我正在描述核心数据图中的一些颜色信息。实体是颜色,属性是颜色组件。
我在两个方面苦苦挣扎:如何从图表中删除颜色对象,其次,(奖金问题?),我如何识别重复的颜色?
在我的AppDelegate中,我有一个像这样的核心数据堆:
lazy var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "DD")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// Replacing this implementation with code to handle the error appropriately.
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
// MARK: - Core Data Saving support
func saveContext () {
print(#function)
let context = persistentContainer.viewContext
if context.hasChanges {
do {
try context.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
在我试图删除颜色的地方,我有这个:
func deleteColor(_ sender:UIButton) {
let i : Int = (sender.layer.value(forKey: "index")) as! Int
print(#function, "object to delete: ", i)
let managedContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
colors.remove(at: i)
do {
try managedContext.save()
} catch let error as NSError {
print("Error While Saving Data: \(error.userInfo)")
}
recentColorCollection!.reloadData()
}
变量是:
var colors = [RecentColorEntity]()
var colorEntity = "RecentColorEntity"
我没有收到任何错误,但是对象没有被删除..有人可以帮我弄清楚我做错了吗
答案 0 :(得分:1)
context.delete(colorObject)
只是从内存中的颜色数组中删除颜色。您需要删除实际对象,例如
ArrayAdapter
并保存。