如何按 nextTriggerDate 对 UNNotificationRequests 数组进行排序答案

【问题标题】：How to sort an array of UNNotificationRequests by nextTriggerDate如何按 nextTriggerDate 对 UNNotificationRequests 数组进行排序
【发布时间】：2018-10-21 01:57:33
【问题描述】：

我有一个UNNotificationRequest 数组。我想按nextTriggerDate对它们进行排序。

据我了解，我会使用 array.sorted(by:predicate) 对数组进行排序

let sortedNotifications = notificationRequests.sorted(by: { $0.trigger.nextTriggerDate?.compare($1.trigger.nextTriggerDate!) == .orderedAscending })

但是，问题是 .trigger 没有 nextTriggerDate 属性。

为了获得nextTriggerDate，我必须提取触发器并将其转换为UNCalendarNotificationTrigger。据我所知，这不能在谓词中完成。

有什么想法吗？

【问题讨论】：

标签： ios sorting nspredicate unnotificationrequest unnotificationtrigger

【解决方案1】：

您可以使用 UNNotificationRequest 和 nextTriggerDate (UNNotificationRequest,nextTriggerDate) 创建Tuple

// get request with date Tuple -->  example : (value0,value1)

let requestWithDateTuple =  notificationRequests.map({ (req) -> (UNNotificationRequest,Date?)? in
                    guard let trigger = req.trigger as? UNCalendarNotificationTrigger else {
                        return nil
                    }
                    return (req,trigger.nextTriggerDate())
                }).compactMap({$0})

                // you will get Tuple (request,Date) ,sort them by date  
               let sortedTuple = requestWithDateTuple.sorted(by: { $0.1?.compare($1.1!) == .orderedAscending })

// sorted request only 
let requestSorted =  sortedTuple.map({$0.0})

【讨论】：