ios - 由于 NSManagedObjectContextObjectsDidChangeNotification 导致的运行时错误

Question

我遇到了这个运行时错误，它在刷新数据或启动时(从服务中获取并保存在 coreData 中)发生了 50% 的时间。我已经查看了关于这个问题的几乎所有解决方案，但其中大部分都在 Obj-C 中，但我是 iOS 的新手并且使用 swift。我有大约 20 个表，所有表都使用相同的上下文。

下面是我的代码:

public class ServiceCalls : NSManagedObject {
  /*
             class func getContext () -> NSManagedObjectContext {
        let appDelegate = UIApplication.shared.delegate as! AppDelegate

        let moc = NSManagedObjectContext(concurrencyType:.mainQueueConcurrencyType)
        let privateMOC = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
        privateMOC.parent = moc

        privateMOC.perform({
            do {
                try privateMOC.save()
            } catch {
                fatalError("Failure to save context: \(error)")
            }
        })
        return appDelegate.persistentContainer.viewContext
    }
             */ // tried this but didn't work

     class func getContext () -> NSManagedObjectContext {
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        return appDelegate.persistentContainer.viewContext
    }

这就是我的使用方式，下面只是在数据库中保存数据的一个示例。

class func SaveCustomerContacts(name : String,id : String){

let context = getContext()
let entity =  NSEntityDescription.entity(forEntityName: "AllCustomerContacts_Tbl", in: context)
let newDoc = NSManagedObject(entity: entity!, insertInto: context)

newDoc.setValue(name, forKey: "contactName")
newDoc.setValue(id, forKey: "id") 



    //save the object
do {
    try context.save()
    print("saved Customer contacts in Database yayy!")

} catch let error as NSError  {
    print("Could not save \(error), \(error.userInfo)")
} catch {
    let nserror = error as NSError
    fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}

这是抛出的完整异常:

    [error] error: Serious application error.  Exception was caught during Core Data change processing.  This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification.  -[__NSCFSet addObject:]: attempt to insert nil with userInfo (null)
CoreData: error: Serious application error.  Exception was caught during Core Data change processing.  This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification.  -[__NSCFSet addObject:]: attempt to insert nil with userInfo (null)
2017-07-31 16:09:20.908 Sales CRM[5846:202190] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFSet addObject:]: attempt to insert nil'
*** First throw call stack:

Answer 1

错误表明一些 nil 值被插入。

[error] error: Serious application error.  Exception was caught during Core Data change processing.  This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification.  -[__NSCFSet addObject:]: attempt to insert nil with userInfo (null)
CoreData: error: Serious application error.  Exception was caught during Core Data change processing.  This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification.  -[__NSCFSet addObject:]: attempt to insert nil with userInfo (null)
2017-07-31 16:09:20.908 Sales CRM[5846:202190] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFSet addObject:]: attempt to insert nil'
*** First throw call stack:

这个问题可能有多种原因:

1. 您正在使用多个上下文并且没有正确处理它们。
2. 您正在尝试在后台保存具有并发类型 MainQueueConcurrencyType 的上下文。请改用 PrivateQueueConcurrencyType。
3. 保存的值是 nil 或某种错误数据(在关系中)。