Restore InApp purchase using swift, iOS

Question

I am implementing restore in app purchase. I have a button whose action is

@IBAction func restorePurchases(send : AnyObject){

SKPaymentQueue.defaultQueue().restoreCompletedTransactions()
// if (success) { 
// I want to do something here      
// }
}

My question is.

1. Is this the right way to restore?
2. How can we verify success action for restoring purchases?

Answer 1

don't forget to check if you can make a payment:

if (SKPaymentQueue.canMakePayments()) {
  SKPaymentQueue.default().restoreCompletedTransactions()
}

for check if the restore was good you have to follow the protocol: SKPaymentTransactionObserver and then implement the method:

func paymentQueue(queue: SKPaymentQueue!, updatedTransactions transactions: [AnyObject]!)

and subscribe to the event by doing:

SKPaymentQueue.default().add(self)

Finally here is an exemple of how I check the result:

func paymentQueue(_ queue: SKPaymentQueue!, updatedTransactions transactions: [AnyObject]!)    {
  print("Received Payment Transaction Response from Apple");
  for transaction in transactions {
    switch transaction.transactionState {
    case .purchased, .restored:
      print("Purchased purchase/restored")
      SKPaymentQueue.default().finishTransaction(transaction as SKPaymentTransaction)
      break
    case .failed:
      print("Purchased Failed")
      SKPaymentQueue.default().finishTransaction(transaction as SKPaymentTransaction)
      break
    default:
      print("default")
      break
    }
  }
}