我已在我的应用程序中实现了消息传递功能，但只有在设置为我的初始视图控制器

Question

我的应用程序的布局是用户需要使用电子邮件和密码（firebase）登录，然后会显示导航栏。当我单击导航栏上的消息选项卡时，没有任何内容出现，它只是空的。当我将消息视图设置为我的初始视图控制器时，消息功能出现并允许我发送消息。

我该如何解决这个问题？我正在使用JSQMessaging

以下是我的＆＃34; ChatViewController＆＃34;中的代码。当我通过loginVC注册时，主屏幕会打开一个导航栏。 bar ...当我点击导航栏中的消息时，屏幕显示为全白：

import UIKit
import JSQMessagesViewController
import FirebaseDatabase
import FirebaseAuth


class ChatViewController: JSQMessagesViewController  {
    var messages = [JSQMessage]()



    override func viewDidLoad() {
        super.viewDidLoad()

        let currentUser = Auth.auth().currentUser


        self.senderId = currentUser!.uid
        self.senderDisplayName = "Hi"






        // Do any additional setup after loading the view.
    }






    override func didPressSend(_ button: UIButton!, withMessageText text: String!, senderId: String!, senderDisplayName: String!, date: Date!) {
        print("didPressSend")
        print("\(text)")
        messages.append(JSQMessage(senderId: senderId, displayName: senderDisplayName, text: text))
        collectionView.reloadData()
        print(messages)

    }

    override func didPressAccessoryButton(_ sender: UIButton!) {
        print("AccessoryButton")
        let imagePicker = UIImagePickerController()
        imagePicker.delegate = self
        self.present(imagePicker, animated: true, completion: nil)
    }

    override func collectionView(_ collectionView: JSQMessagesCollectionView!, messageDataForItemAt indexPath: IndexPath!) -> JSQMessageData! {
        return messages[indexPath.item]
    }




    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = super.collectionView(collectionView, cellForItemAt: indexPath) as! JSQMessagesCollectionViewCell
        return cell
    }


    override func collectionView(_ collectionView: JSQMessagesCollectionView!, messageBubbleImageDataForItemAt indexPath: IndexPath!) -> JSQMessageBubbleImageDataSource! {
        let message = messages[indexPath.item]
        if message.senderId == self.senderId{let bubbleFactory = JSQMessagesBubbleImageFactory()
            return bubbleFactory?.outgoingMessagesBubbleImage(with: .black)
        } else {
            let bubbleFactory = JSQMessagesBubbleImageFactory()
            return bubbleFactory?.outgoingMessagesBubbleImage(with: .blue)
        }


    }

    override func collectionView(_ collectionView: JSQMessagesCollectionView!, avatarImageDataForItemAt indexPath: IndexPath!) -> JSQMessageAvatarImageDataSource! {
        return nil
    }

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        print(messages.count)
        return messages.count
    }



    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}

extension ChatViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        print("did finish picking")
        print(info)
        let picture = info[UIImagePickerControllerOriginalImage] as? UIImage
        let photo = JSQPhotoMediaItem(image: picture!)

        messages.append(JSQMessage(senderId: senderId, displayName: senderDisplayName, media: photo))
        self.dismiss(animated: true, completion: nil)
        collectionView.reloadData()
    }
}