Understanding Facebook-Style Chat Views

Creating a chat application that mimics the functionality of popular messaging platforms like Facebook or WhatsApp can be a complex task. In this article, we’ll delve into the technical aspects of creating such views and explore the best practices for building scalable and maintainable applications.

Introduction to iOS Chat Applications

Before diving into the specifics of creating a chat view, it’s essential to understand the basics of iOS chat applications. A typical chat application consists of two main components: the sender side (also known as the “outgoing” or “left” channel) and the receiver side (also known as the “incoming” or “right” channel). The sender’s end typically displays messages sent by the user, while the receiver’s end displays messages received from others.

Understanding the Requirements

To create a chat view similar to Facebook or WhatsApp, we need to design an interface that can accommodate two channels: one for sending messages and another for receiving messages. This requires us to separate the logic of rendering the sender’s and receiver’s channels into distinct views.

Separating Concerns with View Controllers

In iOS development, it’s a best practice to keep related components and logic separate to maintain scalability and reusability. In our case, we can create two view controllers: one for the sender side (OutgoingViewController) and another for the receiver side (IncomingViewController).

The OutgoingViewController will be responsible for rendering messages sent by the user, while the IncomingViewController will handle displaying incoming messages from others.

Creating a Single-Channel Chat View

However, there’s an alternative approach that allows us to create a single-channel chat view without separating concerns. We can use a technique called “side-by-side” or “dual-column” layout, where we render both the sender’s and receiver’s channels in the same view controller.

To achieve this, we’ll need to implement a custom UITableView subclass that can accommodate two columns: one for sending messages and another for receiving messages. We’ll also need to create separate sections within each column to display messages sent by different users.

Implementing Custom Table Views

Let’s start by creating a basic implementation of the side-by-side table view:

// SideBySideTableViewCell.swift
import UIKit

class SideBySideTableViewCell: UITableViewCell {
    let senderColumn = UIView()
    let receiverColumn = UIView()

    // ...
}

Next, we’ll create a custom UITableView subclass that will handle rendering both columns:

// SideBySideTableViewController.swift
import UIKit

class SideBySideTableViewController: UITableViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        // Set up table view layout
        let sideBySideLayout = SideBySideLayout()
        self.view.addSubview(sideBySideLayout)
    }

    // MARK: - Table view data source methods
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = SideBySideTableViewCell()
        // Configure cell layout and content
        return cell
    }
}

In the above code, we’ve created a custom SideBySideTableViewController that will handle rendering both columns. We’re using a custom SideBySideLayout class to manage the table view’s layout.

Implementing Side-by-Side Layout

Now it’s time to implement the side-by-side layout:

// SideBySideLayout.swift
import UIKit

class SideBySideLayout: UIView {
    let senderColumn = UIView()
    let receiverColumn = UIView()

    init(frame: CGRect) {
        super.init(frame: frame)

        // Configure columns
        senderColumn.frame = CGRect(x: 0, y: 0, width: 200, height: self.bounds.height)
        receiverColumn.frame = CGRect(x: 200, y: 0, width: 200, height: self.bounds.height)

        // Add columns to view
        addSubview(senderColumn)
        addSubview(receiverColumn)

        // Configure column layout
        senderColumn.backgroundColor = .red
        receiverColumn.backgroundColor = .blue

        // ...
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

In the above code, we’ve created a custom SideBySideLayout class that manages the side-by-side layout of our table view.

Integrating with Chat Logic

Now that we have a basic implementation of the side-by-side chat view, it’s time to integrate it with our chat logic. We’ll need to create separate sections within each column to display messages sent by different users.

To achieve this, we can use a technique called “message threading” where we group related messages together based on their sender or conversation ID.

Threading Messages

Let’s implement message threading:

// MessageThreading.swift
import Foundation

class Message {
    let id: UUID
    let text: String
    let sender: String

    init(id: UUID, text: String, sender: String) {
        self.id = id
        self.text = text
        self.sender = sender
    }
}

class MessageThreading {
    var messages: [Message] = []

    func addMessage(message: Message) {
        // Add message to thread
        let threadIndex = messages.firstIndex(where: { $0.id == message.id })
        if let index = threadIndex {
            messages[index].messages.append(message)
        } else {
            messages.append([message])
        }
    }

    func getMessagesForUser(user: String) -> [Message] {
        // Return messages for specific user
        return messages.filter { $0.sender == user }.flatMap { $0.messages }
    }
}

In the above code, we’ve created a MessageThreading class that manages message threading. We can use this class to group related messages together based on their sender or conversation ID.

Conclusion

Creating a chat application similar to Facebook or WhatsApp requires careful consideration of layout, messaging logic, and user experience. In this article, we’ve explored the technical aspects of creating such views and provided a basic implementation of a side-by-side table view with message threading.

While our example is simplified, it should give you a solid foundation for building your own chat applications. Remember to separate concerns, implement custom layouts, and use message threading to efficiently manage large amounts of data.

Last modified on 2023-10-06