Question

我从核心数据中获取。我有一个属性是一个用时间属性保存的bool。我需要返回一个bool为真的日期数组。我无法让它工作，我得到一个空日期数组或崩溃。

func datesWithCompleteHBI() -> [Date] {

  let managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
  fetchRequest.resultType = .dictionaryResultType
  fetchRequest.propertiesToFetch = ["savedTime", "harveyBradshawIndexComplete"]

  let timeSort = NSSortDescriptor(key: "savedTime", ascending: false)
  let hbiSort = NSSortDescriptor(key: "harveyBradshawIndexComplete", ascending: false)
  fetchRequest.sortDescriptors = [timeSort, hbiSort]

  let messageKey = true
  fetchRequest.predicate = NSPredicate(format: "harveyBradshawIndexSaveLevel = %@", messageKey as CVarArg)

  var dates = [Date]()
  do {

      let results = try managedObjectContext.fetch(fetchRequest) as! [[String:Date]]

      dates = results.flatMap { $0["savedTime"]}

     } catch let error as NSError {
       print("Could not fetch \(error), \(error.userInfo)")

    }

 print("hbi date array \(dates)")
 return dates
 }
}

Answer 1

如果您要返回Date和Bool，则返回值不能为[[String:Date]]

let results = try managedObjectContext.fetch(fetchRequest) as! [[String:Any]]

不是过滤代码中的项，而是将过滤条件添加到谓词

fetchRequest.predicate = NSPredicate(format: "harveyBradshawIndexSaveLevel = %@ AND savedTime == TRUE", messageKey as CVarArg)

现在results包含已过滤的项目。

带有多个sortDescriptors和Bool过滤器的Swift fetchRequest

1 个答案: