卡住：Swift iOS中的模拟时钟

Question

I'm new to swift (and coding in general), and I've been working on an analog watch project. I've gotten to a place where I'm stuck. None of the println() commands are putting anything out to the console unless they arrive before the function "func setTime(){...} ". Not sure what's happening there. And I can't seem to get the hands to rotate with the math I found here . I'm trying to convert it from obj-c to swift. (I know the bottom section is very wrong at the moment) I keep messing with it (the bottom section) but I don't get any rotation.

Any help would be appreciated. I feel like I'm close.

    var theTimer:NSTimer!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    println(viewDidLoad)

    func setTime(){

        println("set time")

        self.theTimer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "set time", userInfo: nil, repeats: false)

        let date = NSDate()
        let outputFormatter = NSDateFormatter()
        outputFormatter.dateFormat = "hh:mm:ss"
        let newDateString:NSString = outputFormatter.stringFromDate(date)
        println(newDateString)

        let calendar = NSCalendar.currentCalendar()
        let components = calendar.components(.CalendarUnitHour | .CalendarUnitMinute | .CalendarUnitSecond, fromDate: date)
        var hour = components.hour
        var minute = components.minute
        var second = components.second

        println(hour)
        println(minute)
        println(second)

        **var secAngle = (6 * second)
        var minAngle = (6 * minute)
        var hourAngle = (30 * hour + minute / 2)

        self.secsImage.transform = CGAffineTransformMakeRotation( CGFloat(secAngle) )
        self.minsImage.transform = CGAffineTransformMakeRotation( CGFloat(Double(minAngle)) )
        self.hoursImage.transform = CGAffineTransformMakeRotation( CGFloat(Double(hourAngle)) )**

        println(secAngle)
        println(minAngle)
        println(hourAngle)
}
}

Answer 1

You have declared your setTime function inside your viewDidLoad function, and you have never called it. Also, your the selector for your NSTimer is not correct - it needs to be the name of the function and it needs to be a Selector , not just a string.

You should move the setTime function declaration out of viewDidLoad and I would suggest setting it up in viewWillAppear -

var theTimer:NSTimer?

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    println(viewDidLoad)
}

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    self.setTime()

    self.theTimer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("setTime"), userInfo: nil, repeats: true)

}

func setTime(){

    println("set time")
    let date = NSDate()
    let outputFormatter = NSDateFormatter()
    outputFormatter.dateFormat = "hh:mm:ss"
    let newDateString:NSString = outputFormatter.stringFromDate(date)
    println(newDateString)

    let calendar = NSCalendar.currentCalendar()
    let components = calendar.components(.CalendarUnitHour | .CalendarUnitMinute | .CalendarUnitSecond, fromDate: date)
    var hour = components.hour
    var minute = components.minute
    var second = components.second

    println(hour)
    println(minute)
    println(second)

    var secAngle = (6 * second)
    var minAngle = (6 * minute)
    var hourAngle = (30 * hour + minute / 2)

    self.secsImage.transform = CGAffineTransformMakeRotation( CGFloat(secAngle) )
    self.minsImage.transform = CGAffineTransformMakeRotation( CGFloat(Double(minAngle)) )
    self.hoursImage.transform = CGAffineTransformMakeRotation( CGFloat(Double(hourAngle)) )**

    println(secAngle)
    println(minAngle)
    println(hourAngle)
}

If you are new to programming, you may want to consider running through some basic coding tutorials on the web.