ZK Developer's Reference/UI Patterns/Useful Java Utilities

In this section we introduce some of the most commonly used Java utility classes.

Executions

org.zkoss.zk.ui.Executions

getCurrent

Executions.getCurrent()

Retrieves the current execution (request/response).

createComponents

Executions.createComponents()

Creates components defined in another zul file and attaches them to the current page.

sendRedirect

Executions.sendRedirect()

Redirects to another URL. If the parameter is left null, it will redirect to the current page.

 

Sessions

org.zkoss.zk.ui.Sessions

getCurrent

Sessions.getCurrent()

Retrieves the current session.

 

Clients

org.zkoss.zk.ui.util.Clients

This class offers a collection of methods which manipulate client side via AU Response.

evalJavaScript

Clients.evalJavaScript()

This method sends an AU Response to execute the given JavaScript on client side, which is the standard way of calling JavaScript from server side in ZK. For example,

Clients.evalJavaScript("zk.log('Hi.');");

Since 9.6.0 To handle javascript errors triggered by evalJavascript, org.zkoss.zk.ui.ScriptErrorListener.class is provided.

focus

Since 9.5.0 Clients.focus(Component component)

Clients.focus(String selector)

Focus the given component or the selector matched component.

scrollIntoView

Clients.scrollIntoView(Component cmp)

Scrolls the parent of the given component, so the given one becomes visible in the view.

Since 9.5.0

Clients.scrollIntoView(String selector)

Scrolls the parent of the selector matched component, so the given one becomes visible in the view.

Show Busy Message / Block Users Interaction

Clients.showBusy() / Clients.clearBusy()

Display/dismiss a busy message which can cover a component or the whole page. So you can block all interaction to components and let users know the operation is in progress or has finished. For example,

Clients.showBusy(window, "Waiting for server...");

showNotification

Since 6.0.1 Clients.showNotification() Since 9.0.0 It is advised to use Notification class which was introduced in ZK 9 instead.

Shows a notification box, which is dismissed upon left click (like a Popup). You can either display a global notification (bigger) or a notification specific to another component (smaller with an arrow pointing to the target component).

Clients.showNotification(msg); // display a global notification box
Clients.showNotification(msg, component); // display a notification box pointing to a component

You can also specify its position, style, and duration (for auto-dismiss):

Clients.showNotification(msg, type, component, position, duration);

Type determines the style of the notification box.

Here are the available positions:

Closable

Since 6.5.0 Notification now supports closable to let users close the notification box manually.

// add close icon on the top right corner of notification box
Clients.showNotification(msg, closable);

Multiline

To show a multiline message, just append <br/> in the message string.

Clients.showNotification("msg1 <br/> msg2 <br/>");

Notification

Since 9.0.0

org.zkoss.zk.ui.util.Notification

This class offers a collection of methods showing a notification box, which is dismissed upon left click (like a Popup). You can either display a global notification (bigger) or a smaller notification specific to another component (smaller with an arrow pointing to the target component).

Notification.show(msg); // display a global notification box
Notification.show(msg, component); // display a notification box pointing to a component

Toast

• Available for ZK:
• 

Since 9.0.0

org.zkoss.zkmax.ui.util.Toast

This class offers a collection of methods showing a toast notification, which is dismissed upon left click (like a Popup). Unlike Notification, Toast is stackable.

Toast.show(msg); // display a toast notification
Toast.show(msg, "warning", "top_right"); // display a toast notification on top-right of the browser viewport

You can also specify its position, style, duration (for auto-dismiss) and closable:

Toast.show(msg, type, position, duration, closable);

Here are the available positions:

	left	center	right
top	top_left	top_center	top_right
middle	middle_left	middle_center	middle_right
bottom	bottom_left	bottom_center	bottom_right

Animation Speed

To specify the duration of opening and closing animation, org.zkoss.zkmax.ui.util.Toast.animationSpeed is provided.

<library-property>
	<name>org.zkoss.zkmax.ui.util.Toast.animationSpeed</name>
	<value>500</value>
</library-property>

Loadingbar

• Available for ZK:
• 

Since 9.0.0

org.zkoss.zkmax.ui.util.Loadingbar

A Loadingbar behaves like a Progressmeter that provides information on the progress of a task.

You can control a loadingbar with the LoadingbarControl.

// create a LoadingbarControl for control the loadingbar
LoadingbarControl loadingbarCtrl = Loadingbar.createLoadingbar("myId"); 
loadingbarCtrl.start();
loadingbarCtrl.update(20); // update the value to 20
loadingbarCtrl.finish();

You can also specify its value(0~100), position(top/bottom) and indeterminate(true/false):

loadingbarCtrl.start(20, "top", false);

You can turn on/off the indeterminate animation:

loadingbarCtrl.update(true); // set loadingbar indeterminate true

Animation Speed

To specify the Loadingbar animation speed, org.zkoss.zkmax.ui.util.Loadingbar.animationSpeed is provided.

<library-property>
	<name>org.zkoss.zkmax.ui.util.Loadingbar.animationSpeed</name>
	<value>500</value>
</library-property>

Version History

Version	Date	Content
6.0.1	March 2012	Add Clients.showNotification()
6.5.0	July 2012	ZK-1145: Notification supports closable
9.0.0	Sep 2019	ZK-4371: Provide a Toast utility
9.0.0	Sep 2019	ZK-4372: Extract Notification functionalities from Clients
9.0.0	Nov 2019	ZK-4379: Provide a Loadingbar utility
9.5.0	Sep 2020	ZK-4624: Clients API support scrollIntoView and focus by using selector string