I asked the question in Blackberry support forum and got the answer:
If we follow the documentation, we know that dataModel looks like this:
<root>
<header> ... </header>
<header> ... </header>
<header> ... </header>
</root>
Then we change the rootIndexPath
to the index of the header. So only the child of that header is shown. The index is in array integer type
myListView.rootIndexPath = [0] //Show all child of first header
myListView.rootIndexPath = [1] //Show all child of second header