[英]Parse PFSubclassing not working with Swift
我复制了Subclassing的Parse Swift示例:
class Armor : PFObject, PFSubclassing {
override class func load() {
self.registerSubclass()
}
class func parseClassName() -> String! {
return "Armor"
}
}
我收到以下错误:
/Parse/Armor.swift:11:1: error: type 'Armor' does not conform to protocol 'PFSubclassing'
class Armor : PFObject, PFSubclassing {
^
__ObjC.PFSubclassing:15:28: note: protocol requires function 'object()' with type '() -> Self!'
@objc(object) class func object() -> Self!
^
__ObjC.PFSubclassing:23:52: note: protocol requires function 'objectWithoutDataWithObjectId' with type '(String!) -> Self!'
@objc(objectWithoutDataWithObjectId:) class func objectWithoutDataWithObjectId(objectId: String!) -> Self!
^
__ObjC.PFSubclassing:30:27: note: protocol requires function 'query()' with type '() -> PFQuery!'
@objc(query) class func query() -> PFQuery!
^
__ObjC.PFSubclassing:35:38: note: protocol requires function 'registerSubclass()' with type '() -> Void'
@objc(registerSubclass) class func registerSubclass()
^
/Parse/Armor.swift:14:9: error: 'Armor.Type' does not have a member named 'registerSubclass'
self.registerSubclass()
^ ~~~~~~~~~~~~~~~~
我看到了这个答案: https : //stackoverflow.com/a/24899411/843151并尝试了解决方案没有运气,我得到了同样的错误。
有关为什么会发生这种情况的任何建议? 提前致谢。
我需要在Objective-C桥接头中导入解析PFObject + Subclass.h
#import <Parse/PFObject+Subclass.h>
使用xCode 6.1.1,我能够在没有桥接头的情况下工作。 只是:
import Parse
在模块的顶部。 对于类声明,我确实需要使用@NSManaged作为变量类型,以使它们成功链接到Parse类变量。 像这样:
class PSCategory : PFObject, PFSubclassing {
override class func load() {
self.registerSubclass()
}
class func parseClassName() -> String! {
return "Category"
}
@NSManaged var Name: String
}
然后在我的查询中,所有名称都是动态链接的:
var query = PSCategory.query() // PFQuery(className: "Category")
query.cachePolicy = kPFCachePolicyCacheElseNetwork // kPFCachePolicyNetworkElseCache
query.maxCacheAge = 60 * 60 * 24 // One day, in seconds.
query.findObjectsInBackgroundWithBlock {
(categories: [AnyObject]!, error: NSError!) -> Void in
if error == nil {
for abstractCategory in categories {
let category = abstractCategory as PSCategory
NSLog("Category Name: %@", category.Name)
}
} else {
NSLog("Unable to retrieve categories from local cache or network")
}
}
Parse建议使用initialize()而不是load()
class Armor : PFObject, PFSubclassing {
override class func initialize() {
var onceToken : dispatch_once_t = 0;
dispatch_once(&onceToken) {
self.registerSubclass()
}
}
static func parseClassName() -> String! {
return "Armor"
}
}
从2015年4月27日发布的v1.7.2开始,PFSubclassing目前在Swift中无法正常工作。
我能够通过实现属性的自定义getter和setter作为临时解决方法来实现它 - 这在某种程度上违背了目的,但至少这种方法只会在PFSubclassing为Swift做好准备后才会进行微小的重构。
没有必要将#import <Parse/PFObject+Subclass.h>
到桥接头。 但是,如PFSubclassing Protocol Reference中所示,“ Warning: This method must be called before [Parse setApplicationId:clientKey:]
之前调用Warning: This method must be called before [Parse setApplicationId:clientKey:]
”,您应该在调用Parse.setApplicationId(_:, clientKey:)
之前注册所有PFObject自定义子类。
这是一个名为PFChatLOCMessage的自定义PFObject子类的示例:
// In ProjectName-Bridging-Header.h
#import <Parse/Parse.h>
// In AppDelegate.swift
@UIApplicationMain
final class AppDelegate: UIResponder, UIApplicationDelegate {
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
configureParse()
return true
}
func configureParse() {
registerParseSubclasses()
Parse.setApplicationId("...", clientKey: "...")
}
func registerParseSubclasses() {
PFChatLOCMessage.registerSubclass()
}
}
// In PFChatLOCMessage.swift
private let PFChatLOCMessageClassName = "PFChatLOCMessage"
private let userKey = "user"
class PFChatLOCMessage: PFObject {
var user: PFUser! {
get { return self[userKey] as! PFUser }
set { self[userKey] = newValue }
}
override init() {
super.init()
}
override init(user: PFUser) {
super.init()
self.user = user
}
}
extension PFChatLOCMessage: PFSubclassing {
class func parseClassName() -> String {
return PFChatLOCMessageClassName
}
}
我使用override class func initialize
得到了死锁/挂起 - 尽管在解析文档中建议这样做。
考虑到它,在类的init方法中进行线程化并不是一个好主意 - 你永远不知道这些可能被调用的时间或内容。
这对我有用 - 对于我所有的自定义子类,在我调用parse init方法之前,我将它们显式注册为子类。
通过这种方式,可以很好地定义调用事物的顺序。 此外,它适用于我;)
MyPFObjectSubclass.registerSubclass()
MyPFObjectSubclass2.registerSubclass()
MyPFObjectSubclass3.registerSubclass()
// etc...
let configuration = ParseClientConfiguration {
$0.applicationId = "fooBar"
$0.server = "http://localhost:1337/parse"
}
Parse.initializeWithConfiguration(configuration)
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