Updating a hierarchical list...

> Hi!
>
> I am developing a hierarchical browser of hetergoenous objects (e.g.
> objects of different classes). I am using an AbstractHiererachicalList
> with a SimpleHierarchicalListMorph. The problem is, that if I add a
> new item into the list, it does not update itself and I must manually
> toggle the tree of the list to see the new item. I found out, that
> calling self list: (self model getList) perfectly updates the whole
> list and keeps the expanded trees expanded. The problem is, that the
> objects inside the list have no reference to the list itself so I
> cannot use the above call. Can anyone help? Is there a default
> mechanism to solve this problem, or it has to be implemented by an
> EventHandler?
>
> Thanks in advance,
>
> Elod
>
>

> Elod Kironsky a écrit :
>
>> Hi!
>>
>> I am developing a hierarchical browser of hetergoenous objects (e.g.
>> objects of different classes). I am using an
>> AbstractHiererachicalList with a SimpleHierarchicalListMorph. The
>> problem is, that if I add a new item into the list, it does not
>> update itself and I must manually toggle the tree of the list to see
>> the new item. I found out, that calling self list: (self model
>> getList) perfectly updates the whole list and keeps the expanded
>> trees expanded. The problem is, that the objects inside the list have
>> no reference to the list itself so I cannot use the above call. Can
>> anyone help? Is there a default mechanism to solve this problem, or
>> it has to be implemented by an EventHandler?
>>
>> Thanks in advance,
>>
>> Elod
>>
>>
> Hi Elod,
>
> AbstractHierarchicalList is the model. It should have a method to
> build the tree and send it to its SimpleHierarchicalListMorph.
> Usually #getList is used and then if you want to refresh the list you
> simply have to send "changed: #getList" to the model.
>
> see #update: method in SimpleHierarchicalListMorph:
> update: aSymbol
>    aSymbol == getSelectionSelector
>        ifTrue: [self selection: self getCurrentSelectionItem.
>            ^ self].
>    aSymbol == getListSelector
>        ifTrue: [self list: self getList.
>            ^ self].
>    ((aSymbol isKindOf: Array)
>            and: [aSymbol notEmpty
>                    and: [aSymbol first == #openPath]])
>        ifTrue: [^ (scroller submorphs
>                at: 1
>                ifAbsent: [^ self])
>                openPath: aSymbol allButFirst]
>
> alain
>
>

> Yes, that is clear to me. The problem is, that the objects inside the
>
> list have no reference to the model (AbstractHierarchicalList), so
> they
> cannot send changed: #getList. Is there a way, that i just fire and
> event or message into the "Squeak world" and every object just gets
> it
> and can react if it wants to?
>
> Elod
>
>
>

>Hi Elod, have you considered the Smalltalk dependency mechanism, the
>more general Listener pattern or even Notifications?
>
>Good luck..
>
>  
>
>>Yes, that is clear to me. The problem is, that the objects inside the
>>
>>list have no reference to the model (AbstractHierarchicalList), so
>>they
>>cannot send changed: #getList. Is there a way, that i just fire and
>>event or message into the "Squeak world" and every object just gets
>>it
>>and can react if it wants to?
>>
>>Elod
>>
>>
>>
>>    
>>
>
>
>
>  
>