> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-22654f5b-docs-angular-v5-docs-update.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# All Real-Time Listeners
> Register and manage real-time event listeners for users, groups, messages, and calls in the Android SDK
```kotlin theme={null}
// User listener
CometChat.addUserListener("LISTENER_ID", object : CometChat.UserListener() {
override fun onUserOnline(user: User) { }
override fun onUserOffline(user: User) { }
})
// Message listener
CometChat.addMessageListener("LISTENER_ID", object : CometChat.MessageListener() {
override fun onTextMessageReceived(message: TextMessage) { }
override fun onMediaMessageReceived(message: MediaMessage) { }
})
// Remove listeners (important!)
CometChat.removeUserListener("LISTENER_ID")
CometChat.removeMessageListener("LISTENER_ID")
```
CometChat provides 4 listeners viz.
1. [UserListener](#user-listener)
2. [GroupListener](#group-listener)
3. [MessageListener](#message-listener)
4. [CallListener](#call-listener)
## User Listener
The `UserListener` class provides you with live events related to users. Below are the callback methods provided by the `UserListener` class.
| Method | Information |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `onUserOnline(User user)` | This method is triggered when a user comes online and is available to chat. The details of the user can be obtained from the [`User`](/sdk/reference/entities#user) object received as the method parameter. |
| `onUserOffline(User user)` | This method is triggered when a user goes offline. The details of the user can be obtained from the [`User`](/sdk/reference/entities#user) object received as the parameter. |
Use `addUserListener()` to register and `removeUserListener()` to unregister. Call remove in `onPause()`.
```java theme={null}
CometChat.addUserListener(UNIQUE_LISTENER_ID, new CometChat.UserListener() {
@Override
public void onUserOnline(User user) {
}
@Override
public void onUserOffline(User user) {
}
});
```
```kotlin theme={null}
CometChat.addUserListener(UNIQUE_LISTENER_ID, object : CometChat.UserListener() {
override fun onUserOnline(user: User) {
}
override fun onUserOffline(user: User) {
}
})
```
Always remove listeners when they're no longer needed (e.g., in `onDestroy()` or when navigating away). Failing to remove listeners can cause memory leaks and duplicate event handling.
## Group Listener
The `GroupListener` class provides you with all the real-time events related to groups. Below are the callback methods provided by the `GroupListener` class.
| Method | Information |
| ----------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- |
| `onGroupMemberJoined(Action action, User joinedUser, Group joinedGroup)` | This method is triggered when a user joins any group. All the members present in the group will receive this event. |
| `onGroupMemberLeft(Action action, User leftUser, Group leftGroup)` | This method is triggered when a user who was a member of any group leaves the group. All the members of the group receive this event. |
| `onGroupMemberKicked(Action action, User kickedUser, User kickedBy, Group kickedFrom)` | This method is triggered when a user is kicked from a group. All the members including the user receive this event |
| `onGroupMemberBanned(Action action, User bannedUser, User bannedBy, Group bannedFrom)` | This method is triggered when a user is banned from a group. All the members including the user receive this event |
| `onGroupMemberUnbanned(Action action, User unbannedUser, User unbannedBy, Group unbannedFrom)` | This method is triggered when a user is banned from a group. All the members of the group receive this event. |
| `onGroupMemberScopeChanged(Action action, User updatedBy, User updatedUser, String scopeChangedTo, String scopeChangedFrom, Group group)` | This method is triggered when the scope of any Group Member has been changed. All the members that are a part of that group receive this event |
| `onMemberAddedToGroup(Action action, User addedby, User userAdded, Group addedTo)` | This method is triggered when a user is added to any group. All the members including the user himself receive this event. |
These callbacks use [`Action`](/sdk/reference/messages#action), [`User`](/sdk/reference/entities#user), and [`Group`](/sdk/reference/entities#group) objects.
Use `addGroupListener()` to register and `removeGroupListener()` to unregister. Call remove in `onPause()`.
