ZK Developer's Guide

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Chapter 4
With the doOverlapped method, we get the ability to move the window around.
However, when we click on add testdata to add some data to the main listbox, we
enforce a reload of the page because of Executions.sendRedirect("index.zul")
at the end of the action of add testdata. After reload, the position of rememberWindow
is lost. To solve this problem, we have to store the position of the window component
in the session, and restore that position in the construction phase of the window. To
implement this feature, we have to extend org.zkoss.zul.Window.
public class RememberWindow extends Window implements EventListener
{
/******************************************************************
********
* Internal Constants
*******************************************************************
*******/
private final static String LEFT = "LEFT";
private final static String TOP = "TOP";
/******************************************************************
********
* Instance variables
*******************************************************************
*******/
private boolean setBySession = false;
private String firstTop;
private String firstLeft;
/******************************************************************
********/
/**
* Constructor.
* A event listener for the event onMove is registered.
*/
public RememberWindow()
{
this.addEventListener("onMove", this);
// Restore the left position from the session if avaiable
if (Sessions.getCurrent().getAttribute(LEFT) != null)
{
this.setLeft((String) Sessions.getCurrent().getAttribute(LEFT));
this.setBySession = true;
}
// Restore the top position from the session if avaiable
if (Sessions.getCurrent().getAttribute(TOP) != null)
{
this.setTop((String) Sessions.getCurrent().getAttribute(TOP));
}