我的应用支持应用内购买和自动续订订阅，因此每当系统发布续订通知时，SKPaymentTransactionObserver 都会得到适当的通知，这一点很重要。
我更喜欢将我的 StoreKit 代码与 AppDelegate 分开，所以我为它创建了一个单例，并在 AppDelegate 中引用。
class AppDelegate: UIResponder, UIApplicationDelegate {
let storeKitManager = DFStoreKitManager.shared
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
storeKitManager.register()
//...
return true
}
func applicationWillTerminate(_ application: UIApplication) {
storeKitManager.deregister()
}
}
我将共享实例添加为 SKPaymentQueue 的观察者。
class DFStoreKitManager: NSObject {
static let shared = DFStoreKitManager()
private override init() { //This prevents other classes from using the default '()' initializer for this class.
super.init()
}
func register() {
SKPaymentQueue.default().add(self)
}
func deregister() {
SKPaymentQueue.default().remove(self)
}
//...
}
extension DFStoreKitManager: SKPaymentTransactionObserver {
func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
for tx in transactions {
switch tx.transactionState {
case .purchasing: print("SKPaymentTransaction purchasing")
case .deferred: print("SKPaymentTransaction deferred")
case .failed: print("SKPaymentTransaction failed")
//...
queue.finishTransaction(tx)
case .restored: print("SKPaymentTransaction restored")
//...
queue.finishTransaction(tx)
case .purchased: print("SKPaymentTransaction purchased")
//...
queue.finishTransaction(tx)
}
}
}
func paymentQueue(_ queue: SKPaymentQueue, removedTransactions transactions: [SKPaymentTransaction]) {
print("Removed \(transactions.count) StoreKit transactions")
}
func paymentQueue(_ queue: SKPaymentQueue, restoreCompletedTransactionsFailedWithError error: Error) {
print("SKPaymentTransaction failed to restore through SKPaymentQueue: \(error.localizedDescription)")
}
}
我的日志和分析显示，续订一直是通过观察者队列处理的，但这个数字似乎明显低于 iTunes Connect 中显示的实际续订数量。
从 iOS 9 开始，NSNotificationCenter 将自动停止向已被释放的观察者发送通知(source)。
所以我想知道，是否有可能我的单例正在被系统释放，以便 SKPaymentTransactionObersver 也被删除？
或者这个单例(及其观察者状态)是否保证保留到应用程序终止？
最佳答案
SKPaymentQueue/SKPaymentTransactionObserver 文档，具体来说，状态:
// Observers are not retained. The transactions array will only be synchronized with the server while the queue has observers. This may require that the user authenticate.
open func add(_ observer: SKPaymentTransactionObserver)
open func remove(_ observer: SKPaymentTransactionObserver)
关于ios - 观察者是否被 Swift 单例永久保留？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43851737/