ErrorMessageDiv
The messages an error fence caught, as bare lines: no caption, no frame. It is what a piece of a screen uses to keep its own complaints inside itself.
Div panel = new Div();
cp.add(panel);
ErrorMessageDiv emd = new ErrorMessageDiv(panel); // Makes the panel a fence and listens to it
panel.add(emd);
Making one
| Constructor | What it does |
|---|---|
ErrorMessageDiv(NodeContainer parent) |
makes parent an error fence and registers itself as its listener |
ErrorMessageDiv(NodeContainer parent, boolean propagate) |
the same, but with true the fence also hands what it catches to the fence above it |
ErrorMessageDiv() |
neither; use setAsErrorFence(parent) later, or register it on a component as an external error listener |
The one-argument constructor is two things in one call - the fence and the component that shows what it catches - which is why it is the usual way to give a panel messages of its own. Note that it only registers the div; adding it to the panel is still up to you, and where you add it is where the messages appear.
Propagating is for a message that has to be visible in two places at once: a
panel deep in a page that shows its own errors, on a screen where the page as a
whole also lists everything that is wrong. It is a
PropagatingErrorFenceHandler on the panel; the message is shown here and then
travels on.
What it does with the messages
- It is hidden while empty (
visibility: hidden) and shows itself when a message arrives. - The border class follows the severest message in it (
ui-emd-brd-error,-warning,-info), and each line carries the type of that one message. - An info message makes way for a real one: when a warning or an error arrives, the info messages already on display are dropped. The other way round they are not - an info message never replaces a warning.
- The control a message belongs to gets
ui-input-err, and loses it when the message is removed.
For the block with a caption, and for what the application shows by default, see
ErrorPanel.