Merge branch 'development' into patch-1

CHANGELOG.md

@@ -4,18 +4,22 @@ The changelog for `MessageKit`. Also see the [releases](https://github.com/Messa
 
 --------------------------------------
 
-## [2.0.0](https://github.com/MessageKit/MessageKit/releases/tag/2.0.0-beta.1)
+## Upcoming Release
 
 ### Changed
 
 - Change acl of `handleGesture(touchLocation:)` in `MessageLabel` from internal to open. 
 [#912](https://github.com/MessageKit/MessageKit/pull/912) by [@julienkode](https://github.com/JulienKode)
 
-- Fixed the way that the Strings and UIImages are parsed in the `InputTextView` to prevent crashes in `parseForComponents()`. 
-[#791](https://github.com/MessageKit/MessageKit/pull/791) by [@nathantannar4](https://github.com/nathantannar4)
+## [2.0.0-beta.1](https://github.com/MessageKit/MessageKit/releases/tag/2.0.0-beta.1)
+
+### Changed
 
 - **Breaking Change** Updated codebase to Swift 4.2 [#883](https://github.com/MessageKit/MessageKit/pull/883) by [@nathantannar4](https://github.com/nathantannar4)
 
+- Fixed the way that the Strings and UIImages are parsed in the `InputTextView` to prevent crashes in `parseForComponents()`. 
+[#791](https://github.com/MessageKit/MessageKit/pull/791) by [@nathantannar4](https://github.com/nathantannar4)
+
 ### Added
 
 - Added support for detection and handling of `NSLink`s inside of messages.
@@ -30,15 +34,17 @@ The changelog for `MessageKit`. Also see the [releases](https://github.com/Messa
 - Added `additionalBottomInset` property that allows to adjust the bottom content inset automatically set on the messages collection view by the view controller. 
 [#787](https://github.com/MessageKit/MessageKit/pull/787) by [@andreyvit](https://github.com/andreyvit)
 
+- Added new methods to simplify using of custom messages: `customCellSizeCalculator(for:at:in:)` for `MessagesLayoutDelegate` and `customCell(for:at:in:)` for `MessagesDataSource`.
+[#879](https://github.com/MessageKit/MessageKit/pull/879) by [@realbonus](https://github.com/RealBonus)
+
 ### Fixed
 
--  Fixed a bug that prevented `MessageLabel` from laying out properly when contained by superviews using autolayout.
-[#889](https://github.com/MessageKit/MessageKit/pull/889) by [@marius-serban](https://github.com/marius-serban).
-
-
 - **Breaking Change** Fixed typo of `scrollsToBottomOnKeybordBeginsEditing` to `scrollsToBottomOnKeyboardBeginsEditing`.
 [#856](https://github.com/MessageKit/MessageKit/pull/856) by [@p-petrenko](https://github.com/p-petrenko)
 
+-  Fixed a bug that prevented `MessageLabel` from laying out properly when contained by superviews using autolayout.
+[#889](https://github.com/MessageKit/MessageKit/pull/889) by [@marius-serban](https://github.com/marius-serban).
+
 - Fixed bottom content inset adjustment when using an undocked keyboard on iPad, or when `edgesForExtendedLayout` does not include `.top`, or when a parent container view controller adds extra views at the top of the screen. 
 [#787](https://github.com/MessageKit/MessageKit/pull/787) by [@andreyvit](https://github.com/andreyvit)
 
@@ -49,7 +55,9 @@ The changelog for `MessageKit`. Also see the [releases](https://github.com/Messa
 
 - Fixed `MessagesCollectionView` to allow to use nibs with `MessageReusableView`.
 [#832](https://github.com/MessageKit/MessageKit/pull/832) by [@maxxx777](https://github.com/maxxx777).
-- Fixed multiple crashes at views, when views are being called from another XIB. [#905](https://github.com/MessageKit/MessageKit/pull/905) by [@talanov](https://github.com/talanov).
+
+- Fixed multiple crashes at views, when views are being called from another XIB.
+[#905](https://github.com/MessageKit/MessageKit/pull/905) by [@talanov](https://github.com/talanov).
 
 ## [1.0.0](https://github.com/MessageKit/MessageKit/releases/tag/1.0.0)
 

CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 ### Code of Conduct
 
-Please read our [Code of Conduct](https://github.com/MessageKit/MessageKit/blob/master/Code_of_Conduct.md). 
+Please read our [Code of Conduct](https://github.com/MessageKit/MessageKit/blob/master/CODE_OF_CONDUCT.md). 
 The MessageKit maintainers take this Code of Conduct very seriously. Intolerance, disrespect, harassment, and any form of negativity will not be tolerated.
 
