iphone - 如何通过 NSNotification 将消息从一个类传递到另一个类

Question

Ha-ii，我正在我的应用程序中进行应用内购买，当应用内内容购买成功时我需要禁用一个按钮，所以我将 NSuserdefault 放入我的代码中以确定是否成功，但是NSUserDefault仅在我刷新页面时有效，当内容成功消息出现时我没有启用按钮，当我返回另一个页面并返回时我被启用，我需要通过通知将实例消息传递给viewcontroller .我的代码是

- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions {
    for(SKPaymentTransaction *transaction in transactions) {
        switch (transaction.transactionState) {

            case SKPaymentTransactionStatePurchasing:
                // Item is still in the process of being purchased
                break;

            case SKPaymentTransactionStatePurchased:
                // Item was successfully purchased!

                // --- UNLOCK FEATURE OR DOWNLOAD CONTENT HERE ---
                // The purchased item ID is accessible via 
                // transaction.payment.productIdentifier

                // After customer has successfully received purchased content,
                // remove the finished transaction from the payment queue.
                [[SKPaymentQueue defaultQueue] finishTransaction: transaction];
                 [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"Transsucess"];
                break;

            case SKPaymentTransactionStateRestored:
                // Verified that user has already paid for this item.
                // Ideal for restoring item across all devices of this customer.

                // --- UNLOCK FEATURE OR DOWNLOAD CONTENT HERE ---
                // The purchased item ID is accessible via 
                // transaction.payment.productIdentifier

                // After customer has restored purchased content on this device,
                // remove the finished transaction from the payment queue.
                [[SKPaymentQueue defaultQueue] finishTransaction: transaction];
                break;

            case SKPaymentTransactionStateFailed:
                // Purchase was either cancelled by user or an error occurred.

                if (transaction.error.code != SKErrorPaymentCancelled) {
                    // A transaction error occurred, so notify user.
                [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"Transsucess"];
                }
                // Finished transactions should be removed from the payment queue.
                [[SKPaymentQueue defaultQueue] finishTransaction: 

transaction];
                break;
        }
    }
}

在我的 anothervierwcontroller 中，我想传递 Nsuserdefault 值的 Notification 值。如何做到这一点。请帮助我。

Answer 1

在您的第一个 View vieDidLoad 中添加行 ..

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(ContentPurchased) name:@"Purchased" object:nil];

(在 dealloc 中移除观察者)

然后当您在问题代码中购买成功时..发布通知

[[NSNotificationCenter defaultCenter] postNotificationName:@"Purchased"  object:nil userInfo:nil];

您可以传递对象..但我相信您应该将购买交易详细信息存储在NSUserdefautls..因为下次运行应用程序时需要它..

当您发布时，通知 ContentPurchased 方法在第一个 View 中被调用(您必须在 View Controller 中添加它)