快速功能与args…传递到另一个功能与args

I have a simple problem. I tried search in many blogs about this question but all site return how function in swift work, but I need this case.

我有一个简单的问题。我尝试在很多博客上搜索这个问题，但是所有的网站都返回如何快速工作，但是我需要这个案例。

My custom function is:

我的自定义函数是:

func getLocalizeWithParams(args:CVarArgType...)->String {
     return NSString.localizedStringWithFormat(self, args); //error: Expected expression in list of expressions
}

How I do to pass my args to other system function with args?

如何将args传递给其他系统函数?

Thanks advance.

谢谢你提前。

2 个解决方案

#1

Similar as in (Objective-)C, you cannot pass a variable argument list directly to another function. You have to create a CVaListPointer (the Swift equivalent of va_list in C) and call a function which takes a CVaListPointer parameter.

类似于(Objective-)C，不能将变量参数列表直接传递给另一个函数。您必须创建一个CVaListPointer(在C中与va_list等价)，并调用一个接受CVaListPointer参数的函数。

So this could be what you are looking for:

这可能就是你要找的

extension String {
    func getLocalizeWithParams(args : CVarArgType...) -> String {
        return withVaList(args) {
            NSString(format: self, locale: NSLocale.currentLocale(), arguments: $0)
        } as String
    }
}

withVaList() creates a CVaListPointer from the given argument list and calls the closure with this pointer as argument.

withVaList()从给定的参数列表中创建一个CVaListPointer，并使用该指针作为参数调用闭包。

Example (from the NSString documentation):

示例(来自NSString文档):

let msg = "%@:  %f\n".getLocalizeWithParams("Cost", 1234.56)
print(msg)

Output for US locale:

输出为我们地区:

Cost:  1,234.560000

Output for German locale:

输出为德国语言环境:

Cost:  1.234,560000

Update: As of Swift 3/4 one can pass the arguments to

更新:Swift 3/4可以将参数传递给。

String(format: String, locale: Locale?, arguments: [CVarArg])

directly:

直接:

extension String {
    func getLocalizeWithParams(_ args : CVarArg...) -> String {
        return String(format: self, locale: .current, arguments: args)
    }
}

#2

I believe you're using NSString.localizedStringWithFormat(self, args) incorrectly. Otherwise nothing wrong with using args to call another function.

我相信你用的是NSString。localizedStringWithFormat(自我,args)不正确。否则，使用args调用另一个函数没有问题。

If you look below, you need to specify the format as NSString as the first argument: NSString.localizedStringWithFormat(format: NSString, args: CVarArgType...)

如果您看下面，您需要将格式指定为NSString作为第一个参数:NSString。localizedStringWithFormat(格式:NSString,arg游戏:CVarArgType…)

This SO question explains how to use it in Swift: iOS Swift and localizedStringWithFormat

这个问题解释了如何在Swift中使用它:iOS Swift和localizedStringWithFormat。

#1