Day#21 Chat

前言

昨天引用了许多函式库，今天就来使用他们所提供的功能，真正来实作chatroom内容吧～～

Spinner

RegisterViewController

spinner.show(in: view)

首先我们在画面加上spinner的元件。

接着在之前的程序中，加上更多判断spinner的逻辑。
当该使用者存在时，就把spinner dismiss掉。

DatabaseManager.shared.userExists(with: email, completion: { [weak self] exists in
    guard let strongSelf = self else { // prevent from memory leak
        return
    }

    DispatchQueue.main.async {
        strongSelf.spinner.dismiss()
    }

    guard !exists else {
        strongSelf.alertUserLoginError(message: "user for that email address already exists")
        return
    }

    FirebaseAuth.Auth.auth().createUser(withEmail: email, password: password, completion: { authResult, error in

        guard authResult != nil, error == nil else {
            print("error creating user")
            return
        }

        // data entry
        DatabaseManager.shared.insertUser(with: ChatAppUser(firstName: firstname,
                                                            lastName: lastname,
                                                            emailAddress: email))
        // todo: flow check
        strongSelf.navigationController?.dismiss(animated: true, completion: nil)
    })
})

table view

ConversationViewController

我们将table view的边线，在subview load进来时显示。

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    tableView.frame = view.bounds
}

聊天

终於进到聊天的view controller了！

ChatViewController

首先，先引入函式库。其中MessageKit是一个处理跟聊天相关所有行为的函式库。

import UIKit
import MessageKit

资料结构

struct Message: MessageType {
    var sender: SenderType
    var messageId: String
    var sentDate: Date
    var kind: MessageKind
}

struct Sender: SenderType {
    var photoURL: String // URL
    var senderId: String
    var displayName: String
}

main view controller

class ChatViewController: MessagesViewController {

    // collection of messages
    private var messages = [Message]()
    
    private let selfSender = Sender(photoURL: "",
                                    senderId: "1",
                                    displayName: "Joe Smith")
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        messages.append(Message(sender: selfSender,
                                messageId: "1",
                                sentDate: Date(),
                                kind: .text("Hello world message hello world message hello world message")))
        
        messagesCollectionView.messagesDataSource = self
        messagesCollectionView.messagesLayoutDelegate = self
        messagesCollectionView.messagesDisplayDelegate = self
    }
    

}

Extension

每次都会需要新增，因为我们在上面有将messagesDataSource, messagesLayoutDelegate, messagesDisplayDelegate指派给自己。
因此需要新增以下几个方法:

目前的sender回传为自己。
每个item定义为messageKit中的section
每个section的数量

extension ChatViewController: MessagesDataSource, MessagesLayoutDelegate, MessagesDisplayDelegate {
    func currentSender() -> SenderType {
        return selfSender
    }
    
    func messageForItem(at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> MessageType {
        // MessageKit use section to separate every single message
        return messages[indexPath.section] // a single section, per message
    }
    
    func numberOfSections(in messagesCollectionView: MessagesCollectionView) -> Int {
        return messages.count
    }
    
    
}