ios - 为什么 UIImage 不会改变？

Question

我查看了很多资源，但没有一个对我有用。我正在尝试根据星期几更改图像。我在 Playground 上测试了日历方法，它会返回正确的预期数字。但是，我对 Swift 和编程以及一般知识还很陌生，对于为什么 imageChange 方法不会改变一无所知。

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var schedule: UIImageView!



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

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    var monday = UIImage(named: "monday")
    var tuesday = UIImage(named: "tuesday")
    var wednesday = UIImage(named: "wednesday")
    var thursday = UIImage(named: "thurday")
    var friday = UIImage(named: "friday")
    var other = UIImage(named:"other")




    func calendar()->Int{
        let todayDate = NSDate()
        let myCalendar = NSCalendar(calendarIdentifier: NSGregorianCalendar)

        let myComponents = myCalendar?.components(.WeekdayCalendarUnit, fromDate: todayDate)
        let weekDay = myComponents?.weekday
        return weekDay!
    }
    func imageChange() {
        if calendar() == 2 {
            schedule.image = monday
        }

        else if calendar() == 3 {
            schedule.image = tuesday
        }

        else if calendar() == 4 {
            schedule.image = wednesday
        }

        else if calendar() == 5 {
            schedule.image = thursday
        }

        else if calendar() == 6 {
            schedule.image = friday
        }

        else if calendar() == 7 {
            schedule.image = other
        }

        else if calendar() == 1 {
            schedule.image = other
        }

        else {
            schedule.image = other
        }
    }    
}

Answer 1

你可以让你的函数更短更简单:

//Add all your images to an array(other two times for saturday and sunday)
//0 = saturday, 1 = sunday, 2 = monday etc
var imageArray = [other, other, monday, tuesday, wednesday, thursday, friday]

func imageChange() {
    //Call the function only one time. No need to call it each time you test
    var calendarDay = calendar()

    //You want to know which image you need from your array. -1 because an array starts at 0
    var imageIndex = calendarDay - 1

    schedule.image = imageArray[imageIndex]

}

要调用您的函数，您必须在函数内部进行。您不能仅从类体内运行函数。因此，例如在您的 viewDidLoad 方法中:

override func viewDidLoad() {
    super.viewDidLoad()
    imageChange()
}