Question

I don’t really understand this idea.
Do I have to provide a restore button for the user?
What method should this method invoke?
What will restore will do?

Answer 1

You typically restore purchases with this code:

[[SKPaymentQueue defaultQueue] restoreCompletedTransactions];

It will reinvoke -paymentQueue:updatedTransactions on the observer(s) for the purchased items. This is useful for users who reinstall the app after deletion or install it on a different device.

Not all types of In-App purchases can be restored.