TreeGrid FolderOpenedHandler ... how to sync with dataFetch ?

[kccheng]

Hi,

I have a TreeGrid connect to RestDataSource.
When a folder been clicked, it will fetch the child node data
and expand the node.

And now I want to do something with the child node when the folder expanded ... so I implement the FolderOpenedHandler.

        treeGrid.addFolderOpenedHandler(new FolderOpenedHandler() {
            public void onFolderOpened(FolderOpenedEvent event) {
                TreeNode node = event.getNode();
                TreeNode[] nodes = treeGrid.getData().getChildren(node);
  
                for (int i=0; i<nodes.length; ++i) {
                    // do something ...
                }
            }
        });

My problem is ... when the first time the folder been clicked (opened), the data is still fetching from RestDataSource ... so
the for loop doesn't work.

After the RestDataSource been fetched into TreeGrid, the for loop
work perfectly.

My question is ... how can I wait for dataFetch() ready in
FolderOpenedHandler ?

Thanks
KC