由於NSManagedObjectContextObjectsDidChangeNotification導致的運行時錯誤

Question

我一直在刷新數據或在啓動時發生50％的時間（從服務中獲取並保存在coreData中）時出現此運行時錯誤。我已經瀏覽了幾乎所有關於這個問題的解決方案，但其中大部分都在Obj-C中，但我是iOS新手，並且使用了swift。我有大約20個表，並且都使用相同的上下文。

下面是我的代碼：

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 
    } 

這是我如何使用它，下面是在數據庫中保存的數據的一個例子。

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)") 
} 
} 

這被拋出完整的異常：

[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

的錯誤表明一些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: 

可能有多種原因針對此問題：

1. 您正在使用多個情境並不能正確處理它們。
2. 您正試圖在後臺保存併發類型MainQueueConcurrencyType的上下文。改爲使用PrivateQueueConcurrencyType。
3. 保存的值是nil或某種錯誤數據（關係中）。