Xcode "Expected Delcaration","Expression not allowed at the top level"错误

Question

当我收到“Expected Declaration”错误并且“Instance member”something”不能用于类型“viewcontroller”时，我试图在 viewcontroller.swift 文件中实现一个 NSDatecomponent

所以，我决定制作一个新的 .swift 文件，然后在那里实现 NSDatecomponents。但是后来我得到了“顶层不允许使用表达式”错误。

根据我在谷歌上的发现，我知道我应该在一个函数中实现它，但我不知道我应该把它包装成什么样的函数。我也想知道为什么我在 viewcontroller.swift 文件中得到错误以供将来引用。提前谢谢你，如果我的问题重复，我很抱歉。

这是原始代码

let weekBMondayComponents:NSDateComponents = NSDateComponents()
weekBMondayComponents.year = 2016
weekBMondayComponents.month = 01
weekBMondayComponents.day = 11
weekBMondayComponents.hour = 08
weekBMondayComponents.minute = 39
weekBMondayComponents.timeZone = NSTimeZone.systemTimeZone()
let weekBMonday = userCalendar.dateFromComponents(weekBMondayComponents)!

Answer 1

您需要将 weekBMondayComponents 声明为子类的属性或变量，并可能在 viewDidLoad 通知处理程序中对其进行初始化。

class ViewController: UIViewController {
    var weekBMondayComponents:NSDateComponents = NSDateComponents()

func setUpADay() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    weekBMondayComponents.year = 2016
    weekBMondayComponents.month = 01
    weekBMondayComponents.day = 11
    weekBMondayComponents.hour = 08
    weekBMondayComponents.minute = 39
    weekBMondayComponents.timeZone = NSTimeZone.systemTimeZone()
}