Hi John,

I missed the information about the meaning of TreeViewModel#isLeaf(). I ran
into problem with it yesterday.

Thanks
Rodrigue

On Thu, Nov 4, 2010 at 3:27 PM, John LaBanca <[email protected]> wrote:

> You have two options, but first its important to point out that "leaf" is
> not the same as "empty".  If you have a folder that may or may not have
> children, TreeViewModel#isLeaf() should return false, meaning that the node
> is not a leaf.  When the user opens thenode, one of the following can
> happen.
>
>    - You return a DataProvider with some data, in which case the children
>    are rendered
>    - You return a DataProvider without data, in which case the node
>    "opens", but a message is displayed that the node is empty
>    - You return a null NodeInfo, in which case the node is treated as a
>    leaf
>
> In the second option, you can still push data (such as the first child) to
> the node, and it will render them.  For example, if you return an empty
> ListDataProvider, then add items to the underlying list, the nodes will show
> up.  If you use the other two options, you need to rerender the parent nodes
> so that the Tree will call TreeViewModel#isLeaf() again.
>
> There is no correct answer; its just a matter of user interaction.  You can
> consider a folder to be a leaf, in which case it cannot be opened (no open
> icon).  Or, you can consider a folder to be a non-leaf even if it is empty.
>  Note that at the moment, the "no data" message is fixed, but we can
> probably make that a Cell so you could add a button such as "Create New
> Folder".
>
> Thanks,
> John LaBanca
> [email protected]
>
>
>
> On Thu, Nov 4, 2010 at 3:51 AM, Ståle Undheim <[email protected]> wrote:
>
>> I am using the new GWT 2.1 CellTree to display a list of folders. From
>> the UI I support adding child folders to a folder in the tree. The
>> problem is, I don't know how to fire events or update the tree so that
>> if I add a child to a leaf node, it's converted to a non-leaf node.
>>
>> Do I need to refresh the data on the parent of the node that got a
>> child added?
>>
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