【发布时间】：2015-06-26 12:53:21
【问题描述】：
我想创建一个包含两个部分的 tableView。每个部分将由不同的 NSFetchResultController 填充。我的数据库中有一个名为“newsItem”的实体。在第一部分中，我想显示前五个 newsItems，其中一个名为“main_article”的属性等于 true。第二部分将是所有 newsItems。
这是我的 NSFetchResultControllers
private lazy var fetchedResultsController: NSFetchedResultsController? = { [unowned self] in
let fetchRequest = NSFetchRequest(entityName: "NewsItem")
let context = self.managedObjectContext
fetchRequest.sortDescriptors = [NSSortDescriptor(key: "date", ascending: false)]
fetchRequest.predicate = NSPredicate(format: "main_article = YES")
fetchRequest.fetchLimit = 5
let controller = NSFetchedResultsController(fetchRequest: fetchRequest,managedObjectContext: context,sectionNameKeyPath: nil,cacheName: nil)
controller.delegate = self
controller.performFetch(nil)
return controller
}()
private lazy var newsroomFetchedResultsController: NSFetchedResultsController? = { [unowned self] in
let fetchRequest = NSFetchRequest(entityName: "NewsItem")
let context = self.managedObjectContext
fetchRequest.sortDescriptors = [NSSortDescriptor(key: "date", ascending: false)]
fetchRequest.fetchBatchSize = 100
let controller = NSFetchedResultsController(fetchRequest: fetchRequest,managedObjectContext: context,sectionNameKeyPath: nil,cacheName: nil)
controller.delegate = self
controller.performFetch(nil)
return controller
}()
NSFetchResultController 委托方法
func controllerWillChangeContent(controller: NSFetchedResultsController) {
self.tableView.beginUpdates()
}
func controller(controller: NSFetchedResultsController,didChangeObject object: AnyObject,atIndexPath indexPath: NSIndexPath?,forChangeType type: NSFetchedResultsChangeType,
newIndexPath: NSIndexPath?) {
switch type {
case .Insert:
self.tableView.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: .Automatic)
case .Update:
self.tableView.reloadRowsAtIndexPaths([indexPath!], withRowAnimation: .Automatic)
case .Move:
self.tableView.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: .Automatic)
self.tableView.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: .Automatic)
case .Delete:
self.tableView.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: .Automatic)
default:
return
}
}
func controllerDidChangeContent(controller: NSFetchedResultsController) {
self.tableView.endUpdates()
}
TableView 委托方法
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 2
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if section == 0 {
return fetchedResultsController?.fetchedObjects?.count ?? 0
}else {
return newsroomFetchedResultsController?.fetchedObjects?.count ?? 0
}
}
func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
if section == 1 {
return (tableView.dequeueReusableCellWithIdentifier("section header") as? UITableViewCell)
}
return nil
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
if let newItem = fetchedResultsController?.fetchedObjects?[indexPath.row] as? NewsItem where indexPath.section == 0 {
if let cell = tableView.dequeueReusableCellWithIdentifier("main cell") as? NewMainTableViewCell where indexPath.row == 0{
cell.lblTitle.text = newItem.title
return cell
}
else if let cell = tableView.dequeueReusableCellWithIdentifier("new cell") as? NewTableViewCell{
cell.lblTitle.text = newItem.title
cell.backgroundColor = UIColor.blackColor()
cell.lblTitle.textColor = UIColor.whiteColor()
return cell
}
}
else if let newItem = newsroomFetchedResultsController?.fetchedObjects?[indexPath.row] as? NewsItem where indexPath.section == 1 {
if let cell = tableView.dequeueReusableCellWithIdentifier("new cell") as? NewTableViewCell {
cell.lblTitle.text = newItem.title
cell.backgroundColor = UIColor.whiteColor()
cell.lblTitle.textColor = UIColor.blackColor()
return cell
}
}
return UITableViewCell()
}
func tableView(tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
if section == 1 {
return 30
}
return 0
}
func tableView(tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
return 0.001
}
func tableView(tableView: UITableView, viewForFooterInSection section: Int) -> UIView? {
return UIView(frame: CGRectZero)
}
func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
if indexPath.section == 0 && indexPath.row == 0 {
return UIScreen.mainScreen().bounds.width * 1.1
}else {
return 67
}
}
当我尝试运行它时出现此错误，并且 tableview 显示为空：
*2015-06-26 15:33:29.183 Kathimerini[5023:965439] *** 断言失败 -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit/UIKit-3347.44/UITableView.m:1623*
2015-06-26 15:33:29.183 Kathimerini[5023:965439] CoreData：错误：严重的应用程序错误。在调用 -controllerDidChangeContent: 期间，从 NSFetchedResultsController 的委托中捕获了一个异常。无效更新：第 0 节中的行数无效。更新后现有节中包含的行数 (5) 必须等于更新前该节中包含的行数 (5)，加上或减去数字从该部分插入或删除的行数（1 插入，0 删除）加上或减去移入或移出该部分的行数（0 移入，0 移出）。与 userInfo (null)
【问题讨论】：
标签： ios swift core-data nsfetchedresultscontroller