苹果内购 (无力吐槽,暂时先这样),说说它里面的关键步骤.

• 添加收款银行卡 和 商品 :https://www.jianshu.com/p/1e6b1152afc6
• 创建沙盒 测试账号 : https://www.jianshu.com/p/143b410ff09a
• 代码部分

大致 方向是 product_id => Payment =>唤起苹果支付

通过 主要是 `SKPaymentTransactionObserver`(观察支付状态) 和 
`SKProductsRequestDelegate` (通过商品id去苹果服务器获取商品信息)
为了方便的开发 我自己封装了 ApplePay

#import "ApplePay.h"
//沙盒测试环境验证
#define ApplePayWithSandBoxUrl  @"https://sandbox.itunes.apple.com/verifyReceipt"
//正式环境验证
#define ApplePayWithAppStoreUrl @"https://buy.itunes.apple.com/verifyReceipt"


@interface ZLApplePay () <SKPaymentTransactionObserver,SKProductsRequestDelegate>

@property (nonatomic,copy) NSString * currentProductId;
//@property (nonatomic,strong) NSDictionary * mapDic;//product_id -> 金额的映射
@property (nonatomic,weak) id <ZLApplePayDelegate> delegate;


@end

@implementation ZLApplePay

LEE_SINGLE_M //单例


- (void)dealloc {
    [self removeObserver];
}

- (instancetype)init {
    if (self = [super init]) {
        [self addObserver];
    }
    return self;
}

- (void)addObserver {

    [self removeObserver];
    //添加一个交易队列观察者
    [[SKPaymentQueue defaultQueue] addTransactionObserver:self];
}

- (void)removeObserver {
    //添加一个交易队列观察者
    [[SKPaymentQueue defaultQueue] removeTransactionObserver:self];
}


#pragma mark - private

/**
 *  验证购买，避免越狱软件模拟苹果请求达到非法购买问题
    暂时不做
 *
 */
-(void)verifyPurchase {

    //从沙盒中获取交易凭证并且拼接成请求体数据
    NSURL *receiptUrl=[[NSBundle mainBundle] appStoreReceiptURL];
    NSData *receiptData=[NSData dataWithContentsOfURL:receiptUrl];
    NSString *receiptString=[receiptData base64EncodedStringWithOptions:NSDataBase64EncodingEndLineWithLineFeed];//转化为base64字符串
    NSString *bodyString = [NSString stringWithFormat:@"{\"receipt-data\" : \"%@\"}", receiptString];//拼接请求数据
    NSData *bodyData = [bodyString dataUsingEncoding:NSUTF8StringEncoding];
    //创建请求到苹果官方进行购买验证
    NSURL *url=[NSURL URLWithString:ApplePayWithSandBoxUrl];
    NSMutableURLRequest *requestM=[NSMutableURLRequest requestWithURL:url];
    requestM.HTTPBody=bodyData;
    requestM.HTTPMethod=@"POST";
    NSURLSessionDataTask *task= [[NSURLSession sharedSession] dataTaskWithRequest:requestM completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {

        if (error) {
            NSLog(@"验证购买过程中发生错误，错误信息：%@",error.localizedDescription);
            return;
        }

        NSDictionary *dic=[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
        NSLog(@"%@",dic);
        if([dic[@"status"] intValue]==0){
            NSLog(@"购买成功！");
        }else{
            NSLog(@"购买失败，未通过验证！");
        }
    }];
    [task resume];
}

//完成购买
- (void)completeTransaction:(SKPaymentTransaction *)transaction {

    [ZLToast dismiss];
    if ([self.delegate respondsToSelector:@selector(zlApplePaySuccessWithProductId:completeTransaction:)]) {
        [self.delegate zlApplePaySuccessWithProductId:self.currentProductId completeTransaction:transaction];
    } else {
        [self finishTransaction:transaction];
    }
}

//购买失败
- (void)failedTransaction:(SKPaymentTransaction *)transaction {

    [ZLToast dismiss];
    if(transaction.error.code != SKErrorPaymentCancelled) {
        NSString * msg = [NSString stringWithFormat:@"购买失败 :%@",transaction.error.localizedDescription];
        [ZLToast showHint:msg];
    } else {
        NSString * msg = [NSString stringWithFormat:@"用户取消交易"];
        [ZLToast showHint:msg];
    }
    [self finishTransaction:transaction];
}

// 恢复已经购买的产品
- (void)restoreTransaction:(SKPaymentTransaction *)transaction {

    [ZLToast dismiss];
    [self finishTransaction:transaction];
}

- (void)otherTransaction:(SKPaymentTransaction *)transaction {

    [ZLToast dismiss];
    [ZLToast showHint:@"支付挂起，请联系官方客服!"];
    [self finishTransaction:transaction];
}




#pragma mark - SKPaymentTransactionObserver (观察者监听购买状态的变化)
- (void)paymentQueue:(SKPaymentQueue *)queue
 updatedTransactions:(NSArray<SKPaymentTransaction *> *)transactions {
    for (SKPaymentTransaction *tran in transactions) {
        if (SKPaymentTransactionStatePurchasing == tran.transactionState) {

            [ZLToast showWithStatus:@"正在进行内购中,请不要离开."];
        } else if (SKPaymentTransactionStatePurchased == tran.transactionState) {

            [self completeTransaction:tran];
        } else if (SKPaymentTransactionStateRestored == tran.transactionState) {

            [self restoreTransaction:tran];
        } else if (SKPaymentTransactionStateFailed == tran.transactionState) {

            [self failedTransaction:tran];
        } else {

            [self otherTransaction:tran];
        }
    }
}


#pragma mark - SKProductsRequestDelegate (请求的代理)

// Sent immediately before -requestDidFinish:
- (void)productsRequest:(SKProductsRequest *)request
     didReceiveResponse:(SKProductsResponse *)response {
    //接收商品信息
    NSArray *product = response.products;
    if ([product count] == 0) {
        return;
    }
    // SKProduct对象包含了在App Store上注册的商品的本地化信息。
    SKProduct *currentProduct = nil;
    for (SKProduct *pro in product) {
        if ([pro.productIdentifier isEqualToString:self.currentProductId]) {
            currentProduct = pro;
        }
    }
    if (!currentProduct) {
        return;
    }
    //创建一个支付对象，并放到队列中
    SKMutablePayment * payment = [SKMutablePayment paymentWithProduct:currentProduct];
//    //设置购买的数量
//    payment.quantity = 1;
    [[SKPaymentQueue defaultQueue] addPayment:payment];
}

- (void)request:(SKRequest *)request didFailWithError:(NSError *)error {

    NSString * errorMsg = [NSString stringWithFormat:@"支付请求错误:%@",error.localizedDescription];
    [ZLToast showHint:errorMsg];
    [ZLToast dismiss];
}

- (void)requestDidFinish:(SKRequest *)request {
    NSLog(@"支付请求成功=>开始调取ApplePay");
}


#pragma mark - public
- (void)startPayWithProductId:(NSString *)productId
                     delegate:(id <ZLApplePayDelegate>)delegate {

    //判断是否可进行支付
    if ([SKPaymentQueue canMakePayments]) {

        if (productId.length == 0) {
            [ZLToast showHint:@"传入的productId 是空的"];
            return;
        }
        self.currentProductId = productId;
        self.delegate = delegate;
        SKProductsRequest *request = [[SKProductsRequest alloc] initWithProductIdentifiers:[NSSet setWithObjects:productId, nil]];
        request.delegate = self;
        [request start];
        [ZLToast showWithStatus:@"正在发起支付"];
    } else {
        [ZLToast showHint:@"不允许程序内付费"];
    }
}

- (void)finishTransaction:(SKPaymentTransaction *)transaction {
    [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
}
@end