iOS应用内付费(IAP)开发步骤列表

if ([SKPaymentQueue canMakePayments]) {  
    // 执行下面提到的第5步：  
    [self getProductInfo];  
} else {  
    NSLog(@"失败，用户禁止应用内付费购买.");  
}  

// 下面的ProductId应该是事先在itunesConnect中添加好的，已存在的付费项目。否则查询会失败。  
- (void)getProductInfo {  
	NSSet * set = [NSSet setWithArray:@[@"ProductId"]];  
	SKProductsRequest * request = [[SKProductsRequest alloc] initWithProductIdentifiers:set];  
	request.delegate = self;  
	[request start];  
}  
// 以上查询的回调函数  
- (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response {  
    NSArray *myProduct = response.products;  
    if (myProduct.count == 0) {  
        NSLog(@"无法获取产品信息，购买失败。");  
        return;  
    }  
    SKPayment * payment = [SKPayment paymentWithProduct:myProduct[0]];  
    [[SKPaymentQueue defaultQueue] addPayment:payment];  
}  

- (void)viewDidLoad {  
    [super viewDidLoad];  

    // 监听购买结果  
    [[SKPaymentQueue defaultQueue] addTransactionObserver:self];  
}  
- (void)viewDidUnload {  
    [super viewDidUnload];  
    [[SKPaymentQueue defaultQueue] removeTransactionObserver:self];  
}  

- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions {  
    for (SKPaymentTransaction *transaction in transactions)  
    {  
        switch (transaction.transactionState)  
        {  
            case SKPaymentTransactionStatePurchased://交易完成  
                NSLog(@"transactionIdentifier = %@", transaction.transactionIdentifier);  
                [self completeTransaction:transaction];  
                break;  
            case SKPaymentTransactionStateFailed://交易失败  
                [self failedTransaction:transaction];  
                break;  
            case SKPaymentTransactionStateRestored://已经购买过该商品  
                            [self restoreTransaction:transaction];  
                            break;  
                        case SKPaymentTransactionStatePurchasing:      //商品添加进列表  
                            NSLog(@"商品添加进列表");  
                            break;  
                        default:  
                            break;  
                    }  
                }  
            }  
            - (void)completeTransaction:(SKPaymentTransaction *)transaction {  
                // Your application should implement these two methods.  
                NSString * productIdentifier = transaction.payment.productIdentifier;  
                NSString * receipt = [transaction.transactionReceipt base64EncodedString];  
                if ([productIdentifier length] > 0) {  
                    // 向自己的服务器验证购买凭证  
                }  
                // Remove the transaction from the payment queue.  
                [[SKPaymentQueue defaultQueue] finishTransaction: transaction];  
            }  
            - (void)failedTransaction:(SKPaymentTransaction *)transaction {  
                if(transaction.error.code != SKErrorPaymentCancelled) {  
                    NSLog(@"购买失败");  
                } else {  
                    NSLog(@"用户取消交易");  
                }  
                [[SKPaymentQueue defaultQueue] finishTransaction: transaction];  
            }  
            - (void)restoreTransaction:(SKPaymentTransaction *)transaction {  
            	// 对于已购商品，处理恢复购买的逻辑  
                [[SKPaymentQueue defaultQueue] finishTransaction: transaction];  
            }