也许有人有大型核心数据库的工作经验(我在我的基础中有32k行,我需要向用户展示所有这些基础并在其中进行一些搜索),当我尝试读取基地到我fetchedResultsController我有3-5秒的延迟,我该如何解决这个问题? 我可以在一些后台线程中读取这个基地吗? 或者如果我通过关系将部分零件分离出来,对它有帮助吗? 我尝试在viewDidAppear通过fetchedResultsController在核心数据中处理大型基数
override func viewDidAppear(_ animated: Bool) {
DispatchQueue.main.async {
self.connectFetchedRequest()
self.tableView.reloadData()
self.indicatorLoad.stopAnimating()
}
}
func connectFetchedRequest() {
do {
try self.fetchedResultsController.performFetch()
}catch {
print(error)
}
}
我使用UISearchBarDelegate方法(但我仍然有一些“滞后”,当角色的SEARCHTEXT添加)
func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
block?.cancel()
block = DispatchWorkItem {
let predicate = NSPredicate(format: "cardName contains[c] %@", searchText)
self.fetchedResultsController.fetchRequest.predicate = predicate
self.connectFetchedRequest()
DispatchQueue.main.async(execute: {
self.tableView.reloadData()
})
}
DispatchQueue.global(qos: .background).asyncAfter(deadline: .now() + 0.5, execute: block!)
}
我创建加载我基地在基本搜索fetchedResultsController用下面的代码
lazy var context: NSManagedObjectContext = {
let appDelegate = (UIApplication.shared.delegate as? AppDelegate)
return appDelegate!.managedObjectContext
}()
lazy var fetchedResultsController: NSFetchedResultsController<CardsBaseClass> = {
let fetchRequest = NSFetchRequest<CardsBaseClass>(entityName: "CardsBase")
let sortDescriptor = NSSortDescriptor(key: "cardName", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor]
fetchRequest.fetchBatchSize = 50
fetchRequest.returnsObjectsAsFaults = false
let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: self.context, sectionNameKeyPath: nil, cacheName: nil)
fetchedResultsController.delegate = self
return fetchedResultsController
}()
从其他的viewController增加新的谓词(我打开.overFullScreen与浅,所以我的主视图e是开得)我用下面的代码
predicateArrayClass.addPredicate(predicate: predicateType)
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "updateTableViewByNewPredicate"), object: nil, userInfo: nil)
self.dismiss(animated: true, completion: nil)
其中i称为更新fetchResultController FUNC
func updateTableViewByNewPredicate() {
searchController.searchBar.text! = ""
let predicateArray = predicateArrayClass.arrayOfPredicates
block = DispatchWorkItem {
self.fetchedResultsController.fetchRequest.predicate = NSCompoundPredicate(andPredicateWithSubpredicates: predicateArray)
self.connectFetchedRequest()
DispatchQueue.main.async(execute: {
self.tableView.reloadData()
})
}
DispatchQueue.global(qos: .background).async(execute: block!)
}
你可以编辑你的问题来添加你创建读取结果控制器的代码吗?如何配置它可能是一个关键细节。添加了 –
,并且还使用NSFetcherResultControllerDelegate方法更新tableView数据(controllerWillChangeContent,controllerDidChangeContent和didChangeObject)。我在“茶壶”的答案中添加了代码,但加载时间仍然是几秒钟 – Skie