Question

I have a Flex panel, in InDesign, from which I drag an URL. If I drop this URL on a text editor or a web browser, it works. But when I try to drop it on my InDesign document, it’s a little bit harder.

I have implemented a subclass of CDragDropTargetFlavorHelper. The drop works perfectly on Windows. But on mac, I have problems in the method CouldAcceptTypes :

DragDrop::TargetResponse AutocatDNDCustomFlavorHelper::CouldAcceptTypes(const  DragDropTarget* target, DataObjectIterator* dataIter, const IDragDropSource* fromSource,  const IDragDropController* controller) const
{
    if (0 != dataIter && 0 != target)
    {

        DataExchangeResponse response = dataIter->FlavorExistsWithPriorityInAllObjects(kURLDExternalFlavor);
        if (response.CanDo())
        {
            ...
        }
    }
}

The problem is that response.canDo() answers kTrue on Windows, but kFalse on Mac. I tried to explore the content of dataIter, but a call on dataIter->First() returns nil. I tried a controller->GetItemCount(), which returns 1. But if I try a controller->GetDragItem(1), I get a nil pointer. I have the impress there is no item. Though, the drop works on another app than InDesign, as I said.

Is it a problem of internalization ? Or something else ? It let me dry.

Thanks in advance

————————– EDIT ———————————–
I solved this problem, but discovered another one. The flavor sent by the flex panel has been changed, so that it’s a text flavor instead of an URL flavor. My method couldAcceptType works now :

DragDrop::TargetResponse AutocatDNDCustomFlavorHelper::CouldAcceptTypes(const DragDropTarget* target, DataObjectIterator* dataIter, const IDragDropSource* fromSource, const IDragDropController* controller) const
{
    if (0 != dataIter && 0 != target)
    {
        // Check for URL Flavor in the drag
        DataExchangeResponse response = dataIter->FlavorExistsWithPriorityInAllObjects(kTEXTExternalFlavor);
        if (response.CanDo())
            {
                return DragDrop::TargetResponse(response, DragDrop::kDropWillCopy);
            }
    }
    return DragDrop::kWontAcceptTargetResponse;
}

The problem is now in the ProcessDragDropCommand method. Here is the code :

ErrorCode AutocatDNDCustomFlavorHelper::ProcessDragDropCommand(IDragDropTarget* target, IDragDropController* controller, DragDrop::eCommandType action)
{
    // retrieve drop data
    IPMDataObject* dragDataObject = controller->GetDragItem(1);
    uint32 dataSize = dragDataObject->GetSizeOfFlavorData(kTEXTExternalFlavor) ;
    ...
}

The problem is the IMPDataObject I get is nil. There is no item in the controller. However, there were items in the CouldAcceptTypes method, in the DataObjectIterator. So, where are my items ?

I tried using a custom CDataExchangeHandlerFor, but could not really understand what its usage was for. It didn’t work anyway.

Has anyone an idea ?

Regards,
Rémi

Answer 1

The problem is the argument of the GetDragItem. It is 1 on PC. It is a strange value on Mac (something like 719853). The only dirty solution I found is doing a memcpy from the object retrieved drom the dataIter in the CouldAcceptTypes method, and use it in the ProcessDragDropCommand method.