How to set alerts in UNNotificationCenter some days before?

Question

How I can make local notification be triggered before some days? For example, I create local notifications from dateComponents:

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

I get days from:

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

But how I can set them triggered before one day at specifiс time?

I recommend to read [this](https://stackoverflow.com/questions/45061324/repeating-local-notifications-for-specific-days-of-week-swift-3-ios-10) — Vadim Nikolaev, Dec 17 '19 at 13:46
Thank you, but I haven't found a solution there. This thread only about triggering for specific days of week. — ucelme, Dec 17 '19 at 14:03
your question is not clear. Please specify which cases are understood as "before some days?" What kind of days? — Vadim Nikolaev, Dec 17 '19 at 14:29

score 2 · Accepted Answer · answered Dec 17 '19 at 14:39

2

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)
}

answered Dec 17 '19 at 14:39

Vadim Nikolaev

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Thank you for solution! – ucelme Dec 17 '19 at 14:46

How to set alerts in UNNotificationCenter some days before?

1 Answers1