ios - 当我尝试向 PFRelation 添加新对象时应用挂起

Question

我正在尝试向 PFRelation 添加一个对象。我想我已经检查了最常见的问题，我尝试添加的对象已经在解析时保存了。此外，关系在解析中指向与我要添加的对象类型相同的类。

代码

func tapToJoin() {
    dispatch_async(queue) { () -> Void in
        if let user = User.localUsername() {
            joinToEvent(user, toEventWithId: eventId) { (success) in
                dispatch_async(dispatch_get_main_queue(), { () -> Void in
                    if success {
                        SVProgressHUD.showSuccessWithStatus("Joined")
                    } else {
                        SVProgressHUD.showErrorWithStatus("Error")
                    }
                })
            }
        }
    }
}

func joinToEvent(user:User,toEventWithId eventId:String, complete:(Bool)->Void){
    do {
        //1. query event
        let eventQuery = PFQuery(className: "Event", predicate: NSPredicate(format: "objectId = %@",eventId))
        let event = try eventQuery.findObjects().first
        //2. find user
        let userQuery = PFQuery(className: "User", predicate: NSPredicate(format: "objectId = %@",user.id))
        let parseUser = try userQuery.findObjects().first!
        //3. add user to event.participants
        let eventParticipants = event?.objectForKey("participants") as! PFRelation
        eventParticipants.addObject(parseUser)
        //4. save event to parse
        try event?.save()
        complete(true)
    } catch {
        complete(false)
    }
}

问题

应用在 eventParticipants.addObject(parseUser) 挂起。我不确定应该如何处理这个问题。

Answer 1

至少有一个问题是 eventParticipants 应该用 event.relationForKey 初始化，而不是 objectForKey