NSSet and Core Data

Question

我试图在核心数据中保存两个对象列表。我有一个协议方法，它将我的标签添加为(Tag)并将它们放入标签数组中。我无法保存这些对象，因为我使用NSSet和扩展名(swift)为:

extension CurrentTransaction {
func addTagObject(value:Tag) {
    var items = self.mutableSetValueForKey("tagMembers");
    items.addObject(value)
 }
 func removeTagObject(value:Tag) {
    var items = self.mutableSetValueForKey("tagMembers");
    items.removeObject(value)
 }
}

从核心数据我试图保存的两个对象是:

class Pic: NSManagedObject {
@NSManaged var picName: String!
@NSManaged var picNumber: String!
@NSManaged var currentTransaction: CurrentTransaction
class func createInManagedObjectContext(moc: NSManagedObjectContext, name: String, number: String) -> Pic {
    let newPic = NSEntityDescription.insertNewObjectForEntityForName("Pic", inManagedObjectContext: moc) as! Pic
    newPic.picName = name
    newPic.picNumber = number
    return newPic
}
}

类标记:

class Tag: NSManagedObject {
@NSManaged var tagName: String!
@NSManaged var tagNumber: String!
@NSManaged var currentTransaction: CurrentTransaction
class func createInManagedObjectContext(moc: NSManagedObjectContext, name: String, number: String) -> Tag {
    let newTag = NSEntityDescription.insertNewObjectForEntityForName("Tag", inManagedObjectContext: moc) as! Tag
    newTag.tagName = name
    newTag.tagNumber = number
    return newTag
}

}

类currentTransaction:

class CurrentTransaction: NSManagedObject {
@NSManaged var destinationPIC: String
@NSManaged var sourcePIC: String
@NSManaged var nvdNumber: String
@NSManaged var numberOfAnimals: NSNumber
@NSManaged var requestType: String
@NSManaged var date: NSDate
@NSManaged var tagMembers: NSSet
@NSManaged var picMembers: NSSet?

class func createInManagedObjectContext(moc: NSManagedObjectContext, toPic: String, fromPic: String, nvd: String, numAnimals: NSNumber, request: String, date: NSDate, tags: NSSet, pics: NSSet) -> CurrentTransaction {
    let newTransaction = NSEntityDescription.insertNewObjectForEntityForName("CurrentTransaction", inManagedObjectContext: moc) as! CurrentTransaction
    newTransaction.destinationPIC = toPic
    newTransaction.sourcePIC = fromPic
    newTransaction.nvdNumber = nvd
    newTransaction.numberOfAnimals = numAnimals
    newTransaction.requestType = request
    newTransaction.tagMembers = tags
    newTransaction.picMembers = pics
    newTransaction.date = date
    return newTransaction
}
}

当我调用CurrentTransaction.addTagObject(tag: tag)时，我得到"不能用类型为'(tag)'的参数列表调用'addTagObject'

这是我的addTags协议方法:

func addTags(tag: Tag) {
    //println("IN ADD TAGS")
    //println(tag.tagNumber)
    self.tagList.append(tag)
    CurrentTransaction.addTagObject(tag) //Error on this line
}

Answer 1

原因:addTagObject()未定义为类函数，不能在类CurrentTransaction上调用。如果您打算将其用作类函数，请将其更改为:

class func addTagObject(value:Tag) {
    var items = self.mutableSetValueForKey("tagMembers");
    items.addObject(value)
}