public interface ILazyTreeContentProvider extends IContentProvider
Modifier and Type | Method and Description |
---|---|
Object |
getParent(Object element)
Returns the parent for the given element, or
null
indicating that the parent can't be computed. |
void |
updateChildCount(Object element,
int currentChildCount)
Called when the TreeViewer needs an up-to-date child count for the given
element, for example from
StructuredViewer.refresh() and
StructuredViewer.setInput(Object) . |
void |
updateElement(Object parent,
int index)
Called when a previously-blank item becomes visible in the TreeViewer.
|
dispose, inputChanged
void updateElement(Object parent, int index)
TreeViewer.replace(Object, int, Object)
. The content provider
should also update the child count for any replaced element by calling
TreeViewer.setChildCount(Object, int)
. If the given current child
count is already correct, setChildCount does not have to be called since
a call to replace will not change the child count. If the content
provider doesn't know the child count at this point, and can more
efficiently determine if the element has any children, then it can
instead call TreeViewer.setHasChildren(Object, boolean)
.
NOTE #updateElement(int index) can be used to determine selection values. If TableViewer#replace(Object, int) is not called before returning from this method, selections may have missing or stale elements. In this situation it is suggested that the selection is asked for again after replace() has been called.
parent
- The parent of the element, or the viewer's input if the
element to update is a root elementindex
- The index of the element to update in the treevoid updateChildCount(Object element, int currentChildCount)
StructuredViewer.refresh()
and
StructuredViewer.setInput(Object)
. If the content provider knows the
given element, it should respond by calling
TreeViewer.setChildCount(Object, int)
. If the given current
child count is already correct, no action has to be taken by this content
provider.element
- The element for which an up-to-date child count is needed, or
the viewer's input if the number of root elements is requestedcurrentChildCount
- The current child count for the element that needs updatingObject getParent(Object element)
null
indicating that the parent can't be computed.
In this case the tree-structured viewer can't expand
a given node correctly if requested.element
- the elementnull
if it
has none or if the parent cannot be computed
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