倒数迅速返回错误的天数

Question

我正在尝试以快速获取天，小时，分钟和秒的形式实现到特定日期的倒计时，但是由于某种原因，我的实现返回了错误的天数，直到发生事件，但返回的是正确的时数，分钟和秒。我不确定这里出了什么问题：

let date = Date()

let calendar = Calendar.current

let components = calendar.dateComponents([.second, .minute, .hour, .day], from: date as Date)

let currentDate = calendar.date(from: components)

let userCalendar = Calendar.current

let openingNight = NSDateComponents()
openingNight.year = 2020
openingNight.month = 9
openingNight.day = 10
openingNight.hour = 20
openingNight.minute = 30
openingNight.second = 0

let opener = userCalendar.date(from: openingNight as DateComponents)

let difference = calendar.dateComponents([.second, .minute, .hour, .day], from: currentDate!, to: opener!)

let daysLeft = difference.day
let hoursLeft = difference.hour
let minutesLeft = difference.minute
let secondsLeft = difference.second

daysLabel.text = "\(daysLeft!)"
hourLabel.text = "\(hoursLeft!)"
minuteLabel.text = "\(minutesLeft!)"
secondLabel.text = "\(secondsLeft!)"

返回737661天4小时2分28秒

Answer 1

currentDate的dataComponents中缺少月份和年份。这将给出正确的差异（此处仍然是5月19日，所以距离9月10日还有114天）。

let date = Date()
let calendar = Calendar.current
let components = calendar.dateComponents([.second, .minute, .hour, .day, .month, .year], from: date as Date)
let currentDate = calendar.date(from: components)
let userCalendar = Calendar.current

let openingNight = NSDateComponents()
openingNight.year = 2020
openingNight.month = 9
openingNight.day = 10
openingNight.hour = 20
openingNight.minute = 30
openingNight.second = 0

let opener = userCalendar.date(from: openingNight as DateComponents)

let difference = calendar.dateComponents([.second, .minute, .hour, .day], from: currentDate!, to: opener!)

let daysLeft = difference.day
let hoursLeft = difference.hour
let minutesLeft = difference.minute
let secondsLeft = difference.second

print(difference) // day: 114 hour: 2 minute: 34 second: 6 isLeapMonth: false