小编tiw*_*tiw的帖子

Swift 4.1、Xcode 9.3、可可应用程序

如何从 string.index 获取 Int 以便与其他属性编号一起使用？

@IBOutlet weak var inputFromTextField: NSTextField!
@IBAction func button(_ sender: NSButton) {
    let temporaryHolder = inputFromTextField.stringValue.characters
    for input in temporaryHolder {
        let distance = temporaryHolder.index(of: input)
        print(input)
        print(distance + 100)
}

错误代码：

二元运算符“+”不能应用于“String._CharacterView.Index?”类型的操作数 （又名“可选< String.Index >”）和“Int”

我知道之前有人问过:iPhone In App Purchase - response.products仍然是空的？

但我也在尝试实施应用内购买和我的回复.产品是空的.我的情况:

我上传并拒绝了我的二进制文件一次

但后来我把状态恢复到等待再次上传.(这有关系吗？)

我所有的应用内购买产品的状态是"准备提交".

我的生产用户已退出.测试用户尚未登录.

-(void) requestProductData{
    SKProductsRequest *productRequest= [[SKProductsRequest alloc] 
                                 initWithProductIdentifiers:[NSSet setWithObjects:
                                                             @"com.mydomain.myapp.Pack1", 
                                                             @"com.mydomain.myapp.Pack2",
                                                             @"com.mydomain.myapp.Pack3",nil]];

productRequest.delegate = self;
[productRequest start];
}

-(void)productsRequest:(SKProductsRequest *)request 
    didReceiveResponse:(SKProductsResponse *)response{

NSArray *myProducts = response.products; 

NSLog(@"%d",[myProducts count]);//this prints 0
for(SKProduct * product in myProducts) {
    [products addObject:product];
}
[request autorelease]; 


}

    in my viewdidload:


if([SKPaymentQueue canMakePayments]) {
        NSLog(@"IN-APP:can make payments");
    }
    else {
        NSLog(@"IN-APP:can't make payments");
    }

    /*load transaction history to see if the user already bought some …