在保持NSFetchedResultController功能的同时保存单个CoreData实体(不是整个上下文)

let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
context.perform {
    let entity = context.object(with: managedObjectID) as! YourEntity
    // 修改实体属性
    try? context.save()
}

let fetchRequest: NSFetchRequest<YourEntity> = YourEntity.fetchRequest()
// 设置查询条件
let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
fetchedResultsController.delegate = self
fetchedResultsController.performFetch { (error) in
    if let error = error {
        print("Error fetching data: \(error.localizedDescription)")
    }
}

let entity = fetchedResultsController.object(at: indexPath)
entity.property = newValue
try? context.save()

let indexPath = fetchedResultsController.indexPath(forObject: entity)
tableView.reloadRows(at: [indexPath], with: .automatic)