arrays - 将 PFObject append 到数组，导致所有元素被替换(Swift、Parse)

Question

我正在使用 Parse 设置用户对并将matchedRelation 保存在UserRelations 类中。但是，我发现一个奇怪的问题，当将 PFObject append 到 PFObject Array 时，该数组中的所有元素都会被替换，而使用 AnyObject Array 时完全没问题。请帮我找出问题所在。

query.findObjectsInBackgroundWithBlock { (objects: [AnyObject]!, error: NSError!) -> Void in
        if error == nil {
            var pairRelation = PFObject (className: "UserRelations")
            var pairRelations = [PFObject]()
            var testArray = [AnyObject]()

            for object in objects {

                pairRelation.setObject(object.username, forKey: "toUser")
                pairRelation.setObject(PFUser.currentUser()!, forKey: "fromUser")
                pairRelation.setObject(true, forKey: "isMatched")

                pairRelations.append(pairRelation)
                testArray.append(object.username)

                println("After append the results of the Array is: \(pairRelations)")
                println("\nAfter append the results of the test Array is: \(testArray)")

            }
        } 
    }

前三场比赛的输出如下所示:

After append the results of the Array is: [<UserRelations: 0x7fe22b0713c0, objectId: new, localId: (null)> {
fromUser = "<PFUser: 0x7fe22b127670, objectId: 3WXg5FUEsE>";
isMatched = 1;
toUser = "asdfsdf@df.sdfss";}, <UserRelations: 0x7fe22b0713c0, objectId: new, localId: (null)> {
fromUser = "<PFUser: 0x7fe22b127670, objectId: 3WXg5FUEsE>";
isMatched = 1;
toUser = "asdfsdf@df.sdfss";}, <UserRelations: 0x7fe22b0713c0, objectId: new, localId: (null)> {
fromUser = "<PFUser: 0x7fe22b127670, objectId: 3WXg5FUEsE>";
isMatched = 1;
toUser = "asdfsdf@df.sdfss";}]

After append the results of the test Array is: 
[andy@gd.com, dfasdf@fsadf.dfs, asdfsdf@df.sdfss]

因此，PFObject 数组在追加后都获得了相同的元素，而花药数组则获得了所有三个不同的用户。感谢您的任何评论/帮助!

Answer 1

您当前正在创建一个名为 pairRelation 的 PFObject 实例。因此，在循环内，您始终会更新内存中的同一对象。

只需将该行移到循环内，以便每次都创建一个新的 PFObject:

query.findObjectsInBackgroundWithBlock { (objects: [AnyObject]!, error: NSError!) -> Void in
        if error == nil {
            var pairRelations = [PFObject]()
            var testArray = [AnyObject]()

            for object in objects {
                var pairRelation = PFObject (className: "UserRelations") //Create new PFObject

                pairRelation.setObject(object.username, forKey: "toUser")
                pairRelation.setObject(PFUser.currentUser()!, forKey: "fromUser")
                pairRelation.setObject(true, forKey: "isMatched")

                pairRelations.append(pairRelation)
                testArray.append(object.username)

                println("After append the results of the Array is: \(pairRelations)")
                println("\nAfter append the results of the test Array is: \(testArray)")

            }
        } 
    }