如何获取节中的对象数NSFetchedResultsController Swift

Question

如何获取Swift中NSFetchedResultcController节的对象数？

if let s = self.fetchedResultsController?.sections as? NSFetchedResultsSectionInfo { 

    } 

是给我Cannot downcast from '[AnyObject]' to non-@objc protocol type NSFetchedResultsSectionInfo

var d = self.fetchedResultsController?.sections[section].numberOfObjects 

给我does not have member named 'subscript'

Answer 1

你需要投self.fetchedResultsController?.sections到NSFetchedResultsSectionInfo的Array对象：

if let s = self.fetchedResultsController?.sections as? [NSFetchedResultsSectionInfo] 

然后，你可以通过section到t他下标并获得对象的数量：

if let s = self.fetchedResultsController?.sections as? [NSFetchedResultsSectionInfo] { 
    d = s[section].numberOfObjects 
} 

Answer 2

我认为麦克S中目前公认的答案是预雨燕2.0

以下是为我工作（雨燕2.1）：

if let sections = fetchedResultsController?.sections { 
    return sections[section].numberOfObjects 
} else { 
    return 0 
}