ExpandHeader
ExpandHeader is a header that owns what is under it: pressing it folds that
content away, pressing it again brings it back.
ExpandHeader header = new ExpandHeader("Sales history");
cp.add(header);
header.setContent(salesTable);
The API
| Method | What it does |
|---|---|
new ExpandHeader(String title) |
a normal-sized header |
new ExpandHeader(Type, String) |
NORMAL or SMALL |
setContent(NodeBase) |
what the header folds away - give it this, or it has nothing to do |
setExpanded(boolean) / isExpanded() / toggleExpansion() |
open and close from code |
setCaption(String) / setCaptionNode(NodeBase) |
the title, as a text or as a node |
setActionList(List<IUIAction<?>>) / clearActions() |
a hamburger menu of actions at the right |
The difference with the other two headers is exactly that ownership: a
GenericHeader or a
Caption2 is a line above whatever happens to follow it,
while this one is given the content and shows or hides it.
What folding costs
The content node stays on the page and is hidden, so folding is a css change
rather than a rebuild: the state of everything inside it - a half-filled form, a
table's scroll position - survives. It also means the content is built even
while it is closed. Where that is the expensive part, put the content in a
TabPanel tab marked lazy() instead, which is not
built until it is first shown.