDF, the user may very well wish to view it in a dedicated PDF reader, or to email it. If you don't want the ability to share due to business/security reasons, then you'll need to try and render the document yourself. How this is done depends on the document,