Question

我正在尝试在swift中编写以下Objective-C代码：

NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *now = [NSDate date];
NSDate *startOfTheWeek;
NSTimeInterval interval;
[cal rangeOfUnit:NSWeekCalendarUnit 
       startDate:&startOfTheWeek 
        interval:&interval 
         forDate:now];

它会将本周开头写为startOfTheWeek，将持续时间写为interval。

在我写的操场上

let now:NSDate = NSDate()
var startDate:NSDate
var duration: NSTimeInterval // also tried "var duration: CMutablePointer<NSTimeInterval>"
let cal = NSCalendar.currentCalendar()
cal.rangeOfUnit(unit: NSCalendarUnit.WeekCalendarUnit, startDate: startDate, interval: duration, forDate: now)"

虽然代码完成告诉我签名是

cal.rangeOfUnit(<#unit: NSCalendarUnit#>, startDate: AutoreleasingUnsafePointer<NSDate?>, interval: <#CMutablePointer<NSTimeInterval>#>, forDate: <#NSDate?#>)

发生错误Extra argument 'interval' in call

我做错了什么？

我也试过

cal.rangeOfUnit(NSCalendarUnit.WeekCalendarUnit, startDate: startDate, interval: duration, forDate: now)

但这会产生错误

＆＃34;找不到＆range; rangeOfUnit＆＃39;接受提供的参数。＆＃34;

Answer 1

试试这个：

let now = NSDate()
var startDate: NSDate? = nil
var duration: NSTimeInterval = 0
let cal = NSCalendar.currentCalendar()

cal.rangeOfUnit(NSCalendarUnit.WeekCalendarUnit, startDate: &startDate,
    interval: &duration, forDate: now)

（默认情况下，第一个参数没有外部名称，因此不应命名。）

将参数传递给方法时出错“调用中的额外参数”

1 个答案: