ZK Developer's Guide

Getting Started with ZK
After this small example, we will make a second example with an input element
inside. This application consists of one main screen. This screen has a label (Insert
your name), an input field, and a hidden button (Say Hello). The following
screenshot shows the screen.
The definition of this screen is done in a single file. Its name is helloworld.zul. Both
the layout and logic is done in that page. The page is realized with the previously
mentioned ZK User Interface Markup Language.
Now it's time to draw the curtain and show the implementation of this simple
application as follows:
0 && event.getValue().trim()
.length() > 0)
{
buttonToSayHello.setVisible(true);
}
else
{
buttonToSayHello.setVisible(false);
}
]]>