 ### Ways to Contribute

Example/Sources/AppDelegate.swift

@@ -35,6 +35,11 @@ final internal class AppDelegate: UIResponder, UIApplicationDelegate {
         window?.rootViewController = NavigationController(rootViewController: LaunchViewController())
         window?.makeKeyAndVisible()
         
+        if UserDefaults.isFirstLaunch() {
+            // Enable Text Messages
+            UserDefaults.standard.set(true, forKey: "Text Messages")
+        }
+        
         return true
     }
 

Example/Sources/Data Generation/SampleData.swift

@@ -30,6 +30,26 @@ final internal class SampleData {
     static let shared = SampleData()
 
     private init() {}
+    
+    enum MessageTypes: UInt32, CaseIterable {
+        case Text = 0
+        case AttributedText = 1
+        case Photo = 2
+        case Video = 3
+        case Emoji = 4
+        case Location = 5
+        case Url = 6
+        case Phone = 7
+        case Custom = 8
+        
+        static func random() -> MessageTypes {
+            // Update as new enumerations are added
+            let maxValue = Custom.rawValue
+            
+            let rand = arc4random_uniform(maxValue+1)
+            return MessageTypes(rawValue: rand)!
+        }
+    }
 
     let system = Sender(id: "000000", displayName: "System")
     let nathan = Sender(id: "000001", displayName: "Nathan Tannar")
@@ -46,8 +66,6 @@ final internal class SampleData {
     
     let messageImages: [UIImage] = [#imageLiteral(resourceName: "img1"), #imageLiteral(resourceName: "img2")]
 
-    let messageTypes = ["Text", "Text", "Text", "AttributedText", "Location", "Photo", "Emoji", "Video", "URL", "Phone", "Custom"]
-
     let emojis = [
         "👍",
         "😂😂😂",
@@ -116,51 +134,62 @@ final internal class SampleData {
             return date
         }
     }
+    
+    func randomMessageType() -> MessageTypes {
+        let messageType = MessageTypes.random()
 
-    func randomMessage(isCustomEnabled: Bool, allowedSenders: [Sender]) -> MockMessage {
+        if !UserDefaults.standard.bool(forKey: "\(messageType)" + " Messages") {
+            return randomMessageType()
+        }
+        
+        return messageType
+    }
+
+    func randomMessage(allowedSenders: [Sender]) -> MockMessage {
 
         let randomNumberSender = Int(arc4random_uniform(UInt32(allowedSenders.count)))
-        let randomNumberImage = Int(arc4random_uniform(UInt32(messageImages.count)))
-        let randomMessageType = Int(arc4random_uniform(UInt32(messageTypes.count - (isCustomEnabled ? 0 : 1))))
-        let randomNumberLocation = Int(arc4random_uniform(UInt32(locations.count)))
-        let randomNumberEmoji = Int(arc4random_uniform(UInt32(emojis.count)))
         
-        let randomSentance = Lorem.sentence()
         let uniqueID = NSUUID().uuidString
         let sender = allowedSenders[randomNumberSender]
         let date = dateAddingRandomTime()
 
-        switch messageTypes[randomMessageType] {
-        case "Text":
-            return MockMessage(text: randomSentance, sender: sender, messageId: uniqueID, date: date)
-        case "AttributedText":
-            let attributedText = attributedString(with: randomSentance)
+        switch randomMessageType() {
+        case .Text:
+            let randomSentence = Lorem.sentence()
+            return MockMessage(text: randomSentence, sender: sender, messageId: uniqueID, date: date)
+        case .AttributedText:
+            let randomSentence = Lorem.sentence()
+            let attributedText = attributedString(with: randomSentence)
             return MockMessage(attributedText: attributedText, sender: senders[randomNumberSender], messageId: uniqueID, date: date)
-        case "Photo":
+        case .Photo:
+            let randomNumberImage = Int(arc4random_uniform(UInt32(messageImages.count)))
             let image = messageImages[randomNumberImage]
             return MockMessage(image: image, sender: sender, messageId: uniqueID, date: date)
-        case "Video":
+        case .Video:
+            let randomNumberImage = Int(arc4random_uniform(UInt32(messageImages.count)))
             let image = messageImages[randomNumberImage]
             return MockMessage(thumbnail: image, sender: sender, messageId: uniqueID, date: date)
-        case "Emoji":
+        case .Emoji:
+            let randomNumberEmoji = Int(arc4random_uniform(UInt32(emojis.count)))
             return MockMessage(emoji: emojis[randomNumberEmoji], sender: sender, messageId: uniqueID, date: date)
-        case "Location":
+        case .Location:
+            let randomNumberLocation = Int(arc4random_uniform(UInt32(locations.count)))
             return MockMessage(location: locations[randomNumberLocation], sender: sender, messageId: uniqueID, date: date)
-        case "URL":
+        case .Url:
             return MockMessage(text: "https://github.com/MessageKit", sender: sender, messageId: uniqueID, date: date)
-        case "Phone":
+        case .Phone:
             return MockMessage(text: "123-456-7890", sender: sender, messageId: uniqueID, date: date)
-        case "Custom":
+        case .Custom:
             return MockMessage(custom: "Someone left the conversation", sender: system, messageId: uniqueID, date: date)
-        default:
-            fatalError("Unrecognized mock message type")
         }
     }
 