```java theme={null}
CometChat.addGroupListener("UNIQUE_ID", new CometChat.GroupListener() {
@Override
public void onGroupMemberJoined(Action action, User joinedUser, Group joinedGroup) {
}
@Override
public void onGroupMemberLeft(Action action, User leftUser, Group leftGroup) {
}
@Override
public void onGroupMemberKicked(Action action, User kickedUser, User kickedBy, Group kickedFrom) {
}
@Override
public void onGroupMemberBanned(Action action, User bannedUser, User bannedBy, Group bannedFrom) {
}
@Override
public void onGroupMemberUnbanned(Action action, User unbannedUser, User unbannedBy, Group unbannedFrom) {
}
@Override
public void onGroupMemberScopeChanged(Action action, User updatedBy, User updatedUser, String scopeChangedTo, String scopeChangedFrom, Group group) {
}
@Override
public void onMemberAddedToGroup(Action action, User addedby, User userAdded, Group addedTo) {
}
});
```
```kotlin theme={null}
CometChat.addGroupListener("UNIQUE_ID", object : CometChat.GroupListener() {
override fun onGroupMemberJoined(action: Action, joinedUser: User, joinedGroup: Group) {
}
override fun onGroupMemberLeft(action: Action, leftUser: User, leftGroup: Group) {
}
override fun onGroupMemberKicked(action: Action, kickedUser: User, kickedBy: User, kickedFrom: Group) {
}
override fun onGroupMemberBanned(action: Action, bannedUser: User, bannedBy: User, bannedFrom: Group) {
}
override fun onGroupMemberUnbanned(action: Action, unbannedUser: User, unbannedBy: User, unbannedFrom: Group) {
}
override fun onGroupMemberScopeChanged(action: Action, updatedBy: User, updatedUser: User, scopeChangedTo: String, scopeChangedFrom: String, group: Group) {
}
override fun onMemberAddedToGroup(action: Action, addedby: User, userAdded: User, addedTo: Group) {
}
})
```
## Message Listener
The `MessageListener` class provides you with live events related to messages. Below are the callback methods provided by the `MessageListener` class.
| Method | Information |
| --------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `onTextMessageReceived(TextMessage message)` | This event is triggered when a Text Message is received. |
| `onMediaMessageReceived(MediaMessage message)` | This event is triggered when a Media Message is received. |
| `onCustomMessageReceived(CustomMessage message)` | This event is triggered when a Custom Message is received. |
| `onTypingStarted(TypingIndicator typingIndicator)` | This event is triggered when a user starts typing in a user/group conversation |
| `onTypingEnded(TypingIndicator typingIndicator)` | This event is triggered when a user stops typing in a user/group conversation. |
| `onMessagesDelivered(MessageReceipt messageReceipt)` | This event is triggered when a set of messages are marked as delivered for any particular conversation. |
| `onMessagesRead(MessageReceipt messageReceipt)` | This event is triggered when a set of messages are marked as read for any particular conversation. |
| `onMessageEdited(BaseMessage message)` | This method is triggered when a particular message has been edited in a user/group conversation. See [`BaseMessage`](/sdk/reference/messages#basemessage). |
| `onMessageDeleted(BaseMessage message)` | This event is triggered when a particular message is deleted in a user/group conversation. |
| `onInteractiveMessageReceived(InteractiveMessage message)` | This event is triggered when an Interactive Message is received. |
| `onInteractionGoalCompleted(InteractionReceipt receipt)` | This event is triggered when an interaction Goal is achieved. |
| `onTransientMessageReceived(TransientMessage transientMessage)` | This event is triggered when a Transient Message is received. |
| `onMessageReactionAdded(ReactionEvent reactionEvent)` | This event is triggered when a reaction is added to a message in a user/group conversation. |
| `onMessageReactionRemoved(ReactionEvent reactionEvent)` | This event is triggered when a reaction is remove from a message in a user/group conversation. |
Use `addMessageListener()` to register and `removeMessageListener()` to unregister. Call remove in `onPause()`.
