在Swift中的ios – parse.com – 是否可以将检索到的PFObject转
发布时间:2020-12-14 02:23:24 所属栏目:百科 来源:网络整理
导读:我已经创建了一个PFObject的子类,基本上遵循了 parse.com docs上的指令,并在本地固定了对象.解析文档似乎没有用于检索PFObject子类,我想知道 – 是否可以将检索到的对象转换为PFObject子类.如果是这样,怎么样? (我知道如果不可能,可能需要根据PFObject的检
我已经创建了一个PFObject的子类,基本上遵循了
parse.com docs上的指令,并在本地固定了对象.解析文档似乎没有用于检索PFObject子类,我想知道 – 是否可以将检索到的对象转换为PFObject子类.如果是这样,怎么样?
(我知道如果不可能,可能需要根据PFObject的检索属性重新实例化子类.) let query = PFQuery(className:Armor.parseClassName()) query.fromLocalDatastore() query.findObjectsInBackgroundWithBlock({ (objects:[AnyObject]?,error: NSError?) in if let error = error { // There was an error } else { if let objects = objects as? [PFObject] { for object in objects { //This println is outputting to the console: println("PFObject object retrieved") if let object = object as? Armor { //This println is NOT outputting to the console: println("PFObject object cast as Armor") } } } } })
确保您已在应用程序中注册了子类:didFinishLaunchingWithOptions:.在我的例子中,它不会将检索到的对象强制转换为PFObject子类.
func application(application: UIApplication,didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { Armor.registerSubclass() Parse.enableLocalDatastore() Parse.setApplicationId(...,clientKey: ...) return true } AppDelegate.swift func application(application: UIApplication,didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { CatsObject.registerSubclass() Parse.enableLocalDatastore() Parse.setApplicationId("...",clientKey: "...") return true } CatsObject.swift import Foundation class CatsObject: PFObject,PFSubclassing { static func parseClassName() -> String { return "Cat" } } CatViewController.swift override func viewDidLoad() { queryData() } func queryData() { let query = PFQuery(className: CatsObject.parseClassName()) query.fromLocalDatastore() query.findObjectsInBackgroundWithBlock({ (objects:[AnyObject]?,error: NSError?) in if let error = error { // There was an error } else { println("count local objects = (objects?.count)") if let objects = objects as? [PFObject] { for object in objects { println("PFObject object retrieved") if object is CatsObject { println("object is CatsObject subclass") } if let object = object as? CatsObject { println("PFObject object cast as CatsObject") } } } } }) } 控制台输出 count local objects = Optional(10) PFObject object retrieved object is CatsObject subclass PFObject object cast as CatsObject (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |