ユーザー解析機能が無料になったFirebaseの使い方超入門：Swift製リアルタイムチャットアプリ開発で学ぶ（3/4 ページ）

import UIKit
import JSQMessagesViewController
import Firebase
import FirebaseDatabase
 
class ViewController: JSQMessagesViewController {
    // 省略
 
    override func didPressSendButton(button: UIButton!, withMessageText text: String!, senderId: String!, senderDisplayName: String!, date: NSDate!) {
        inputToolbar.contentView.textView.text = ""
        let ref = FIRDatabase.database().reference()
        ref.child("messages").childByAutoId().setValue(
            ["senderId": senderId, "text": text, "displayName": senderDisplayName])
    }
}

class ViewController: JSQMessagesViewController {
    var messages = [JSQMessage]()
    override func viewDidLoad() {
        super.viewDidLoad()
        senderDisplayName = "A"
        senderId = "Dummy"
        let ref = FIRDatabase.database().reference()
        ref.observeEventType(.Value, withBlock: { snapshot in
            guard let dic = snapshot.value as? Dictionary<String, AnyObject> else {
                return
            }
            guard let posts = dic["messages"] as? Dictionary<String, Dictionary<String, String>> else {
                return
            }
            self.messages = posts.values.map { dic in
                let senderId = dic["senderId"] ?? ""
                let text = dic["text"] ?? ""
                let displayName = dic["displayName"] ?? ""
                return JSQMessage(senderId: senderId,  displayName: displayName, text: text)
            }
            self.collectionView.reloadData()
        })
    }
    // 省略
}

class ViewController: JSQMessagesViewController {
    var messages = [JSQMessage]()
    override func viewDidLoad() {
        super.viewDidLoad()
        senderDisplayName = "B"
        senderId = "Dummy2"
        // 省略
    }
    // 省略
}