```java theme={null}
CometChat.addMessageListener(UNIQUE_LISTENER_ID, new CometChat.MessageListener() {
@Override
public void onTextMessageReceived(TextMessage message) {
}
@Override
public void onMediaMessageReceived(MediaMessage message) {
}
@Override
public void onCustomMessageReceived(CustomMessage message) {
}
@Override
public void onTypingStarted(TypingIndicator typingIndicator) {
}
@Override
public void onTypingEnded(TypingIndicator typingIndicator) {
}
@Override
public void onMessagesDelivered(MessageReceipt messageReceipt) {
}
@Override
public void onMessagesRead(MessageReceipt messageReceipt) {
}
@Override
public void onMessageEdited(BaseMessage message) {
}
@Override
public void onMessageDeleted(BaseMessage message) {
}
@Override
public void onInteractiveMessageReceived(InteractiveMessage interactiveMessage) {
}
@Override
public void onInteractionGoalCompleted(InteractionReceipt interactionReceipt) {
}
@Override
public void onTransientMessageReceived(TransientMessage transientMessage) {
}
@Override
public void onMessageReactionAdded(ReactionEvent reactionEvent) {
}
@Override
public void onMessageReactionRemoved(ReactionEvent reactionEvent) {
}
});
```
```kotlin theme={null}
CometChat.addMessageListener(UNIQUE_LISTENER_ID, object : CometChat.MessageListener() {
override fun onTextMessageReceived(message: TextMessage) {
}
override fun onMediaMessageReceived(message: MediaMessage) {
}
override fun onCustomMessageReceived(message: CustomMessage) {
}
override fun onTypingStarted(typingIndicator: TypingIndicator) {
}
override fun onTypingEnded(typingIndicator: TypingIndicator) {
}
override fun onMessagesDelivered(messageReceipt: MessageReceipt) {
}
override fun onMessagesRead(messageReceipt: MessageReceipt) {
}
override fun onMessageEdited(message: BaseMessage) {
}
override fun onMessageDeleted(message: BaseMessage) {
}
override fun onInteractiveMessageReceived(interactiveMessage: InteractiveMessage) {
}
override fun onInteractionGoalCompleted(interactionReceipt: InteractionReceipt) {
}
override fun onTransientMessageReceived(transientMessage: TransientMessage) {
}
override fun onMessageReactionAdded(reactionEvent: ReactionEvent) {
}
override fun onMessageReactionRemoved(reactionEvent: ReactionEvent) {
}
})
```
## Call Listener
The `CallListener` class provides you with live events related to calls. Below are the callback methods provided by the `CallListener` class.
| Method | Information |
| ------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `onIncomingCallReceived(Call call)` | This event is triggered when the logged-in user receives an incoming call. The details of the call can be obtained from the [`Call`](/sdk/reference/messages#call) object received as the method parameter. |
| `onOutgoingCallAccepted(Call call)` | This event is triggered when the call initiated by the logged-in user is accepted by the recipient. The details of the call can be obtained from the [`Call`](/sdk/reference/messages#call) object received as the method parameter. |
| `onOutgoingCallRejected(Call call)` | This event is triggered when the call initiated by the logged-in user is rejected by the recipient. The details of the call can be obtained from the [`Call`](/sdk/reference/messages#call) object received as the method parameter |
| `onIncomingCallCancelled(Call call)` | This event is triggered when an incoming call is canceled by the initiator of the call. The details of the call can be obtained from the [`Call`](/sdk/reference/messages#call) object received as the method parameter |
Use `addCallListener()` to register and `removeCallListener()` to unregister. Call remove in `onPause()`.
```java theme={null}
CometChat.addCallListener(UNIQUE_LISTENER_ID, new CometChat.CallListener() {
@Override
public void onIncomingCallReceived(Call call) {
}
@Override
public void onOutgoingCallAccepted(Call call) {
}
@Override
public void onOutgoingCallRejected(Call call) {
}
@Override
public void onIncomingCallCancelled(Call call) {
}
});
```
```kotlin theme={null}
CometChat.addCallListener(UNIQUE_LISTENER_ID, object : CometChat.CallListener() {
override fun onIncomingCallReceived(call: Call) {
}
override fun onOutgoingCallAccepted(call: Call) {
}
override fun onOutgoingCallRejected(call: Call) {
}
override fun onIncomingCallCancelled(call: Call) {
}
})
```
***
## Next Steps
Handle incoming messages with message listeners
Track user online/offline status with user listeners
Handle incoming calls with call listeners
Monitor group events with group listeners