In-App Purchase Programming Guide - Apple Developer

Delivering Products
Waiting for the App Store to Process Transactions
launched, Store Kit calls your transaction queue observer again and delivers the purchased content at that
time. Similarly, if your app fails to mark a transaction as finished, Store Kit calls the observer every time your
app is launched until the transaction is properly finished.
Listing 4-1
Registering the transaction queue observer
- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
/* ... */
}
[[SKPaymentQueue defaultQueue] addTransactionObserver:observer];
Implement the paymentQueue:updatedTransactions: method on your transaction queue observer. Store
Kit calls this method when the status of a transaction changes—for example, when a payment request has
been processed. The transaction status tells you what action your app needs to perform, as shown in Table
4-1 and Listing 4-2.
Table 4-1
Status
Transaction statuses and corresponding actions
Action to take in your app
SKPaymentTransactionStatePurchasing
SKPaymentTransactionStateFailed
SKPaymentTransactionStatePurchased
SKPaymentTransactionStateRestored
Update your UI to reflect the status, and wait to be
called again.
Use the value of the error property to present a
message to the user.
Provide the purchased functionality.
Restore the previously purchased functionality.
Listing 4-2
Responding to transaction statuses
- (void)paymentQueue:(SKPaymentQueue *)queue
updatedTransactions:(NSArray *)transactions
{
for (SKPaymentTransaction *transaction in transactions) {
switch (transaction.transactionState) {
2013-10-22 | Copyright © 2013 Apple Inc. All Rights Reserved.
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