Nicholas Hart questions

Nicholas Hart answers

• Accessing the objectID of a NSManagedObject on a different thread?
• Hiding UICollectionViewCell
• UITableViewController changing one reusable cell affects other cells
• Call back url for iOS app?
• -ObjC linker flag causes duplicate symbol errors
• ARC and UIAlertView: unrecognized selector sent to instance
• iOS auto renewing subscription (sandbox)