使用动画删除UITableViewCell（错误/崩溃） [英] delete UITableViewCell with animation (error/crash)
问题描述
我想删除 UITableViewCell &来自具有动画的 UITableView 的CoreData对象。我写了这段代码：
func tableView（tableView：UITableView，didSelectRowAtIndexPath indexPath：NSIndexPath）{
let mySelectedCell：UITableViewCell = tableView.cellForRowAtIndexPath（indexPath）！
// 1
让appDelegate = UIApplication.sharedApplication（）。委托为AppDelegate
让managedContext = appDelegate.managedObjectContext！
// 2
let fetchRequest = NSFetchRequest（entityName：Person）
// 3
mySelectedCell.backgroundColor = green
mySelectedCell.detailTextLabel？.text =Done
mySelectedCell.accessoryType = UITableViewCellAccessoryType.Checkmark
let person = people [indexPath.row]
managedContext.deleteObject（person）
self.tableView.deleteRowsAtIndexPaths（[indexPath]，withRowAnimation：.Right）
}
我不知道为什么，但应用程序是崩溃，如果我选择一个单元格，我想删除。
2015-03-29 18：00：10.776 MyApp [3001：79507] *** Assertion failure in - [UITableView _endCellAnimationsWithContext ：]，/SourceCache/UIKit_Sim/UIKit-3318.93/UITableView.m:1582
崩溃行： code> self.tableView.deleteRowsAtIndexPaths（[indexPath]，withRowAnimation：.Right）
有人知道我做了什么错误？
更新：
tableView.beginUpdates（）
var numberItems：Int = people.count
self.tableView.deleteRowsAtIndexPaths（[indexPath]，withRowAnimation：.Right）
numberItems - = [indexPath] .count //类似[indexPath] .count
tableView.endUpdates（）
func tableView（tableView：UITableView，numberOfRowsInSection section： Int） - > Int {
application.applicationIconBadgeNumber = people.count
return people.count
}
新错误：
2015-03-29 19：14：15.972 MyApp [3389：89566] ***在 - [UITableView _endCellAnimationsWithContext：]中的声明失败，/SourceCache/UIKit_Sim/UIKit-3318.93/UITableView.m:1582
在这行代码： tableView.endUpdates（）
如果表视图使用获取结果控制器，那么你有
才能删除对象的只有一件事是删除对象从托管对象上下文：
let context = self.fetchedResultsController.managedObjectContext
context.deleteObject（self.fetchedResultsController .objectAtIndexPath（indexPath）as NSManagedObject）
当然保存上下文以使更改永久。 / p>
然后通过
获取结果控制器委托方法自动更新表视图
func controllerWillChangeContent（controller：NSFetchedResultsController）
func controller（controller：NSFetchedResultsController，didChangeSection sectionInfo：NSFetchedResultsSectionInfo，atIndex sectionIndex：Int，forChangeType type：NSFetchedResultsChangeType）
func controller ：NSFetchedResultsController，didChangeObject anObject：AnyObject，atIndexPath indexPath：NSIndexPath ?, forChangeType type：NSFetchedResultsChangeType，newIndexPath：NSIndexPath？）
func controllerDidChangeContent（controller：NSFetchedResultsController）
您可以在
NSFetchedResultsControllerDelegate 文档，如果您没有
已经实现它们。
此外，您不应该在
people 数组中有一个副本的获取对象。获取的结果控制器在表视图中直接使用
数据源方法，例如：
override func numberOfSectionsInTableView tableView：UITableView） - > Int {
return self.fetchedResultsController.sections？.count？ 0
}
override func tableView（tableView：UITableView，numberOfRowsInSection section：Int） - > int {
let sectionInfo = self.fetchedResultsController.sections！[section] as NSFetchedResultsSectionInfo
return sectionInfo.numberOfObjects
}
override func tableView（tableView：UITableView，cellForRowAtIndexPath indexPath：NSIndexPath） - > UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier（Cell，forIndexPath：indexPath）as UITableViewCell
self.configureCell（cell，atIndexPath：indexPath）
return cell
}
如果您在Xcode
中创建一个全新的Master-Detail + Core Data Application将获得您需要的所有必要的模板代码。
I'd like to delete a UITableViewCell & a CoreData Object from a UITableView with an animation. I wrote this code for doing it:
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let mySelectedCell:UITableViewCell = tableView.cellForRowAtIndexPath(indexPath)!
//1
let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
let managedContext = appDelegate.managedObjectContext!
//2
let fetchRequest = NSFetchRequest(entityName:"Person")
//3
mySelectedCell.backgroundColor = green
mySelectedCell.detailTextLabel?.text = "Done"
mySelectedCell.accessoryType = UITableViewCellAccessoryType.Checkmark
let person = people[indexPath.row]
managedContext.deleteObject(person)
self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Right)
}
I don't know why but the app is crashing if I select a cell, which I want to delete.
2015-03-29 18:00:10.776 MyApp[3001:79507] *** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-3318.93/UITableView.m:1582
Crashing line: self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Right)
Does someone knows what I've done wrong?
Update:
tableView.beginUpdates()
var numberItems:Int = people.count
self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Right)
numberItems -= [indexPath].count // something like [indexPath].count
tableView.endUpdates()
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
application.applicationIconBadgeNumber = people.count
return people.count
}
New error:
2015-03-29 19:14:15.972 MyApp[3389:89566] *** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-3318.93/UITableView.m:1582
in this line of code: tableView.endUpdates()
If the table view displays Core Data objects using a fetched results controller then the only thing you have to do to delete an object is to delete the object from the managed object context:
let context = self.fetchedResultsController.managedObjectContext
context.deleteObject(self.fetchedResultsController.objectAtIndexPath(indexPath) as NSManagedObject)
and of course save the context to make the change permanent.
Updating the table view is then done "automatically" by the fetched results controller delegate methods
func controllerWillChangeContent(controller: NSFetchedResultsController)
func controller(controller: NSFetchedResultsController, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType)
func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?)
func controllerDidChangeContent(controller: NSFetchedResultsController)
You'll find a typical implementation of these methods in the NSFetchedResultsControllerDelegate documentation, if you haven't implemented them already.
Also you should not have a "copy" of the fetched objects in your
people array. The fetched results controller is directly used
in the table view data source methods, for example:
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return self.fetchedResultsController.sections?.count ?? 0
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
let sectionInfo = self.fetchedResultsController.sections![section] as NSFetchedResultsSectionInfo
return sectionInfo.numberOfObjects
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
self.configureCell(cell, atIndexPath: indexPath)
return cell
}
If you create a fresh "Master-Detail + Core Data Application" in Xcode then you'll get all the necessary template code that you need.
这篇关于使用动画删除UITableViewCell（错误/崩溃）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
