App getting crashed while fetching data from core data swift

Question

Here is the full code for fetch data. Here is the code of fetching data from core data. What is the problem here? Please help what is wrong in fetching data

static func getChatMessagesForGroup( groupId : Double) -> [GroupConversationMessage]{
    AppDelegate.getAppDelegate().log.debug("\(groupId)")
    let managedContext = CoreDataHelper.getNSMangedObjectContext()

    var messages = [GroupConversationMessage]()
    var conversationObjects = [NSManagedObject]()
    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: GROUP_CONVERSATION_TABLE_NAME)
    let predicate = NSPredicate(format: "\(GroupConversationMessage.FLD_GROUP_ID) = %@", argumentArray: [StringUtils.getStringFromDouble(decimalNumber : groupId)])
    fetchRequest.predicate = predicate
    let sortDescriptor = NSSortDescriptor(key: GroupConversationMessage.FLD_TIME, ascending: true)
    var sortDescriptors = [NSSortDescriptor]()
    sortDescriptors.append(sortDescriptor)
    fetchRequest.sortDescriptors =  sortDescriptors
    DispatchQueue.main.sync {
        do {
            let results = try managedContext.fetch(fetchRequest)
            conversationObjects = results as! [NSManagedObject]
        } catch let error as NSError {
            AppDelegate.getAppDelegate().log.error("Could not fetch \(error), \(error.userInfo)")
        }
    }

   for i in 0 ..< conversationObjects.count  {
        let message = GroupConversationMessage()
        message.uniqueID = conversationObjects[i].value(forKey: QuickRideMessageEntity.UNIQUE_ID) as? String
        message.id = conversationObjects[i].value(forKey: GroupConversationMessage.FLD_ID) as! Double
        message.groupId = conversationObjects[i].value(forKey: GroupConversationMessage.FLD_GROUP_ID) as! Double
        message.senderId = conversationObjects[i].value(forKey: GroupConversationMessage.FLD_SENDER_ID) as! Double
        message.senderName = conversationObjects[i].value(forKey: GroupConversationMessage.FLD_SENDER_NAME) as? String
        message.message = (conversationObjects[i].value(forKey: GroupConversationMessage.FLD_MESSAGE) as! String)
        message.time = conversationObjects[i].value(forKey: GroupConversationMessage.FLD_TIME) as! Double
        messages.append(message)
    }
    return messages
}

Answer 1

我不确定，但是您正在尝试在获取数据时进行更新或保存，或者您的集合类型可能是不可变的，并且您正在尝试对其进行突变。