ios - 如何在 Core Data 中添加和更新多对多关系？

Question

我设置了两个具有多对多关系的核心数据模型。

class BuddyCD: NSManagedObject {
    @NSManaged var memberOfBunches: NSSet
}

class BunchCD: NSManagedObject {
    @NSManaged var bunchMembers: NSSet
}

旁注:CD 在此表示核心数据我在创建BunchCD时，想添加很多好友作为成员。

我在 Bunch 类中有这个方法:

class func createInManagedObjectContext (moc: NSManagedObjectContext, members: [BuddyCD]?) -> BunchCD {

    let newBunch = NSEntityDescription.insertNewObjectForEntityForName(CoreDataConst.bunchModel, inManagedObjectContext: moc) as! BunchCD

    if let membersNonOptional = members {
        // Add members to this bunch

        for member in membersNonOptional {
            member.addToBunch(newBunch)
        }
    }
    return newBunch
}

我在 Buddy 类中有这个方法:

func addToBunch(bunch: BunchCD) {
    var bunches = self.mutableSetValueForKey("memberOfBunches")
    bunches.addObject(bunch)
}

我收到此错误:

2015-07-19 01:00:38.587 MyApp[34979:1885727] -[__NSSetIobjectAtIndex:]: unrecognized selector sent to instance 0x7fb7d3ecde30 2015-07-19 01:00:38.603 LunchBunch[34979:1885727] ***Terminating app due to uncaught exception'NSInvalidArgumentException', reason: '-[__NSSetI objectAtIndex:]: unrecognized selector sent to instance 0x7fb7d3ecde30'

将成员添加到核心数据中的多对多关系的最佳实践是什么？

Answer 1

你的代码看起来没问题。错误必定源自其他地方。也许您可以通过单步执行代码来找出位置。