如何调用返回的函数（发送方：UIDatePicker）-Swift

Question

I have a function named handler . I don't know how to call it in viewDidLoad . Here is the whole function:

@IBOutlet weak var theDatePicker: UIDatePicker!

    func handler(sender: UIDatePicker) {
        var timeFormatter = NSDateFormatter()
        timeFormatter.timeStyle = NSDateFormatterStyle.ShortStyle

        var strDate = timeFormatter.stringFromDate(theDatePicker.date)
        let alert = UIAlertController(title: "WAKE UP", message:nil, preferredStyle: UIAlertControllerStyle.Alert);


        alert.message = "Time to wake up " + strDate;


        let dismissHandler = {
            (action: UIAlertAction!) in
            self.dismissViewControllerAnimated(true, completion: { () -> Void in
            })
        }

        alert.addAction(UIAlertAction(title: "I'm Up!", style: .Default, handler: dismissHandler))
        presentViewController(alert, animated: true) { () -> Void in

        }

    }

Here is how I called it in viewDidLoad :

handler(sender:UIDatePicker)

It shows errors when I put that in here are the errors:

Expected member name or constructor call after type name Cannot convert the expression's type (sender: UIDatePicker.Type)' to type '(UIDatePicker) -> ()

Thank you for your time and patience, if you have any questions or need any clarification please comment.

Answer 1

Your function as you've defined it would be called with an instance of UIDatePicker as a parameter, not with the class. For example:

handler(sender:theDatePicker)

Also, your question title indicates that you might misunderstand function definitions. Your sender:UIDatePicker is a parameter of your function, not a return value.

Answer 2

I think you meant to call:

handler(sender: theDatePicker)

This passes it your UIDatePicker object rather than the UIDatePicker class.

Answer 3

When calling the function, you don't need to specify the type. So, just handler(sender) will do.