如何使用 UNNotificationRequest 将本地通知设置为在每个月的最后一天触发？

Question

我试图将本地通知设置为在每个月的最后一天触发，无论是 28 日、29 日、30 日还是 31 日。

使用之前的框架UILocalNotification，我可以指定fireDate 和repeatInterval，它可以工作。但是现在我将框架更新为UNNotofication，我尝试使用UNCalendarNotificationTrigger 并将DateComponents' 日期设置为0。然而并没有火。有什么我做错了吗？谢谢！

代码如下。 nextTriggerDate 为零。

var components = DateComponents()
components.hour = 8
components.minute = 0
components.day = 0

let trigger = UNCalendarNotificationTrigger(dateMatching: components, repeats: true)
print(trigger.nextTriggerDate())

Answer 1

您可以使用以下代码，显示通知后计算下一个最后一天的月份。

class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge])
    { (granted, error) in
        // Enable or disable features based on authorization
    }
    let current = UNUserNotificationCenter.current()
    current.delegate = self
    setNotificationRequest()
}


func setNotificationRequest(offset: Int = 0) {
    let content = UNMutableNotificationContent()
    content.title = "Alarm"
    content.body = "Alarm for End of Month"
    content.sound = UNNotificationSound.default
    
    var dateCompo = DateComponents()
    dateCompo.day = lastDay(offset: offset)
    let trigger = UNCalendarNotificationTrigger.init(dateMatching: dateCompo, repeats: true)
    let request = UNNotificationRequest(identifier: "alarm-id", content: content, trigger: trigger)
    UNUserNotificationCenter.current().removeAllPendingNotificationRequests()
    UNUserNotificationCenter.current().add(request)
}
func lastDay(offset: Int) -> Int {
    let cal = Calendar.current
    let m = cal.component(.month, from: Date()) + 1
    let y = cal.component(.year, from: Date())
    var comps = DateComponents(calendar: cal, year: y, month: m)
    comps.setValue(m + 1, for: .month)
    comps.setValue(0, for: .day)
    let date = cal.date(from: comps)!
    return cal.component(.day, from: date)
} }


extension ViewController: UNUserNotificationCenterDelegate {
func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    // offset is set to 1 as we want to get last of next month now.
    setNotificationRequest(offset: 1)
    completionHandler([.badge, .sound])
} }

我已经测试过了，对我来说工作正常。