     func getMessages(count: Int, completion: ([MockMessage]) -> Void) {
         var messages: [MockMessage] = []
+        // Disable Custom Messages
+        UserDefaults.standard.set(false, forKey: "Custom Messages")
         for _ in 0..<count {
-            let message = randomMessage(isCustomEnabled: false, allowedSenders: senders)
+            let message = randomMessage(allowedSenders: senders)
             messages.append(message)
         }
         completion(messages)
@@ -168,8 +197,10 @@ final internal class SampleData {
     
     func getAdvancedMessages(count: Int, completion: ([MockMessage]) -> Void) {
         var messages: [MockMessage] = []
+        // Enable Custom Messages
+        UserDefaults.standard.set(true, forKey: "Custom Messages")
         for _ in 0..<count {
-            let message = randomMessage(isCustomEnabled: true, allowedSenders: senders)
+            let message = randomMessage(allowedSenders: senders)
             messages.append(message)
         }
         completion(messages)
@@ -177,8 +208,10 @@ final internal class SampleData {
     
     func getMessages(count: Int, allowedSenders: [Sender], completion: ([MockMessage]) -> Void) {
         var messages: [MockMessage] = []
+        // Disable Custom Messages
+        UserDefaults.standard.set(false, forKey: "Custom Messages")
         for _ in 0..<count {
-            let message = randomMessage(isCustomEnabled: false, allowedSenders: allowedSenders)
+            let message = randomMessage(allowedSenders: allowedSenders)
             messages.append(message)
         }
         completion(messages)

Example/Sources/Models/MockSocket.swift

@@ -77,7 +77,9 @@ final class MockSocket {
             queuedMessage = nil
         } else {
             let sender = arc4random_uniform(1) % 2 == 0 ? connectedUsers.first! : connectedUsers.last!
-            queuedMessage = MockMessage(text: Lorem.sentence(), sender: sender, messageId: UUID().uuidString, date: Date())
+            SampleData.shared.getMessages(count: 1, allowedSenders: [sender]) { (message) in
+                queuedMessage = message.first
+            }
             onTypingStatusCode?()
         }
     }

Example/Sources/Settings+UserDefaults.swift

@@ -41,4 +41,14 @@ extension UserDefaults {
         }
         return 20
     }
+    
+    static func isFirstLaunch() -> Bool {
+        let hasBeenLaunchedBeforeFlag = "hasBeenLaunchedBeforeFlag"
+        let isFirstLaunch = !UserDefaults.standard.bool(forKey: hasBeenLaunchedBeforeFlag)
+        if isFirstLaunch {
+            UserDefaults.standard.set(true, forKey: hasBeenLaunchedBeforeFlag)
+            UserDefaults.standard.synchronize()
+        }
+        return isFirstLaunch
+    }
 }

Example/Sources/View Controllers/SettingsViewController.swift

@@ -30,12 +30,12 @@ final internal class SettingsViewController: UITableViewController {
 
     // MARK: - Properties
     
-    var selectedMockMessagesCount: Int = 20
-    
     override var preferredStatusBarStyle: UIStatusBarStyle {
         return .lightContent
     }
     
+    let cells = ["Mock messages count", "Text Messages", "AttributedText Messages", "Photo Messages", "Video Messages", "Emoji Messages", "Location Messages", "Url Messages", "Phone Messages"]
+    
     // MARK: - Picker
     
     var messagesPicker = UIPickerView()
@@ -55,6 +55,8 @@ final internal class SettingsViewController: UITableViewController {
         messagesPicker.dataSource = self
         messagesPicker.delegate = self
         messagesPicker.backgroundColor = .white
+        
+        messagesPicker.selectRow(UserDefaults.standard.mockMessagesCount(), inComponent: 0, animated: false)
     }
     
     // MARK: - Toolbar
@@ -82,12 +84,25 @@ final internal class SettingsViewController: UITableViewController {
     // MARK: - TableViewDelegate & TableViewDataSource
     
     override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        return 1
+        return cells.count
     }
     
     override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
+        let cellValue = cells[indexPath.row]
+        let cell = tableView.dequeueReusableCell(withIdentifier: "cell") ?? UITableViewCell()
+        cell.textLabel?.text = cells[indexPath.row]
         
-        return indexPath.row == 0 ? configureTextFieldTableViewCell(at: indexPath) : UITableViewCell()
+        switch cellValue {
+        case "Mock messages count":
+            return configureTextFieldTableViewCell(at: indexPath)
+        default:
+            let switchView = UISwitch(frame: .zero)
+            switchView.isOn = UserDefaults.standard.bool(forKey: cellValue)
+            switchView.tag = indexPath.row
+            switchView.addTarget(self, action: #selector(self.switchChanged(_:)), for: .valueChanged)
+            cell.accessoryView = switchView
+        }
+        return cell
     }
     
     override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
@@ -118,6 +133,12 @@ final internal class SettingsViewController: UITableViewController {
         }
         return TextFieldTableViewCell()
     }
+    
+    @objc func switchChanged(_ sender: UISwitch!) {
+        let cell = cells[sender.tag]
+                
+        UserDefaults.standard.set(sender.isOn, forKey: cell)
+    }
 }
 
 // MARK: - UIPickerViewDelegate, UIPickerViewDataSource
@@ -134,8 +155,4 @@ extension SettingsViewController: UIPickerViewDelegate, UIPickerViewDataSource {
     func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
         return "\(row)"
     }
-    
-    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
-        selectedMockMessagesCount = row
-    }
 }

README.md

@@ -90,7 +90,7 @@ github "MessageKit/MessageKit"
 ## Contributing
 
 Great! Look over these things first.
-- Please read our [Code of Conduct](https://github.com/MessageKit/MessageKit/blob/master/Code_of_Conduct.md)
+- Please read our [Code of Conduct](https://github.com/MessageKit/MessageKit/blob/master/CODE_OF_CONDUCT.md)
 - Check the [Contributing Guide Lines](https://github.com/MessageKit/MessageKit/blob/master/CONTRIBUTING.md).
 - Come join us on [Slack](https://join.slack.com/t/messagekit/shared_invite/MjI4NzIzNzMyMzU0LTE1MDMwODIzMDUtYzllYzIyNTU4MA) and 🗣 don't be a stranger. 
 - Check out the [current issues](https://github.com/MessageKit/MessageKit/issues) and see if you can tackle any of those. 

Sources/Controllers/MessagesViewController.swift

@@ -181,6 +181,8 @@ UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
         return collectionView.messagesDataSource?.numberOfItems(inSection: section, in: collectionView) ?? 0
     }
 
+    /// Note:
+    ///   If you override this method, remember to call MessagesDataSource's customCell(for:at:in:) for MessageKind.custom messages, if necessary
     open func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
 
         guard let messagesCollectionView = collectionView as? MessagesCollectionView else {
@@ -207,7 +209,7 @@ UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
             cell.configure(with: message, at: indexPath, and: messagesCollectionView)
             return cell
         case .custom:
-            fatalError(MessageKitError.customDataUnresolvedCell)
+            return messagesDataSource.customCell(for: message, at: indexPath, in: messagesCollectionView)
         }
     }
 

Sources/Layout/MessageSizeCalculator.swift

@@ -132,7 +132,7 @@ open class MessageSizeCalculator: CellSizeCalculator {
 
     // MARK: - Avatar
 
-    public func avatarPosition(for message: MessageType) -> AvatarPosition {
+    open func avatarPosition(for message: MessageType) -> AvatarPosition {
         let dataSource = messagesLayout.messagesDataSource
         let isFromCurrentSender = dataSource.isFromCurrentSender(message: message)
         var position = isFromCurrentSender ? outgoingAvatarPosition : incomingAvatarPosition
@@ -146,7 +146,7 @@ open class MessageSizeCalculator: CellSizeCalculator {
         return position
     }
 
-    public func avatarSize(for message: MessageType) -> CGSize {
+    open func avatarSize(for message: MessageType) -> CGSize {
         let dataSource = messagesLayout.messagesDataSource
         let isFromCurrentSender = dataSource.isFromCurrentSender(message: message)
         return isFromCurrentSender ? outgoingAvatarSize : incomingAvatarSize
@@ -154,14 +154,14 @@ open class MessageSizeCalculator: CellSizeCalculator {
 
     // MARK: - Top cell Label
 
-    public func cellTopLabelSize(for message: MessageType, at indexPath: IndexPath) -> CGSize {
+    open func cellTopLabelSize(for message: MessageType, at indexPath: IndexPath) -> CGSize {
         let layoutDelegate = messagesLayout.messagesLayoutDelegate
         let collectionView = messagesLayout.messagesCollectionView
         let height = layoutDelegate.cellTopLabelHeight(for: message, at: indexPath, in: collectionView)
         return CGSize(width: messagesLayout.itemWidth, height: height)
     }
 
-    public func cellTopLabelAlignment(for message: MessageType) -> LabelAlignment {
+    open func cellTopLabelAlignment(for message: MessageType) -> LabelAlignment {
         let dataSource = messagesLayout.messagesDataSource
         let isFromCurrentSender = dataSource.isFromCurrentSender(message: message)
         return isFromCurrentSender ? outgoingCellTopLabelAlignment : incomingCellTopLabelAlignment
@@ -169,14 +169,14 @@ open class MessageSizeCalculator: CellSizeCalculator {
     
     // MARK: - Top message Label
     
-    public func messageTopLabelSize(for message: MessageType, at indexPath: IndexPath) -> CGSize {
+    open func messageTopLabelSize(for message: MessageType, at indexPath: IndexPath) -> CGSize {
         let layoutDelegate = messagesLayout.messagesLayoutDelegate
         let collectionView = messagesLayout.messagesCollectionView
         let height = layoutDelegate.messageTopLabelHeight(for: message, at: indexPath, in: collectionView)
         return CGSize(width: messagesLayout.itemWidth, height: height)
     }
     
-    public func messageTopLabelAlignment(for message: MessageType) -> LabelAlignment {
+    open func messageTopLabelAlignment(for message: MessageType) -> LabelAlignment {
         let dataSource = messagesLayout.messagesDataSource
         let isFromCurrentSender = dataSource.isFromCurrentSender(message: message)
         return isFromCurrentSender ? outgoingMessageTopLabelAlignment : incomingMessageTopLabelAlignment
@@ -184,14 +184,14 @@ open class MessageSizeCalculator: CellSizeCalculator {
 
     // MARK: - Bottom Label
 
-    public func messageBottomLabelSize(for message: MessageType, at indexPath: IndexPath) -> CGSize {
+    open func messageBottomLabelSize(for message: MessageType, at indexPath: IndexPath) -> CGSize {
         let layoutDelegate = messagesLayout.messagesLayoutDelegate
         let collectionView = messagesLayout.messagesCollectionView
         let height = layoutDelegate.messageBottomLabelHeight(for: message, at: indexPath, in: collectionView)
         return CGSize(width: messagesLayout.itemWidth, height: height)
     }
 
-    public func messageBottomLabelAlignment(for message: MessageType) -> LabelAlignment {
+    open func messageBottomLabelAlignment(for message: MessageType) -> LabelAlignment {
         let dataSource = messagesLayout.messagesDataSource
         let isFromCurrentSender = dataSource.isFromCurrentSender(message: message)
         return isFromCurrentSender ? outgoingMessageBottomLabelAlignment : incomingMessageBottomLabelAlignment
@@ -213,7 +213,7 @@ open class MessageSizeCalculator: CellSizeCalculator {
 
     // MARK: - MessageContainer
 
-    public func messageContainerPadding(for message: MessageType) -> UIEdgeInsets {
+    open func messageContainerPadding(for message: MessageType) -> UIEdgeInsets {
         let dataSource = messagesLayout.messagesDataSource
         let isFromCurrentSender = dataSource.isFromCurrentSender(message: message)
         return isFromCurrentSender ? outgoingMessagePadding : incomingMessagePadding

Sources/Layout/MessagesCollectionViewFlowLayout.swift

@@ -147,6 +147,8 @@ open class MessagesCollectionViewFlowLayout: UICollectionViewFlowLayout {
     lazy open var videoMessageSizeCalculator = MediaMessageSizeCalculator(layout: self)
     lazy open var locationMessageSizeCalculator = LocationMessageSizeCalculator(layout: self)
 
