ios如何实现内部购买的方法

//一、导入MKStore的包在需要触发下载的地方写一个 弹出提示框UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"网络连接异常，下载失败"                                                                 message:@"请重新点击下载"                                                                delegate:self                                                       cancelButtonTitle:@"确定"                                                      otherButtonTitles:nil, nil];            [alertView show];            [alertView release];            alertView = nil;   //点击确定的时候就会回调 实现代理的方法，触发buyAction 这个方法。/** 购买操作 */- (void) buyAction{NSString *pid = PRODUCT_ID;    NSMutableArray * array = [NSMutableArray arrayWithCapacity:0];    [array addObject:pid];    [[MKStoreManager sharedManager] requestProductData:array];[MKStoreManager sharedManager].delegate = self;}#pragma mark MKStoreManager Delegate Method- (void)didRequestProductData:(NSArray *)skProducts {//NSLog(@"paying......0 ");if (skProducts == nil || [skProducts count] == 0) {return;}SKProduct *product = [skProducts objectAtIndex:0];    NSLog(@"product is %@",product);SKPayment *pay = [SKPayment paymentWithProductIdentifier:[product productIdentifier]];[[SKPaymentQueue defaultQueue] addPayment:pay];//NSLog(@"paying......");}/** 验证AppStore数据信息 */- (void)finishedTransactionWithState:(TransactionState)state {        NSString *message = nil;  //提示信息        switch (state) {        case TransactionPurchasing:             message = [NSString stringWithString: @"支付操作进行中...!"];            break;        case TransactionCompleted:            message = [NSString stringWithString: @"支付成功...!"];            NSUserDefaults * ud = [NSUserDefaults standardUserDefaults];            [ud setObject:@"1" forKey:@"isbuy"];            break;        case TransactionRestored:            message = [NSString stringWithString: @"恢复支付操作!"];            break;        case TransactionFailed:            message = [NSString stringWithString: @"支付失败!"];            break;        default:            break;    }//[Utils alertWithTitle: @"支付" message: message];}- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{    if(buttonIndex == 1){        [self buyAction];    }}