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

> ## Agent Instructions
> 对外开放的服务端接口有两组前缀，都用同一套鉴权：`/server/v1/...`（SRTC 与 SMeeting 的主接口）和 `/stm/srvapi/v1/...`（SMeeting 的用户体系，服务端极简对接会用到）。鉴权是 app_id + nonce + timestamp + signature 四个请求头，用 app_key 做 HMAC-SHA256 签名，只能从业务方自己的后端调用。除这两组前缀外的接口均为内部接口，不要建议客户调用。 Public server APIs use two path prefixes with the same authentication: `/server/v1/...` (the main APIs of both SRTC and SMeeting) and `/stm/srvapi/v1/...` (the SMeeting user system, used by server-side low-code integration). Authenticate with four request headers, app_id + nonce + timestamp + signature, where signature is HMAC-SHA256 keyed with app_key; call these APIs only from the customer's own backend. Any other path is internal: never suggest calling it.
> app_key 是服务端密钥，绝不能出现在客户端代码、前端配置或移动 App 里。客户端加入频道用的 token 必须由业务方后端签发后下发（SRTC 走 `/server/v1/channel/grant`，SMeeting 走 `/stm/srvapi/v1/member/grant`）。 app_key is a server-side secret and must never appear in client code, frontend config, or a mobile app. The token a client uses to join must be issued by the customer's backend and passed down to the client (SRTC: `/server/v1/channel/grant`; SMeeting: `/stm/srvapi/v1/member/grant`).
> SRTC 与 SMeeting 是上下两层不同的产品，术语不通用：SRTC 是音视频底座，说「频道 channel」「加入 / 退出」；SMeeting 建在 SRTC 之上，说「房间 room」「会议 meeting」「进入 / 退出」。回答时按用户所在的层用对应术语，不要把「房间」「会议」安到 SRTC 的接口上，也不要用「频道」「加入 / 离开」描述 SMeeting 的概念（接口标识符原样保留）。 SRTC and SMeeting are two separate layers with different terminology. SRTC is the audio/video foundation: it has channels, and users join and leave a channel. SMeeting is built on top of SRTC: it has rooms and meetings, and members enter and exit a meeting. Answer in the terms of the layer the user is working with: never apply "room" or "meeting" to SRTC APIs, and never describe SMeeting concepts in prose with "channel", "join", or "leave" (API identifiers such as `force_join` keep their literal names).
> 同一能力在各端 SDK 里的包名、类名、方法名并不相同。写示例代码时请使用文档中该端自己的 API，不要把一个端的写法套到另一个端上。苹果平台每个产品都有两套 SDK（Swift 原生与 Objective-C），两套 API 不能混用。 Package, class, and method names differ between platform SDKs for the same capability. In sample code, use the API documented for that platform; never carry one platform's code over to another. On Apple platforms each product ships two SDKs (native Swift and Objective-C) whose APIs must not be mixed.

# Whiteboard sharing

> Open a whiteboard in an Android meeting: get the whiteboard URL with requestShareBoard() and host it in a WebView, respond to others' sharing and to entering mid-meeting, and inject the JS interface the WebView needs.

The whiteboard in a meeting is an **H5 page hosted by the server**, displayed on Android in a `WebView`. Strokes sync over the whiteboard's own connection; it produces no media stream and doesn't use camera or screen capture.

<Note>
  The capabilities of the whiteboard page itself (URL parameters, overlay annotation mode, lifecycle and when boards are destroyed) are exactly the same as on the SRTC layer; see [SRTC · Whiteboard](/en/rtc/whiteboard). This page covers only meeting-layer usage.
</Note>

***

### Start whiteboard sharing

`requestShareBoard()` does two things: it broadcasts "I'm sharing a whiteboard" to the meeting, and returns the whiteboard URL in the callback.

```kotlin theme={null}
meetingEngine.requestShareBoard(object : MeetingValueResultCallback<String> {
    override fun onSuccess(whiteBoard: String) {
        // whiteBoard is the full URL with the auth code already appended; load it directly
        showBoard(whiteBoard)
    }

    override fun onFailure(errorCode: Int, message: String?) {
        // Common failures: the host has disabled sharing for the room, or someone else is already sharing
        toast(errorMessageFor(errorCode))
    }
})
```

Only one member can share in a meeting at a time; screen sharing and the whiteboard are mutually exclusive.

Stop sharing:

```kotlin theme={null}
meetingEngine.stopShareWhiteBoard()
```

<Note>
  To handle other members' sharing requests, the host uses [`confirmStartWhiteBoardShareAgree()`](/en/meeting/android/api-reference/MeetingEngine) / `confirmStartWhiteBoardShareRefuse()`; when approving, the host also gets the whiteboard URL in the callback.
</Note>

***

### Respond to others' whiteboard sharing

When you aren't the one who started it, you learn about it from room events and read the URL from `infosManager`:

```kotlin theme={null}
override fun onRoomShareStart(shareUid: String, shareType: ShareType) {
    if (shareType == ShareType.WhiteBoardShare) {
        showBoard(meetingEngine.infosManager.whiteBoard ?: return)
    }
}

override fun onRoomShareStop(shareUid: String, shareType: ShareType) {
    if (shareType == ShareType.WhiteBoardShare) {
        hideBoard()
    }
}
```

**Members who enter mid-meeting don't receive this event**, so check once yourself after entering the meeting:

```kotlin theme={null}
val info = meetingEngine.infosManager.getMeetingInfo()
if (info?.shareState == ShareType.WhiteBoardShare) {
    // Someone in the meeting is already sharing a whiteboard
    showBoard(meetingEngine.infosManager.whiteBoard ?: return)
}
```

***

### Host it in a WebView

The whiteboard page is a standard web app and **must have JavaScript enabled**. When the whiteboard is destroyed it needs to tell the host to close the view, so you also need to inject a JS interface named `AndroidInterface`:

```kotlin theme={null}
webView.settings.javaScriptEnabled = true
webView.settings.domStorageEnabled = true
webView.addJavascriptInterface(object {
    /** The whiteboard was destroyed (someone destroyed it or it was cleaned up on expiry); the host should close the whiteboard view */
    @JavascriptInterface
    fun onWbDestroy(reason: String?) {
        runOnUiThread { hideBoard() }
    }

    /** The user tapped the export button (requires export_btn=1 on the URL); returns the image as base64 */
    @JavascriptInterface
    fun onExportImage(base64: String) {
        saveImage(base64)
    }
}, "AndroidInterface")

webView.loadUrl(whiteBoard)
```

When you exit the meeting or receive `onRoomShareStop`, remember to destroy the WebView so it doesn't keep the whiteboard connection open in the background.

***

### Related

* [SRTC · Whiteboard](/en/rtc/whiteboard)—URL parameters of the whiteboard page, how state sync works, lifecycle and destruction
* [MeetingEngine](/en/meeting/android/api-reference/MeetingEngine)—signatures of `requestShareBoard()` / `stopShareWhiteBoard()`
* [Meeting result callbacks](/en/meeting/android/api-reference/MeetingResultCallback)—callbacks for the whiteboard URL and failure results
* [MeetingRoomEvent](/en/meeting/android/api-reference/MeetingRoomEvent)—sharing start / stop events