UserNotifications cancel, swift3

问题:

I'm working on app where user can set time for everyday local notification, then I have an option to enable or disable these notifications. My question how I can disable/cancel already setted notification?

Here in one of this IFs I need to cancel notif

override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

    if (indexPath as NSIndexPath).row == 1 && switchiBtn.isOn == false {

        return 0.0
    }
    if (indexPath as NSIndexPath).row == 2 {
        if switchiBtn.isOn == false || dpVisible == true {
            return 0.0
        }
        return 216.0
    }

    if (indexPath as NSIndexPath).row == 3 {
        if switchiBtn.isOn == false || dpVisible == true {
            return 0.0
        }
        return 44
    }
    return 50.0
}

Here are functions for schedule and button where I'm setting notif.

func scheduleNotif(date: DateComponents, completion: @escaping (_ Success: Bool) -> ()) {

    let notif = UNMutableNotificationContent()

    notif.title = "Your quote for today is ready."
    notif.body = "Click here to open an app."



    let dateTrigger = UNCalendarNotificationTrigger(dateMatching: date, repeats: true)
    let request = UNNotificationRequest(identifier: "myNotif", content: notif, trigger: dateTrigger)

    UNUserNotificationCenter.current().add(request, withCompletionHandler: { error in

        if error != nil {
            print(error)
            completion(false)
        } else {
            completion(true)
        }
    })
}


@IBAction func setACTION(_ sender: AnyObject) {

    let hour = datePicker.calendar.component(.hour, from: datePicker.date)
    let minute = datePicker.calendar.component(.minute, from: datePicker.date)

    var dateComponents = DateComponents()
    dateComponents.hour = hour
    dateComponents.minute = minute
    print(dateComponents)

    scheduleNotif(date: dateComponents, completion: { success in
        if success {
            print("SUCCESS")

        } else {
            print("ERROR")
        }
    })

Thanks.

回答1:

For cancelling all pending notifications, you can use this:

UNUserNotificationCenter.current().removeAllPendingNotificationRequests()

For cancelling specific notifications,

UNUserNotificationCenter.current().getPendingNotificationRequests { (notificationRequests) in
   var identifiers: [String] = []
   for notification:UNNotificationRequest in notificationRequests {
       if notification.identifier == "identifierCancel" {
          identifiers.append(notification.identifier)
       }
   }
   UNUserNotificationCenter.current().removePendingNotificationRequests(withIdentifiers: identifiers)
}

回答2:

The way same UNNotification is identify are base on the identifier passed when you create the UNNotificationRequest.

In your example above,

let request = UNNotificationRequest(identifier: "myNotif", content: notif, trigger: dateTrigger)

You have actually hardcoded the identifier to be "myNotif". This way, whenever you want to delete the already set notification you can do this:

UNUserNotificationCenter.current().removePendingNotificationRequests(withIdentifiers: "myNotif")

However, do take note that when you hardcode the identifier, every time when you add a request to UNUserNotificationCenter the notification is actually being replaced.

Example, if you scheduled a "myNotif" request set on 1 minute later but you call another function to schedule a "myNotif" at 1 hour later it will be replaced. Therefore only the latest "myNotif" at one hour later will be in the pendingNotificationRequest.

回答3:

As mentioned here you can cancel all notifications with the following code:

UIApplication.sharedApplication().cancelAllLocalNotifications()