+    /// - Note:
+    ///   If you override this method, remember to call MessageLayoutDelegate's customCellSizeCalculator(for:at:in:) method for MessageKind.custom messages, if necessary
     open func cellSizeCalculatorForItem(at indexPath: IndexPath) -> CellSizeCalculator {
         let message = messagesDataSource.messageForItem(at: indexPath, in: messagesCollectionView)
         switch message.kind {
@@ -163,7 +165,7 @@ open class MessagesCollectionViewFlowLayout: UICollectionViewFlowLayout {
         case .location:
             return locationMessageSizeCalculator
         case .custom:
-            fatalError("Must return a CellSizeCalculator for MessageKind.custom(Any?)")
+            return messagesLayoutDelegate.customCellSizeCalculator(for: message, at: indexPath, in: messagesCollectionView)
         }
     }
 

Sources/Models/MessageKind.swift

@@ -52,9 +52,9 @@ public enum MessageKind {
     case emoji(String)
 
     /// A custom message.
-    /// - Note: Using this case requires that you override the following methods and handle this case:
-    ///   - `collectionView(_:cellForItemAt indexPath: IndexPath) -> UICollectionViewCell`
-    ///   - `cellSizeCalculatorForItem(at indexPath: IndexPath) -> CellSizeCalculator`
+    /// - Note: Using this case requires that you implement the following methods and handle this case:
+    ///   - MessagesDataSource: customCell(for message: MessageType, at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> UICollectionViewCell
+    ///   - MessagesLayoutDelegate: customCellSizeCalculator(for message: MessageType, at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> CellSizeCalculator
     case custom(Any?)
 
     // MARK: - Not supported yet

Sources/Protocols/MessagesDataSource.swift

@@ -92,6 +92,17 @@ public protocol MessagesDataSource: AnyObject {
     ///
     /// The default value returned by this method is `nil`.
     func messageBottomLabelAttributedText(for message: MessageType, at indexPath: IndexPath) -> NSAttributedString?
+    
+    /// Custom collectionView cell for message with `custom` message type.
+    ///
+    /// - Parameters:
+    ///   - message: The `custom` message type
+    ///   - indexPath: The `IndexPath` of the cell.
+    ///   - messagesCollectionView: The `MessagesCollectionView` in which this cell will be displayed.
+    ///
+    /// - Note:
+    ///   This method will call fatalError() on default. You must override this method if you are using MessageType.custom messages.
+    func customCell(for message: MessageType, at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> UICollectionViewCell
 }
 
 public extension MessagesDataSource {
@@ -115,4 +126,8 @@ public extension MessagesDataSource {
     func messageBottomLabelAttributedText(for message: MessageType, at indexPath: IndexPath) -> NSAttributedString? {
         return nil
     }
+    
+    func customCell(for message: MessageType, at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> UICollectionViewCell {
+        fatalError(MessageKitError.customDataUnresolvedCell)
+    }
 }

Sources/Protocols/MessagesLayoutDelegate.swift

@@ -80,6 +80,17 @@ public protocol MessagesLayoutDelegate: AnyObject {
     /// - Note:
     ///   The default value returned by this method is zero.
     func messageBottomLabelHeight(for message: MessageType, at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> CGFloat
+    
+    /// Custom cell size calculator for messages with MessageType.custom.
+    ///
+    /// - Parameters:
+    ///   - message: The custom message
+    ///   - indexPath: The `IndexPath` of the cell.
+    ///   - messagesCollectionView: The `MessagesCollectionView` in which this cell will be displayed.
+    ///
+    /// - Note:
+    ///   The default implementation will throw fatalError(). You must override this method if you are using messages with MessageType.custom.
+    func customCellSizeCalculator(for message: MessageType, at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> CellSizeCalculator
 }
 
 public extension MessagesLayoutDelegate {
@@ -103,4 +114,8 @@ public extension MessagesLayoutDelegate {
     func messageBottomLabelHeight(for message: MessageType, at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> CGFloat {
         return 0
     }
+    
+    func customCellSizeCalculator(for message: MessageType, at indexPath: IndexPath, in messagesCollectionView: MessagesCollectionView) -> CellSizeCalculator {
+        fatalError("Must return a CellSizeCalculator for MessageKind.custom(Any?)")
+    }
 }