I have a subclass of PFUser - MYUser class with implementation of Equatable function for comparing objectIds this way:
func ==(left: MYUser, right: MYUser) -> Bool {
return left.objectId == right.objectId
}
But when I call Array.contains() method it doesn't call this implementation of Equatable function, that leads to incorrect results. For instance, here:
let hasUser = self.selectedUsers.contains(currentUser)
hasUser becomes false if selectedUsers array contains different memory object but with the same objectId as in currentUser.
What interesting, Equatable function implementation is called in direct usage. Here:
var hasUser = false
for itUser in self.selectedUsers {
if itUser == currentUser {
hasUser = true
break
}
}
== operator successfully was called and hasUser has correct values for different memory objects but with the same objectId
What can be the cause of it?
UPDATE. Here is MYUser class:
class MYUser: PFUser {
// MARK: - Parse Object
@NSManaged var avatarFile: PFFile?
@NSManaged var fullName: String?
// MARK: - PFSubclassing Methods (through PFUser)
override class func initialize() {
struct Static {
static var onceToken : dispatch_once_t = 0;
}
dispatch_once(&Static.onceToken) {
self.registerSubclass()
}
}
}
func ==(left: MYUser, right: MYUser) -> Bool {
return left.objectId == right.objectId
}
I think is this a NSObject
issue.
class MYUserNSObject: NSObject {
dynamic var fullName: String
init(fullName: String) {
self.fullName = fullName
super.init()
}
}
func ==(left: MYUserNSObject, right: MYUserNSObject) -> Bool {
return left.fullName == right.fullName
}
let objectUsers = [MYUserNSObject(fullName: "a"), MYUserNSObject(fullName: "b")]
let objectResult = objectUsers.contains(MYUserNSObject(fullName: "a"))
print("\(result)")
Prints false.
class MYUserSwift: Equatable {
var fullName: String
init(fullName: String) {
self.fullName = fullName
}
}
func ==(left: MYUserSwift, right: MYUserSwift) -> Bool {
return left.fullName == right.fullName
}
let swiftUsers = [MYUserSwift(fullName: "a"), MYUserSwift(fullName: "b")]
let swiftResult = swiftUsers.contains(MYUserSwift(fullName: "a"))
print("\(swiftResult)")
Prints true.
Finally, by adding -isEqual:
, I fixed this.
class MYUserNSObject: NSObject {
dynamic var fullName: String
init(fullName: String) {
self.fullName = fullName
super.init()
}
override func isEqual(object: AnyObject?) -> Bool {
guard let user = object as? MYUserNSObject else { return false }
return self == user
}
}
func ==(left: MYUserNSObject, right: MYUserNSObject) -> Bool {
return left.fullName == right.fullName
}
let objectUsers = [MYUserNSObject(fullName: "a"), MYUserNSObject(fullName: "b")]
let objectResult = objectUsers.contains(MYUserNSObject(fullName: "a"))
print("\(objectResult)")
Prints true.
Updated for Swift 4.0
class MYUserNSObject: NSObject {
@objc var fullName: String
init(fullName: String) {
self.fullName = fullName
super.init()
}
override func isEqual(_ object: Any?) -> Bool {
guard let user = object as? MYUserNSObject else { return false }
return self.fullName == user.fullName
}
}
let objectUsers = [MYUserNSObject(fullName: "a"), MYUserNSObject(fullName: "b")]
let objectResult = objectUsers.contains(MYUserNSObject(fullName: "a"))
print("\(objectResult)")
Prints true.
Note: there is no longer a ==(left:right:)
function needed.
let success = MYUserNSObject(fullName: "a") == objectUsers[0]
print("success should be true: \(success)")
let failure = MYUserNSObject(fullName: "a") == objectUsers[1]
print("failure should be false: \(failure)")
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