Question

我试图比较两个日期之间的天数 - （当前日期和用户选择日期） - 并将差异存储在变量var daysleft = 0

中

但是，我使用的代码daysleft总是显示1天太少。基本术语：当前日期和明天日期结果具有相同的值（0）

比较代码;

var daysleft = 0

let DayDifference = userCalendar.components(
        dayCalendarUnit,
        fromDate: Date,
        toDate: dateView.date,
        options: [])

    daysleft = DayDifference.day

额外代码;

如果您需要查看用户选择的日期代码，可以使用以下代码;

datePickerView.datePickerMode = UIDatePickerMode.Date
    sender.inputView = datePickerView
    datePickerView.addTarget(self, action: Selector("datePickerValueChanged:"), forControlEvents: UIControlEvents.ValueChanged)


func datePickerValueChanged(sender:UIDatePicker) {
    let dateFormatter = NSDateFormatter()
    dateFormatter.dateStyle = NSDateFormatterStyle.MediumStyle
    dateFormatter.timeStyle = NSDateFormatterStyle.NoStyle
    DateTextField.text = dateFormatter.stringFromDate(sender.date)
    dateMakerFormatter.calendar = userCalendar
    dateMakerFormatter.dateFormat = "yyyy/MM/dd"
}

修改

以下是我使用的日期;

当前日期为;

let Date = NSDate()

用户选择的日期;

var datePickerView:UIDatePicker = UIDatePicker()
let dayCalendarUnit: NSCalendarUnit = [.Day]
let dateFormatter = NSDateFormatter()

datePickerView.datePickerMode = UIDatePickerMode.Date
    sender.inputView = datePickerView
    datePickerView.addTarget(self, action:   Selector("datePickerValueChanged:"), forControlEvents: UIControlEvents.ValueChanged)

func datePickerValueChanged(sender:UIDatePicker) {
let dateFormatter = NSDateFormatter()
dateFormatter.dateStyle = NSDateFormatterStyle.MediumStyle
dateFormatter.timeStyle = NSDateFormatterStyle.NoStyle
DateTextField.text = dateFormatter.stringFromDate(sender.date)
dateMakerFormatter.calendar = userCalendar
dateMakerFormatter.dateFormat = "yyyy/MM/dd"

}

比较;

dayCalendarUnit,
    fromDate: Date,
    toDate: datePickerView.date,
    options: [])

daysleft = DayDifference.day

Answer 1

问题是这两个日期之间没有一整天的差异（24 +小时）。

您需要获得每个component:fromDate:的日期并减去天数。您可能需要处理数月和数年。

或

在使用components:fromDate:toDate:options:计算日差之前，将时间设置为0。

Answer 2

由于您的today有时间，因此与用户的选择日期相差不到24小时。

您需要关闭时间组件：

let userCalendar = NSCalendar.currentCalendar()

// Only get the Year, Month, Day of `now`
let components = userCalendar.components([.Year, .Month, .Day], fromDate: NSDate())
let today = userCalendar.dateFromComponents(components)!

// Assume the user picked Mar 28, 2016
let userPickedDate = userCalendar.dateWithEra(1, year: 2016, month: 3, day: 28, hour: 0, minute: 0, second: 0, nanosecond: 0)!

let dayDifference = userCalendar.components([.Day], fromDate: today, toDate: userPickedDate, options: [])

print(today)
print(userPickedDate)
print(dayDifference.day)

NSDate比较一天

2 个答案: