我正在尝试开发一个包含简单秒表功能的应用程序.我正在使用
Xcode 6和
Swift语言.这是FirstViewController中的代码
@IBAction func Stopwatch (Sender:UIButton) {
var startTime = NSTimeInterval()
func updateTime(timer:NSTimer) {
//Find Current TIme
var currentTime = NSDate.timeIntervalSinceReferenceDate()
//Find the difference between current time and start time
var elapsedtime :NSTimeInterval = currentTime - startTime
//calculate the minutes in elapsed time.
let minutes = UInt(elapsedtime / 60.0)
elapsedtime -= (NSTimeInterval(minutes) * 60)
//calculate the seconds in elapsed time.
let seconds = UInt(elapsedtime)
elapsedtime -= NSTimeInterval(seconds)
//find out the fraction of milliseconds to be displayed.
let hours = UInt(elapsedtime * 100)
let strMinutes = minutes > 9 ? String(minutes):String(minutes)
let strSeconds = seconds > 9 ? String(seconds):String(seconds)
let strHours = hours > 9 ? String(hours):String(hours)
//assign text to Label
elapsedtimeLabel.text = "You have slept for \(strHours)"
}
//Timer
var timer = NSTimer.scheduledTimerWithTimeInterval(0.5,target: self,selector: Selector("updateTime:"),userInfo: nil,repeats: true)
startTime = NSDate.timeIntervalSinceReferenceDate()
}
}
每次我运行应用程序(在iOS模拟器中)时,按下按钮时应用程序崩溃(执行秒表功能).错误总是会读取
2014-11-23 11:44:53.617 Sleep[9630:644637] -[Sleep.FirstViewController updateTime:]: unrecognized selector sent to instance 0x7ff6d9676e80 2014-11-23 11:44:53.622 Sleep[9630:644637] *** Terminating app due to uncaught exception 'NSinvalidargumentexception',reason: '-[Sleep.FirstViewController updateTime:]: unrecognized selector sent to instance 0x7ff6d9676e80' *** First throw call stack:
我不知道为什么会这样,我对iOS编程很新,所以请帮忙！
解决方法
让updateTime成为一个类方法.
如果它是在一个纯粹的Swift类中,你需要在@objc前面说明该方法的声明,如：
如果它是在一个纯粹的Swift类中,你需要在@objc前面说明该方法的声明,如：
class A {
@objc func updateTime(timer:NSTimer) {
}
}