无法转换 'JSQPhotoMediaItem?' 类型的值？到预期的参数类型“字符串？”

Question

我正在尝试在 Xcode (Swift) 中使用 Firebase 实现 JSQMessageViewController。

我收到一个错误：无法转换“JSQPhotoMediaItem”类型的值？从下面的代码到预期的参数类型'String？'：

func observeMessages() {
    messageRef.observe(.childAdded) { (snapshot) in
        //print(snapshot.value)
        if let dict = snapshot.value as? [String: AnyObject] {
            let mediaType = dict["MediaType"] as! String
            let senderId = dict["senderId"] as! String
            let senderName = dict["senderName"] as! String

            switch mediaType {

            case "TEXT":
                let text = dict["text"] as! String
                self.messages.append(JSQMessage(senderId: senderId, displayName: senderName, text: text))
            case "PHOTO":
                let fileUrl = dict["fileUrl"] as! String
                let url = NSURL(string: fileUrl)
                let data = NSData(contentsOf: url! as URL)
                let picture = UIImage(data: data! as Data)
                let photo = JSQPhotoMediaItem(image: picture)
                self.messages.append(JSQMessage(senderId: senderId, displayName: senderName, text: photo))

            default:
                print("unknown data type")
            }
            self.collectionView.reloadData()
        }
    }
}

Answer 1

您应该在JSQMessage 的初始化程序中将text 更改为media：

self.messages.append(JSQMessage(senderId: senderId, displayName: senderName, media: photo))

仅供参考，JSQMessagesViewController 已弃用。 See this blog post for more information.