这是我的NSFetchedResultsControllerDelegate，有一些印刷品：
//MARK: - NSFetchedResultsControllerDelegate
func controllerWillChangeContent(controller: NSFetchedResultsController) {
tableView.beginUpdates()
}
func controller(controller: NSFetchedResultsController, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType) {
let indexSet = NSIndexSet(index: sectionIndex)
switch type {
case .Insert:
print("SECTION INSERT --->>> \(sectionIndex)")
tableView.insertSections(indexSet, withRowAnimation: .Fade)
case .Delete:
tableView.deleteSections(indexSet, withRowAnimation: .Fade)
case .Update:
fallthrough
case .Move:
tableView.reloadSections(indexSet, withRowAnimation: .Fade)
}
}
func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
switch type {
case .Insert:
if let newIndexPath = newIndexPath {
print("ROW INSERT --->>> \(newIndexPath)")
tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Fade)
}
case .Delete:
if let indexPath = indexPath {
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
}
case .Update:
if let indexPath = indexPath {
tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
}
case .Move:
if let indexPath = indexPath, let newIndexPath = newIndexPath {
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Fade)
}
}
print("First sumOfRows --->>> \(fetchedResultsController.fetchedObjects?.count)")
var sumOfRows = 0
for section in fetchedResultsController.sections! {
sumOfRows += section.objects!.count
}
print("Second sumOfRows--->>> \(sumOfRows)")
}
func controllerDidChangeContent(controller: NSFetchedResultsController) {
tableView.endUpdates()
}
//MARK: - UITableViewDataSource
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return fetchedResultsController?.sections?.count ?? 0
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("Section --->>> \(section)")
print("Number of rows in section --->>> \(fetchedResultsController.sections![section].objects!.count)")
return fetchedResultsController.sections![section].objects!.count
}
BEFORE 插入我只有一个部分，其中有一行。
当我插入新行时，控制台上的输出如下：
SECTION INSERT --->>> 1
ROW INSERT --->>> <NSIndexPath: 0xc000000000000116> {length = 2, path = 1 - 0}
First sumOfRows --->>> Optional(2)
Second sumOfRows--->>> 3
Section --->>> 0
Number of rows in section --->>> 2
Section --->>> 1
Number of rows in section --->>> 1
我得到错误：
CoreData：错误：严重的应用程序错误。在调用-controllerDidChangeContent：期间，从NSFetchedResultsController的委托中捕获到异常。无效更新：第0节中的行数无效。更新（2）后现有部分中包含的行数必须等于更新前该部分中包含的行数（1），加上或减去数字从该部分插入或删除的行（0插入，0删除）和加或减移入或移出该部分的行数（0移入，0移出）。 with userInfo（null）
为什么NSFetchedResultsController在部分中返回错误的行数？