> ## 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
> All Real Time Listeners — CometChat documentation.
CometChat provides 4 listeners viz.
1. [UserListener](/sdk/flutter/3.0/resources-all-real-time-listeners#user-listener)
2. [GroupListener](/sdk/flutter/3.0/resources-all-real-time-listeners#group-listener)
3. [MessageListener](/sdk/flutter/3.0/resources-all-real-time-listeners#message-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 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 object received as the parameter. |
To add the `UserListener`, you need to use the `addUserListener()` method provided by the `CometChat` class.
```dart theme={null}
class Class_Name with UserListener {
//CometChat.addUserListener("user_Listener_id", this);
@override
void onUserOnline(User user) {
// TODO: implement onUserOnline
}
@override
void onUserOffline(User user) {
// TODO: implement onUserOffline
}
}
```
where `UNIQUE_LISTENER_ID` is the unique identifier for the listener. Please make sure that no two listeners are added with the same listener id as this could lead to unexpected behaviour resulting in loss of events.
Once the activity/fragment where the `UserListener` is declared is not in use, you need to remove the listener using the `removeUserListener()` method which takes the id of the listener to be removed as the parameter. We suggest you call this method in the `onPause()` method of the activity/fragment.
```dart theme={null}
CometChat.removeUserListener(UNIQUE_LISTENER_ID)
```
## 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. |
To add the `GroupListener`, you need to use the `addGroupListener()` method provided by the `CometChat` class.
```dart theme={null}
class Class_Name with GroupListener {
//CometChat.addGroupListener("UNIQUE_LISTENER_ID", this);
@override
void onGroupMemberJoined(Action action, User joinedUser, Group joinedGroup) {
}
@override
void onGroupMemberLeft(Action action, User leftUser, Group leftGroup) {
}
@override
void onGroupMemberKicked(Action action, User kickedUser, User kickedBy, Group kickedFrom) {
}
@override
void onGroupMemberBanned(Action action, User bannedUser, User bannedBy, Group bannedFrom) {
}
@override
void onGroupMemberUnbanned(Action action, User unbannedUser, User unbannedBy, Group unbannedFrom) {
}
@override
void onGroupMemberScopeChanged(Action action, User updatedBy, User updatedUser, String scopeChangedTo, String scopeChangedFrom, Group group) {
}
@override
void onMemberAddedToGroup(Action action, User addedby, User userAdded, Group addedTo) {
}
}
```
where `UNIQUE_LISTENER_ID` is the unique identifier for the listener. Please make sure that no two listeners are added with the same listener id as this could lead to unexpected behaviour resulting in loss of events.
Once the activity/fragment where the `GroupListener` is declared is not in use, you need to remove the listener using the `removeGroupListener()` method which takes the id of the listener to be removed as the parameter. We suggest you call this method in the `onPause()` method of the activity/fragment.
```dart theme={null}
CometChat.removeGroupListener(UNIQUE_LISTENER_ID)
```
## 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. |
| `onMessageDeleted(BaseMessage message)` | This event is triggered when a particular message is deleted in a user/group conversation. |
To add the `MessageListener`, you need to use the `addMessageListener()` method provided by the `CometChat` class.
```dart theme={null}
class Class_Name with MessageListener {
//CometChat.addMessageListener("listenerId", this);
@override
void onTextMessageReceived(TextMessage textMessage) {
}
@override
void onMediaMessageReceived(MediaMessage mediaMessage) {
}
@override
void onCustomMessageReceived(CustomMessage customMessage) {
}
@override
void onTypingStarted(TypingIndicator typingIndicator) {
}
@override
void onTypingEnded(TypingIndicator typingIndicator) {
}
@override
void onMessagesDelivered(MessageReceipt messageReceipt) {
}
@override
void onMessagesRead(MessageReceipt messageReceipt) {
}
@override
void onMessageEdited(BaseMessage message) {
}
@override
void onMessageDeleted(BaseMessage message) {
}
}
```
where `UNIQUE_LISTENER_ID` is the unique identifier for the listener. Please make sure that no two listeners are added with the same listener id as this could lead to unexpected behaviour resulting in loss of events.
Once the activity/fragment where the `MessageListener` is declared is not in use, you need to remove the listener using the `removeMessageListener()` method which takes the id of the listener to be removed as the parameter. We suggest you call this method in the `onPause()` method of the activity/fragment.