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Drag & drop in parent - child relation [message #1760572]

Fri, 28 April 2017 13:36

Thomas Oberle

Messages: 11
Registered: April 2017

Junior Member

Hi everybody,

I am trying to implement drag & drop functionality to my GEF4 application.

I have parent nodes (SWComponent) and child nodes (SWFunction). SWFunctions can be added to SWComponents.

Drag & drop works fine if I implement it for SWComponentPart or SWFunctionPart only. Therefore I use:

adapterMapBinder.addBinding(AdapterKey.defaultRole()).to(FXTransformPolicy.class);
adapterMapBinder.addBinding(AdapterKey.defaultRole()).to(FXTranslateSelectedOnDragPolicy.class);

But If I implement it for both SWComponent and SWFunction I get a lot of errors if I try to drag a SWFunction within a SWComponent.
(Draging a SWFunction or SWComponent within RootPart still works)

The first Error occures in AbstractTransactionPolicy -> checkUninitialized() and says "Already initialized"
I suppose this happens because I bind FXTransformPolicy to both SWComponentPart and SWFunctionPart?
Is this not allowed?
What do I have to do to enable drag and drop for SWFunctions within SWComponents while SWComponents can still be dragged.

Thanks,
Thomas

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Re: Drag & drop in parent - child relation [message #1760595 is a reply to message #1760572]

Fri, 28 April 2017 17:49

Alexander Nyssen

Messages: 244
Registered: July 2009
Location: Lünen

Senior Member

You will need to replace the default ITargetPolicyResoler (GEF4) resp. IHandlerResolver (GEF 5.0) with a custom implementation that prevents that both parts are drag targets.

Your resolver will probably have to only resolve the function part as target when its located inside a component part (and exclude the component part).

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