Event delegation overview

Nexconn Chat SDK delivers real-time events through handler protocols. Each protocol covers a specific domain — group channels, open channels, messages, users, and so on. You register handlers via NCEngine using a unique identifier string, which lets you add multiple independent listeners for the same event type and remove them individually.

How it works

All handler protocols follow the same three-step pattern:

1. Register — call the addXxxHandler(identifier:handler:) class method on NCEngine before you expect events.
2. Implement — adopt the protocol and implement only the callbacks you care about. All protocol methods are @optional.
3. Remove — call removeXxxHandler(forIdentifier:) when the handler is no longer needed (for example, in viewDidDisappear or deinit).

Swift

swift

import NexconnChatSDK
// Register
NCEngine.addGroupChannelHandler(identifier: "MyHandler", handler: self)
// Remove
NCEngine.removeGroupChannelHandler(forIdentifier: "MyHandler")

Objective-C

Objective C

// Register
[NCEngine addGroupChannelHandlerWithIdentifier:@"MyHandler" handler:self];

// Remove
[NCEngine removeGroupChannelHandlerForIdentifier:@"MyHandler"];

All callbacks deliver an event object. The event object carries all the data relevant to that event. Read the details through its properties rather than through separate parameters.

Swift

swift

import NexconnChatSDK
func onGroupOperation(_ event: GroupOperationEvent) {
    print("Group: \(event.groupId), operation: \(event.operation.rawValue)")
}

Objective-C

Objective C

- (void)onGroupOperation:(NCGroupOperationEvent *)event {
    NSLog(@"Group: %@, operation: %ld", event.groupId, (long)event.operation);
}

Available handler protocols

Protocol	Register/Remove method prefix	What it covers
NCGroupChannelHandler	addGroupChannelHandler	Group operations, profile changes, member changes, join requests
NCOpenChannelHandler	addOpenChannelHandler	Open channel enter/exit lifecycle, metadata, members, mute, ban
NCChannelHandler	addChannelHandler	Channel list sync, pinned/DND/translate settings, typing status, community sub-channel events
NCUserHandler	addUserHandler	Subscription events, friend add/delete/apply/clear
NCUserSettingsHandler	addUserSettingsHandler	User-level settings sync completed
NCMessageHandler	addMessageHandler	Message receive, delete, modify, read receipts, stream messages, metadata
NCTagEventHandler	addTagHandler	Tag and channel-tag changes (multi-device sync)
NCTranslateHandler	addTranslateHandler	Translation language changes and auto-translate state
NCDatabaseStatusHandler	addDatabaseStatusHandler	Database schema upgrade lifecycle
NCConnectionStatusHandler	addConnectionStatusHandler	SDK connection status changes

See the individual pages for full callback details and code examples.