检索帖子/查询firebase swift 4

Question

我正在尝试从firebase检索帖子列表（＆＃34; Planits - 以我的应用语言＆＃34;）。我的目标是在其个人资料的表格视图中显示特定用户帖子。我编写了一个函数来检索帖子并通过发件人ID查询它们，以便用户在他们的个人资料中查看他们的帖子。但在查询结束时，当我尝试打印出附加的数组时，我不断得到一个空数组，所以我无法继续填充表视图。请关于我哪里出错的任何建议，附件是我的firebase节点的屏幕截图和我写的功能。感谢

func retrievePost(){

   ref = Database.database().reference()

    let myPlanitsRef = self.ref.child("planits")

    let query = myPlanitsRef.queryOrdered(byChild: "senderId").queryEqual(toValue: "uid")
    print(query)

    query.observeSingleEvent(of: .value, with: { (snapshot) in
        if snapshot.exists() {

            for child in snapshot.children {
            let snap = child as! DataSnapshot
                print(DataSnapshot.self)
            let dict = snap.value as! [String: Any]
                let myPostURL = dict["images"] as! String
                self.images.append(myPostURL)

            }

            //print(myPostURL) - DOES NOT PRING ANYTHING
            //print(self.images) - DOES NOT PRING ANYTHING
        }


    }) { (error) in
        print(error)
    }

}
 override func viewDidLoad() {
        super.viewDidLoad()

        retrievePost()
        print(images) // PRINTS []