Enable and disable the whiteboard

The whiteboard module in Flexible Classroom is implemented based on AgoraWidget. You can turn the whiteboard module on or off in the classroom by setting the widget state as active or inactive.

After disabling the whiteboard module, drawing tools including pencil, text box, shape, and eraser will no longer be available and users cannot upload, delete, or display class files on the whiteboard. Other features that do not rely on the whiteboard, such as uploading or deleting class files, pop-up quiz, count-down timer, and screen sharing will not be affected.

The component corresponding to the Whiteboard widget is named AgoraEduWhiteBoardComponent, and the widget ID can be obtained using AgoraWidgetDefaultId.WhiteBoard.id. Use this component to turn the Whiteboard on or off.

To enable or disable the Whiteboard, you monitor the status changes of the Whiteboard caused by the teacher client and adjust the UI accordingly. See initView() in the file AgoraEduUIKit/src/main/java/com/agora/edu/component/whiteboard/AgoraEduWhiteBoardComponent.kt for the logic of registering observers, listening for active states, and creating or destroying Whiteboard components in the methods.

If you want to open and close the Whiteboard by yourself, you can refer to the following code examples:

• To turn on the Whiteboard, add the following code to the file where the button to open the Whiteboard is located:

  
  

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  val info = AgoraWidgetRoomPropsUpdateReq(state = 1)

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  eduContext?.widgetContext()?.setWidgetActive(AgoraWidgetDefaultId.WhiteBoard.id, info)

  
  

• To close the Whiteboard, add the following code to the file where the button to close the Whiteboard is located:

  
  

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  eduContext?.widgetContext()?.setWidgetInActive(AgoraWidgetDefaultId.WhiteBoard.id)

  
  

• To register an observer, use the following code:

  
  

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  eduContext?.widgetContext()?.addWidgetActiveObserver(widgetActiveObserver, AgoraWidgetDefaultId.LargeWindow.id)

  
  

• To monitor the status of the widget, use the following code:

  
  

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  private val widgetActiveObserver = object : AgoraWidgetActiveObserver {

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  override fun onWidgetActive(widgetId: String) {

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  // The Whiteboard has been created, here is the child thread

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  if (widgetId == AgoraWidgetDefaultId.WhiteBoard.id) {

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  }

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  }

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  override fun onWidgetInActive(widgetId: String) {

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  // The Whiteboard has been removed, here is the child thread

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  if (widgetId == AgoraWidgetDefaultId.WhiteBoard.id) {

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  }

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  }

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  }

  
  

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fun create(config: AgoraWidgetConfig): AgoraBaseWidget?

Create a Widget object instance.

Parameter:

• config: The configuration information of this Widget object.

Return: Widget instance, empty means creation failed.

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fun getWidgetConfig(widgetId: String): AgoraWidgetConfig?

Get the configuration information of a registered Widget.

Parameter:

• widgetId: The unique identifier of the Widget.

Return: An AgoraWidgetConfig object.

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fun setWidgetActive(widgetId: String, ownerUserUuid: String? = null,

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roomProperties: Map<String, Any>? = null,

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callback: EduContextCallback<Unit>? = null)

Activate a Widget.

Parameter:

• widgetId: Widget's unique identifier.
• ownerUserUuid: UserUuid of the user who owns the currently activated Widget.
• roomProperties: Initialized room properties.
• callback: Callback listener for activation operation.

Return: After the operation is successful, you will receive the callback of AgoraWidgetActiveObserver.onWidgetActive

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fun setWidgetInActive(widgetId: String, isRemove: Boolean = false, callback: EduContextCallback<Unit>? = null)

Unregister the specified Widget.

Parameter:

• widgetId: Widget's unique identifier.
• isRemove: Whether to completely delete all information of this Widget in the current classroom:
  • true: Delete completely. All information under roomProperties.widgets.'widgetId' and userProperties.widgets.'widgetId' will be removed.
  • false: Only set roomProperties.widgets.'widgetId'.state to '0', that is, set the current Widget as inactive. No matter what this value is passed, it will receive the callback of AgoraWidgetActiveObserver.onWidgetInActive.
• callback: Callback listener for logout operation.

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fun getWidgetActive(widgetId: String): Boolean

Get the activation state of a Widget.

Parameter:

• widgetId: Widget's unique identifier.

Return: Boolean indicating the activation state of a Widget.

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fun getAllWidgetActive(): Map<String, Boolean>

Get the activation status of all registered Widgets.

Return: Map holding the activation statuses of all registered Widgets.

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fun addWidgetActiveObserver(observer: AgoraWidgetActiveObserver, widgetId: String)

Add an AgoraWidgetActiveObserver listener to monitor whether this Widget is active.

Parameter:

• observer: AgoraWidgetActiveObserver listener to add.
• widgetId: Widget's unique identifier.

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fun removeWidgetActiveObserver(observer: AgoraWidgetActiveObserver, widgetId: String)

Delete an AgoraWidgetActiveObserver listener.

Parameter:

• observer: AgoraWidgetActiveObserver listener to remove.
• widgetId: Widget's unique identifier.

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fun addWidgetMessageObserver(observer: AgoraWidgetMessageObserver, widgetId: String)

Add an AgoraWidgetMessageObserver listener to listen to all messages sent by this Widget.

Parameter:

• observer: AgoraWidgetMessageObserver listener to add.
• widgetId: Widget's unique identifier.

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fun removeWidgetMessageObserver(observer: AgoraWidgetMessageObserver, widgetId: String)

Delete an AgoraWidgetMessageObserver listener.

Parameter:

• observer: AgoraWidgetMessageObserver listener to remove.
• widgetId: Widget's unique identifier.

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fun sendMessageToWidget(msg: String, widgetId: String)

Send a message to a Widget.

Parameter:

• msg: Message to send.
• widgetId: Widget's unique identifier.