Hi Ben,

I think that hard-linking the collections inside the drop block isn't working in that case, so you have to write that without any reference to collection1 and collection2 :)

But, since you're here: why don't I have an API to add or remove items from the ListModel instance? If I was working in VisualWorks, I would have used one of the model subclasses for collections and I would have used its API for adding or removing items... Here writing code like:

list1
acceptDropBlock: [ :transfer :event :source :receiver :index |
| c1 c2 l1 l2 |
l1 := source model model.
               l2 := transfer source model model.
               transfer passenger do: [ :e |
               l1 insert: e first before: index.
                l2 remove: e first ] ].

i.e. have the ListModel instance behave as a collection for a subset of the usual collection api.

Thierry

Le 04/04/2014 00:40, Benjamin Van Ryseghem a �crit :

here is a "hackish" solution:

        collection1 := #(1 2 3 4 5) asOrderedCollection.
        collection2 := #($a $b $c $d $e) asOrderedCollection.
        list1 := ListModel new.
        list1 items: collection1.
        list1 dragEnabled: true.
        list1 dropEnabled: true.
         list1
                acceptDropBlock: [ :transfer :event :source :receiver
:index |
                        | c1 c2 l1 l2 |
                        l1 := source model model.
                        c1 := l1 listItems.
                        l2 := transfer source model model.
                        c2 := l2 listItems.
                        transfer passenger
                                do: [ :e |
                                        c1 insert: e first before: index.
                                        c2 remove: e first ].
                        l1 items: c1.
collection1 removeAll; addAll: c1.
                        l2 items: c2.
collection2 removeAll; addAll: c2. ].
        list1 openWithSpec.
        list2 := ListModel new.
        list2 items: collection2.
        list2 dragEnabled: true.
        list2 dropEnabled: true.
        list2 acceptDropBlock: [ :transfer :event :source :receiver
:index |
self halt ].
        ^ list2 openWithSpec.

The problem here is that by default, the list items are sorted, setting
the listItems with a copy.
Maybe it would be better to actually do not sort until one sets a real
sortingBlock.

Ben


2014-04-03 22:55 GMT+02:00 MartinW <wm@fastmail.fm <mailto:wm@fastmail.fm>>:

   Goubier Thierry wrote
    > Another approach, that I would use, is to put more complex objects
    > inside the lists. Thoses objects would know how to get added /
   removed
    > from their respective collections, and then I would propagate
   collection
    > changes to the ListModel instances.

   That sounded promising. I made a Collectible class. It's instances
   know how
   to add themselves to a collection (i'm not sure if that's a good
   idea, but
   as experiment..)

   The problem is, i never get to these objects in my acceptDropBlock. In

   list1 acceptDropBlock: [ :transfer :event :source :receiver :index |
       transfer passenger do: [:element | element addSelfToCollection:
   collection1] ].

   the element is only a ByteString - the name of my Collectible object. :(

   Are there other possibilities if i do not use Spec?



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