How to obeserver a built in panel

To add an observer to any existing panel you should have following approach:

1. Find the panel widget boss from the respective ID file.

In your case it is kMediaPanelWidgetBoss in MediaUIID.h

2. Add your observer on the boss in the boss definition (fr) as follows:

AddIn

{

    kMediaPanelWidgetBoss,

    kErasablePrimaryResourcePanelWidgetBoss,

    {

        IID_IMYOBSERVER, IMyObserverImpl,

    }

}

3. Provide implementation for IMyObserverImpl by inheriting required partial impl.

For example, if I want to observe on the widgets.

Class MyObserver : public CWidgetObserver

Implement AutoAttach, AutoDetach, and Update methods.

void AutoAttach() {

    InterfacePtr<IPanelControlData> panelData ( this, IID_IPANELCONTROLDATA );

    AttachToWidget(kPlayLoopCheckBoxWidgetID, IID_ITRISTATECONTROLDATA, IID_IOBSERVER, panelData);

}

Update(const ClassID& theChange, ISubject* theSubject, const PMIID &protocol, void* changedBy) {

  InterfacePtr<IControlView> controlView(theSubject, UseDefaultIID());

  WidgetID widgetID = controlView->GetWidgetID();

    switch( widgetID.Get() )

    {

        case kPlayLoopCheckBoxWidgetID:

        {

          // your code

        }

    }

}

Some of the widget IDs in the media panel are:

kPlaceMediaButtonWidgetID

kPlayLoopCheckBoxWidgetID

kPlaceVideoFromURLPanelWidgetID

kPosterDropDownListWidgetID

kControllerDropDownListWidgetID

kShowPreviewButtonWidgetID