> ## Documentation Index
> Fetch the complete documentation index at: https://www.cometchat.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Message Structure and Hierarchy

> Understand CometChat Android SDK message categories, message types, base messages, and message hierarchy for chat apps.

<Accordion title="AI Integration Quick Reference">
  **Message Categories:**

  * **Message**: text, image, video, audio, file
  * **Custom**: Developer-defined types (e.g., location)
  * **Interactive**: form, card, customInteractive
  * **Action**: groupMember, message (system-generated)
  * **Call**: audio, video (with status: initiated, ongoing, ended, etc.)

  **Check message type:**

  ```kotlin theme={null}
  when (message.category) {
      CometChatConstants.CATEGORY_MESSAGE -> { /* Handle message */ }
      CometChatConstants.CATEGORY_CUSTOM -> { /* Handle custom */ }
      CometChatConstants.CATEGORY_ACTION -> { /* Handle action */ }
      CometChatConstants.CATEGORY_CALL -> { /* Handle call */ }
  }
  ```
</Accordion>

Every message in CometChat belongs to a category and has a specific type within that category. Understanding this hierarchy helps you handle different message types correctly.

## Message Hierarchy

<Frame>
  <img src="https://mintcdn.com/cometchat-22654f5b/dDWpooIQ48haNjyU/images/76f2cb7e-bvoxc4srq8tenc66v5dsah0sxmup8mbhqae59irsfboesbs98fexfs1ouqvw6218-b163973e26cc92682c683dfc90dbd452.png?fit=max&auto=format&n=dDWpooIQ48haNjyU&q=85&s=78753cb64971efe8929449ccf564a29b" width="5474" height="3406" data-path="images/76f2cb7e-bvoxc4srq8tenc66v5dsah0sxmup8mbhqae59irsfboesbs98fexfs1ouqvw6218-b163973e26cc92682c683dfc90dbd452.png" />
</Frame>

## Categories Overview

| Category      | Types                                     | Description                          |
| ------------- | ----------------------------------------- | ------------------------------------ |
| `message`     | `text`, `image`, `video`, `audio`, `file` | Standard user messages               |
| `custom`      | Developer-defined                         | Custom data (location, polls, etc.)  |
| `interactive` | `form`, `card`, `customInteractive`       | Messages with actionable UI elements |
| `action`      | `groupMember`, `message`                  | System-generated events              |
| `call`        | `audio`, `video`                          | Call-related messages                |

## Checking Message Category and Type

Use `getCategory()` and `getType()` on a [`BaseMessage`](/sdk/reference/messages#basemessage) to determine how to handle a received message:

<Tabs>
  <Tab title="Java">
    ```java theme={null}
    String category = message.getCategory();
    String type = message.getType();

    switch (category) {
        case CometChatConstants.CATEGORY_MESSAGE:
            if (type.equals(CometChatConstants.MESSAGE_TYPE_TEXT)) {
                TextMessage textMsg = (TextMessage) message;
                Log.d(TAG, "Text: " + textMsg.getText());
            } else if (type.equals(CometChatConstants.MESSAGE_TYPE_IMAGE)) {
                MediaMessage mediaMsg = (MediaMessage) message;
                Log.d(TAG, "Image URL: " + mediaMsg.getAttachment().getFileUrl());
            }
            break;
        case CometChatConstants.CATEGORY_CUSTOM:
            CustomMessage customMsg = (CustomMessage) message;
            Log.d(TAG, "Custom type: " + type + ", data: " + customMsg.getCustomData());
            break;
        case CometChatConstants.CATEGORY_ACTION:
            Action actionMsg = (Action) message;
            Log.d(TAG, "Action: " + actionMsg.getAction());
            break;
        case CometChatConstants.CATEGORY_CALL:
            Call callMsg = (Call) message;
            Log.d(TAG, "Call status: " + callMsg.getCallStatus());
            break;
    }
    ```
  </Tab>

  <Tab title="Kotlin">
    ```kotlin theme={null}
    val category = message.category
    val type = message.type

    when (category) {
        CometChatConstants.CATEGORY_MESSAGE -> {
            if (type == CometChatConstants.MESSAGE_TYPE_TEXT) {
                val textMsg = message as TextMessage
                Log.d(TAG, "Text: ${textMsg.text}")
            } else if (type == CometChatConstants.MESSAGE_TYPE_IMAGE) {
                val mediaMsg = message as MediaMessage
                Log.d(TAG, "Image URL: ${mediaMsg.attachment?.fileUrl}")
            }
        }
        CometChatConstants.CATEGORY_CUSTOM -> {
            val customMsg = message as CustomMessage
            Log.d(TAG, "Custom type: $type, data: ${customMsg.customData}")
        }
        CometChatConstants.CATEGORY_ACTION -> {
            val actionMsg = message as Action
            Log.d(TAG, "Action: ${actionMsg.action}")
        }
        CometChatConstants.CATEGORY_CALL -> {
            val callMsg = message as Call
            Log.d(TAG, "Call status: ${callMsg.callStatus}")
        }
    }
    ```
  </Tab>
</Tabs>

## Message

Standard user messages. Types: `text`, `image`, `video`, `audio`, `file`.

## Custom

Developer-defined messages for content that doesn't fit standard categories (e.g., location sharing, polls). Set your own `type` string to identify the custom message.

## Interactive

Messages with embedded UI elements users can interact with directly in chat.

Types: `form`, `card`, `customInteractive`.

<Note>
  See [Interactive Messages](/sdk/android/interactive-messages) for full details.
</Note>

## Action

System-generated messages triggered by actions on group members or messages. Represented as [`Action`](/sdk/reference/messages#action) objects.

Types: `groupMember`, `message`.

The `action` property specifies what happened:

**For `groupMember`:** `joined`, `left`, `kicked`, `banned`, `unbanned`, `added`, `scopeChanged`

**For `message`:** `edited`, `deleted`

## Call

Call-related messages. Types: `audio`, `video`. Represented as [`Call`](/sdk/reference/messages#call) objects.

The `status` property indicates the call state: `initiated`, `ongoing`, `canceled`, `rejected`, `unanswered`, `busy`, `ended`.

***

## Next Steps

<CardGroup cols={2}>
  <Card title="Send Message" icon="paper-plane" href="/sdk/android/send-message">
    Send text, media, and custom messages
  </Card>

  <Card title="Receive Messages" icon="envelope" href="/sdk/android/receive-messages">
    Handle incoming messages of all types
  </Card>

  <Card title="Additional Message Filtering" icon="filter" href="/sdk/android/additional-message-filtering">
    Filter messages by category, type, and other parameters
  </Card>

  <Card title="Interactive Messages" icon="square-check" href="/sdk/android/interactive-messages">
    Create and handle interactive form and card messages
  </Card>
</CardGroup>