如何獲取節中的對象數NSFetchedResultsController Swift

Question

如何獲取Swift中NSFetchedResultcController節的對象數？

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

    } 

是給我Cannot downcast from '[AnyObject]' to non-@objc protocol type NSFetchedResultsSectionInfo

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

給我does not have member named 'subscript'

Answer 1

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

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

然後，你可以通過section到t他下標並獲得對象的數量：

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

Answer 2

我認爲麥克S中目前公認的答案是預雨燕2.0

以下是爲我工作（雨燕2.1）：

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