ios - 在 Swift 中获取某一天的事件数

Question

在我的应用程序中，我想在应用程序启动时显示通知，说明当天的事件数。到目前为止，我的代码如下所示:

//after appending the arrays with data from api   
    DispatchQueue.main.async {
        print("Dates in array: \(self.datesArray)")

        if self.datesArray.contains(dateString){
            //check how many events on that day
            let newIndex = self.datesArray.index(of: dateString)

            print("newIndex: ", newIndex!)// position of current date
            print("Events today: ", self.datesArray)
            self.notificationPublisher.sendNotification(title: "Events", subtitle: "", body: "\(self.datesArray.count) today", delayInterval: nil )
        } else {
            self.notificationPublisher.sendNotification(title: "Events", subtitle: "", body: "No events today", delayInterval: nil)
        }
    }

我想过以某种方式找到一种方法来填充 datesArray 数组，这样我就可以显示当天的事件数，但我不确定该怎么做。我的处理方式是否正确？

编辑:我从这里使用了一种检查数组中重复元素的方法:How to count occurrences of an element in a Swift array?

所以现在我的代码看起来像这样:`DispatchQueue.main.async { print("数组中的日期:(self.datesArray)")

                if self.datesArray.contains(dateString){

                    self.datesArray.forEach{self.counts[$0, default: 0] += 1}
                    print("Counts: ", self.counts)

                    self.notificationPublisher.sendNotification(title: "Events", subtitle: "", body: "No events today", delayInterval: nil)

                }

            }`

Count 输出所有数组元素以及它们出现的次数。我如何使用该数据来显示特定日期有多少事件？

Answer 1

检查你的 self.datesArray 是否有一些值，

print(self.datesArray)

并计算今天的事件数为:

let todayEvent = self.datesArray.filter({ $0 == dateString })

总计:

let datesArray = ["2018-08-21", "2018-08-10", "2018-08-30", "2018-09-17", "2018-08-21", "2018-09-17"]

fileprivate lazy var dateFormatter: DateFormatter = {
    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    return formatter
}()

func postNotificationForTodaysEvent() {
    print("Dates in array: \(self.datesArray)")

    DispatchQueue.main.async {
        let dateString = self.dateFormatter.string(from: Date())
        let todayEvent = self.datesArray.filter({ $0 == dateString }) // It will fetched the event from same date
        print(todayEvent)
        if todayEvent.isEmpty {
            self.notificationPublisher.sendNotification(title: "Events", subtitle: "WeAsean", body: "No events today", delayInterval: nil)
        } else {
            self.notificationPublisher.sendNotification(title: "Events", subtitle: "WeAsean", body: "\(todayEvent.count) today", delayInterval: nil )
        }
    }
}

结果将是:

Dates in array: ["2018-08-21", "2018-08-10", "2018-08-30", "2018-09-17", "2018-08-21", "2018-09-17"]

today's events are:["2018-09-17", "2018-09-17"]