How can I programmatically expand items in a TreeViewer?

Asked Nov 20 '13 at 15:37

Active Nov 20 '13 at 15:50

Viewed 773 times

I have a TreeViewer with an ILazyTreeContentProvider. I want to control the expansion of the top-level tree items: Initially they are unexpanded, but when an Action "Expand" is selected, the item should be expanded.

In the action.run() I currently do

final EntityTreeNode projectNode = (EntityTreeNode) ((ITreeSelection) 
    viewer.getSelection()).getFirstElement();
// notify the content provider that the node should be expanded; it creates child nodes 
// and updates the child count and calls viewer.setChildCount
((LazyEntityModelViewContentProvider) viewer.getContentProvider()).expandProject(projectNode);
viewer.expandToLevel(projectNode, 2);                   
viewer.refresh(projectNode);

But the node is not expanded. It should at least change it's icon to show that it has children...

edited Nov 20 '13 at 15:50

asked Nov 20 '13 at 15:37

Martin Schröder

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Try using a `TreePath` for the `expandToLevel` parameter rather than `projectNode`, it may help the viewer locate the node. – greg-449 Nov 20 '13 at 15:53
@greg-449: `viewer.expandToLevel( ((ITreeSelection) viewer.getSelection()).getPathsFor(projectNode)[0], 255);` does nothing. – Martin Schröder Nov 20 '13 at 16:03
I am talking about `org.eclipse.jface.viewers.TreePath` which you construct with a array of nodes from the root to the node. – greg-449 Nov 20 '13 at 16:11
@greg-449: `ITreeSelection.getPathsFor` returns that. – Martin Schröder Nov 20 '13 at 16:17

How can I programmatically expand items in a TreeViewer?

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