我怎么知道特定日期是一个月还是一个星期到父母日期？

Question

Lets say i have a program that reminds users of their appointments , from the current date until the date of the appointment, i want to find out if a particular date is a week to the appointment or a month to the appointment .

var startDate = startDate
let calendar = Calendar.current

let fmt = DateFormatter()
fmt.dateFormat = "yyyy-MM-dd"

while startDate <= endDate {

    var  newDate = calendar.date(byAdding: .day, value: 1, to: startDate)!


    if newDate is a month to endDate {

        //schedule reminder
    }

    if newDate is a week to endDate{

        //schedule reminder
    }

how can i check if the current date is a week/month to the appointment ?

Answer 1

You don't need to use any date comparison, you can simply generate the notification dates using Calendar.date(byAdding:value:to:) and just passing the correct components. To set the date 1 week/month before endDate , pass -1 to value.

let oneWeekBeforeAppointment = Calendar.current.date(byAdding: .weekOfYear, value: -1, to: endDate)!
let oneMonthBeforeAppointment = Calendar.current.date(byAdding: .month, value: -1, to: endDate)!

Answer 2

Try this to calculate the duration in days

func DateFormat() -> DateFormatter {
  let dateFormatter = DateFormatter()
  dateFormatter.dateFormat = "dd/MM/yyyy"
  dateFormatter.timeZone = TimeZone(abbreviation: "GMT")
  return dateFormatter
}

var appointementDate: Date?
var today = Date()

appointementDate = DateFormat().date(from: "22/02/2020")
today = DateFormat().date(from: DateFormat().string(from: today))!

let timeInterval = Int(exactly: (today.timeIntervalSince(appointementDate!))) ?? 0
print("\(timeInterval/86400) days left")