Get the user viewing this element.

Throws an exception if no viewer has been set.

Test if a viewer has been set on this element.

Deprecated, use setViewer().

Deprecated, use getViewer().

Test if this View accepts children.

By default, views accept children, but subclases may override this method to prevent children from being appended. Doing so will cause appendChild() to throw exceptions instead of appending children.

Append a child to the list of children.

This method will only work if the view supports children, which is determined by canAppendChild().

Produce children for rendering.

Historically, this method reduced children to a string representation, but it no longer does.

Test if an element has no children.

Reduce effectively-empty lists of children to be actually empty. This recursively removes null, '', and array() from the list of children so that hasChildren() can more effectively align with expectations.

Inconsistent, unreliable pre-rendering hook.

This hook may fire before views render. It is not fired reliably, and may fire multiple times.

If it does fire, views might use it to register data for later loads, but almost no datasources support this now; this is currently only useful for tokenizers. This mechanism might eventually see wider support or might be removed.