ios - 如何在几天前在 UNNotificationCenter 中设置警报？

Question

如何在几天前触发本地通知？例如，我从 dateComponents 创建本地通知:

    var dateComponents = Calendar.current.dateComponents([.month, .day], from: birthDate)
    dateComponents.hour = 10
    dateComponents.minute = 30
    let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)

我的天数来自:

var dateComponents = Calendar.current.dateComponents([.month, .day], from: birthDate).

但我如何才能将它们设置为在某一天之前的特定时间触发？

Answer 1

if let oneDayAgo = Calendar.current.date(byAdding: .day, value: -1, to: birthDate) {
    var dateComponents = Calendar.current.dateComponents([.month, .day], from: oneDayAgo)
    dateComponents.hour = 10
    dateComponents.minute = 30
    let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)
}