Import AppDelegate.h into DropView.m, and call the method you want to run from the performDragOperation: method.
-(BOOL)performDragOperation:(id<NSDraggingInfo>)sender{
NSPasteboard* prb;
prb= [sender draggingPasteboard];
draggedFilePaths = [prb propertyListForType:NSFilenamesPboardType];
[(AppDelegate *)[[NSApplication sharedApplication]delegate] doWhatever:draggedFilePaths];
return YES;
}
Where doWhatever: is a method implemented in the app delegate.