MessageKit输入栏未显示

Question

我正在使用messagekit和firebase制作具有三个不同消息传递选项卡的应用程序。每个messagekit视图都装入一个容器中。我的问题是Messagekit输入栏未显示。我在下面添加了viewDidLoad（）函数和input函数以及其他图片。让我知道您是否有任何想法，我已经尝试过很多不同的论坛。

This is the issue in the iPhone simulator

This is my storyboard layout.

    override func viewDidLoad() {
    super.viewDidLoad()

    self.title = user2Name ?? "Chat"

    navigationItem.largeTitleDisplayMode = .never
    maintainPositionOnKeyboardFrameChanged = true
    messageInputBar.delegate = self
    messagesCollectionView.messagesDataSource = self
    messagesCollectionView.messagesLayoutDelegate = self
    messagesCollectionView.messagesDisplayDelegate = self

    let db2 = Firestore.firestore().collection("Users").document(currentUser.uid)

    db2.getDocument { (document, error) in
        if let document = document, document.exists {
            let dataDescription = document.data()!["matches"]! as! [Any]
            self.user2UID = dataDescription[0] as! String
            self.loadChat()
        } else {
            print("Document does not exist")
            self.loadChat()
        }
    }

}

            func inputBar(_ inputBar: InputBarAccessoryView, didPressSendButtonWith text: String) {

            let message = Message(id: UUID().uuidString, content: text, created: Timestamp(), senderID: currentUser.uid, senderName: currentUser.displayName!)

              //messages.append(message)
              insertNewMessage(message)
              save(message)

              inputBar.inputTextView.text = ""
              messagesCollectionView.reloadData()
              messagesCollectionView.scrollToBottom(animated: true)
        }