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我尝试在大型核心数据库(32万个对象)中创建搜索,但是当我向UISearchBar
添加一些文本时,我有一些延迟(因为我的基础正在使用新搜索Predicate进行更新)如何解决此问题?我如何更新后台线程中的基础?通过searchBar过滤NSFetchedResultController而不加载基地暂停?
fetchedResultController代码
lazy var context: NSManagedObjectContext = {
let appDelegate = (UIApplication.shared.delegate as? AppDelegate)
let context = appDelegate!.managedObjectContext
return context//appDelegate!.managedObjectContext
}()
lazy var fetchedResultsController: NSFetchedResultsController<CardsBaseClass> = {
let fetchRequest = NSFetchRequest<CardsBaseClass>(entityName: "CardsBase")
let sortDescriptor = NSSortDescriptor(key: "cardName", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor]
fetchRequest.predicate = nil
fetchRequest.fetchBatchSize = 50
fetchRequest.returnsObjectsAsFaults = false
//let mainContext = (UIApplication.shared.delegate as? AppDelegate)?.managedObjectContext
let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: self.context, sectionNameKeyPath: nil, cacheName: nil)
fetchedResultsController.delegate = self
return fetchedResultsController
}()
,并添加一些孩子MOC搜索方法
lazy var searchMOC: NSManagedObjectContext = {
let moc = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
moc.parent = self.context
return moc
}()
连接fetchedResultController我用
override func viewDidAppear(_ animated: Bool) {
self.view.gestureRecognizers?.removeAll()
connectFetchedRequest()
}
func connectFetchedRequest() {
indicatorLoad.startAnimating()
context.perform({
do {
try self.fetchedResultsController.performFetch()
DispatchQueue.main.async(execute: {
self.tableView.reloadData()
self.indicatorLoad.stopAnimating()
})
} catch {
print(error)
}
})
}
搜索谓词与下面的代码
更新searchMOC.performAndWait({
if searchText != "" {
let predicate = NSPredicate(format: "\(self.searchPredicateName) contains[c] %@", searchText)
predicateArray.append(predicate)
}
self.fetchedResultsController.fetchRequest.predicate = NSCompoundPredicate(andPredicateWithSubpredicates: predicateArray)
do {
try self.fetchedResultsController.performFetch()
DispatchQueue.main.async(execute: {
self.tableView.reloadData()
})
} catch {
print(error)
}
})
我是否有权使用searchMOC.perform并通过DispatchQueue更新tableView? 我在核心数据实体中用于谓词的所有属性都是“索引的”,但添加搜索文本时我仍有很多滞后
我创建一个新的searchFetchedResultsController与我的孩子managedObjectContext也有这个问题。 我实际上不明白,我也读了关于NSAsynchronousFetchRequest,并不知道如何解决我的问题 – Skie
根据您发布的代码,您使用的是主FRC。 – Mundi
我创建背景MOC,现在我的fetchResultController在后台加载,但现在我有新的错误。 '不能访问提取对象之前-performFetch:' http://stackoverflow.com/questions/40755273/how-can-i-cancel-block-with-fetchedresultscontroller-performfetch-and-stop-per – Skie