Question

小时。我有一个名为Agendadate的实体和一个名为AgendaEvent的实体。 AgendaEvent与AgendaDate（agendaDates）存在多种关系。

在我的AgendaDate中，我有一个对象日期（日期类型）。

我正在使用这样的谓词：

fetchRequest.predicate = NSPredicate(format: "ANY agendaDates.dates == %@", date as CVarArg)

我试图将日期格式设置为：

＆＃34; dd MM yyyy＆＃34;而不是＆＃34; yyyy MM dd hh：mm：ss＆＃34;

我需要在谓词中比较两个日期但没有时间吗？有可能吗？

UPDATE ----- 根据您的建议，我的功能已更新：

func agendaEventsWithDate(date: Date) -> NSFetchRequest<AgendaEvent>
{
    // create a fetch request that will retrieve all the AgendaEvents.
    let fetchRequest = NSFetchRequest<AgendaEvent>(entityName: "AgendaEvent")

    // set the predicate to only keep AgendaEvents where the related AgendaDate's date matches the passed in date.
    let cal = Calendar.current
    let startOfDay = cal.startOfDay(for: eventDate)
    let endOfDay = cal.date(byAdding: .day, value: 1, to: startOfDay)!
    print(startOfDay)
    print(endOfDay)
    // fetchRequest.predicate = NSPredicate(format: "ANY agendaDates.agendaDates == %@", date as CVarArg)
     fetchRequest.predicate = NSPredicate(format: "SUBQUERY(agendaDates, $a, $a.dates >= %@ AND $a.dates < %@).@count > 0",
                                startOfDay as NSDate, endOfDay as NSDate)

    return fetchRequest
}

以及这里应该配置单元格的函数，并且只接受与所选日期具有相同日期的事件：

func configuringCell(cell: CalendarAgendaCell, indexPath: IndexPath) {
    for dates in calendar.selectedDates {
        for dateOfEvent in myEventDate {
            formatter.dateFormat = "dd MM yyyy"
            let dateToCompare = formatter.string(from: dates)
            formatter.dateFormat = "dd-MM-yyyy"
            let comparingDate = formatter.date(from: dateToCompare)!
            if dateOfEvent == dateToCompare {
                myTempEvents = try! context.fetch(agendaEventsWithDate(date: comparingDate))
                let myEvent = myTempEvents[indexPath.row]
                cell.configureCell(agendaEvent: myEvent)

            } else {
               // the array is empty

            }
        }
    }
}

Answer 1

不要为此目的使用自定义字符串格式。你想要获取与具有日期的Agendadate对象相关的所有条目在同一天的同一天。

因此，您首先计算当天的开始和结束时间：

let date = Date()

let cal = Calendar.current
let startOfDay = cal.startOfDay(for: date)
let endOfDay = cal.date(byAdding: .day, value: 1, to: startOfDay)!

然后使用此SUBQUERY：

let predicate = NSPredicate(format: "SUBQUERY(agendaDates, $a, $a.dates >= %@ AND $a.dates < %@).@count > 0",
                            startOfDay as NSDate, endOfDay as NSDate)

它为所有人测试$a.dates >= startDate AND $a.dates < endDate 相关对象，如果至少有一个匹配则产生true 条件。

Swift coreData - 格式化日期并在谓词中使用它

1 个答案: