如何将根项目添加到SWT树

Question

This is the sample code I'm using to create a Tree ( t ) in a TreeViewer ( viewer ), where MasterTreeContentProvider is a class that implements ITreeContentProvider .

Tree t = toolkit.createTree(client, SWT.NULL);
GridData gd = new GridData(GridData.FILL_BOTH);
gd.heightHint = 20;
gd.widthHint = 100;
t.setLayoutData(gd);
toolkit.paintBordersFor(client);
section.setClient(client);
final SectionPart spart = new SectionPart(section);
managedForm.addPart(spart);
viewer = new TreeViewer(t);
viewer.addSelectionChangedListener(new ISelectionChangedListener() 
{
    public void selectionChanged(SelectionChangedEvent event) 
    {
        managedForm.fireSelectionChanged(spart, event.getSelection());
    }
});
viewer.setContentProvider(new MasterTreeContentProvider());
viewer.setInput(page.getEditor().getEditorInput()); 

Inside the MasterTreeContentProvider class I defined getElements() in such a way that it gets the contents (say Child1, Child2, Child3 ).

With the present code it gets displayed in the following way:

Child1
Child2
Child3

and I would like to look the tree in this way, with the Root as below:

Root
|-- Child1
 -- Child2
 -- Child3

How and where do I add a root element to this tree?

Answer 1

It is not enough to implement getElements() in your MasterTreeContentProvider . You have to implement getChildren() to build the hierarchy you want to show. The Object you pass to those methods should be a custom class which represents this hierarchy. See Eclipse JFace Tree - Tutorial for a good example.