Ios NSNumber=0的谓词
我有以下代码从核心数据中获取结果以填充tableviewIos NSNumber=0的谓词,ios,core-data,nspredicate,Ios,Core Data,Nspredicate,我有以下代码从核心数据中获取结果以填充tableview private lazy var fetchedResultsController: NSFetchedResultsController = { // Initialize Fetch Request let fetchRequest = NSFetchRequest(entityName: "MileageLog") // Add Sort Descriptors let dateSort = NSS
private lazy var fetchedResultsController: NSFetchedResultsController = {
// Initialize Fetch Request
let fetchRequest = NSFetchRequest(entityName: "MileageLog")
// Add Sort Descriptors
let dateSort = NSSortDescriptor(key: "logDate", ascending: true)
let mileSort = NSSortDescriptor(key: "mileage", ascending: true)
fetchRequest.sortDescriptors = [dateSort, mileSort]
//// Create a new predicate that filters out any object that
//// have not been exported.
// let predicate = NSPredicate(format: "wasExported == %@", 0)
//// Set the predicate on the fetch request
// fetchRequest.predicate = predicate
let delegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedObjectContext = delegate.managedObjectContext
// Initialize Fetched Results Controller
let fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: managedObjectContext, sectionNameKeyPath: nil, cacheName: nil)
fetchedResultsController.delegate = self
return fetchedResultsController
}()
如果没有谓词,tableview将填充正确排序的所有记录。取消对这两行的注释以使谓词生效不会返回任何结果。我的数据集有4条WASExport==1的记录和3条WASExport==0的记录。。。WASExport是一个布尔值,但在核心数据中它存储为NSNumber。。。。。我做错了什么?您在谓词中使用了错误的格式说明符。你想要:
let predicate = NSPredicate(format: "wasExported == %d", 0)
%@
用于对象指针。使用%@
,0
被解释为nil
指针。您在谓词中使用了错误的格式说明符。你想要:
let predicate = NSPredicate(format: "wasExported == %d", 0)
%@
用于对象指针。使用%@
,0
被解释为nil
指针。在这种特殊情况下,它不会有什么区别,但实际上应该是%ld
,compare。在这种特殊情况下,它不会有区别,但实际上应该是%ld
,compare。