New Features of ZK 9.5.0

From Documentation
New Features of ZK 9.5.0

Hawk Chen, Engineer, Potix Corporation
Sep. 29, 2020
ZK 9.5.0


ZK is a tool created by developers, for developers. In ZK 9.5 we put our first priority on advancing the DX - Developer Experience - by providing a smoother upgrade path, simplified MVVM syntax and usages, easier theme & component customization, among others.

In addition, a preview version enabling web accessibility support has been released with keyboard navigation, screen reader support, high contrast themes, and other features facilitating WCAG2 compliance.

Enjoy, and we look forward to receiving your feedback.


Highlighted features.png

Web Accessibility Support

  • Available for ZK:
  • ee.png

We are excited to announce a preview version of the za11y (ZK Accessibility) package for WCAG 2 compliance. Various enhancements have been made on ZK components for keyboard interaction (focus, navigation order, …) and screen reader support (aria-labels, roles, …). In addition, accessibility-ready themes are made available for providing sufficient color contrast and focus style.

Check out the ZA11Y Demo and corresponding GitHub Project.

Learn more about ZK Developer's Reference/Accessibility and WCAG themes.


[SPECIAL EVENT] Feedback to ZK WCAG features and win ZK gifts. Learn More >>

Data Binding Syntax Sugar and Simplified Usage

  • Available for ZK:
  • ce-pe-ee.png

ZK now provides a simplified syntax with a built-in convention. Shortened syntax and conventions make it easier to code and speed up your development.

Init ViewModel Shortcut

You can apply a ViewModel on a component in a shorter way. Then, ZK will assign a default ViewModel ID as vm without having to explicitly specify it. Also you no longer need to specify "init".

<!-- original syntax -->
<div viewModel="@id('vm') @init('MyViewModel')" >

<!-- shortcut syntax -->
<div viewModel="@('MyViewModel')">

Implicit Init Binding

Now you can apply an init property binding without specifying "init".

<!-- original syntax -->
<label value="@init(vm.greeting)"/>

<!-- shortcut syntax -->
<label value="@(vm.greeting)"/>

For other bindings e.g. @load, @bind, you have to specify them explicitly.

Implicit Command Binding

Now ZK will create a command binding at an event attribute (starting with on) by default. Yo don't need to specify command explicitly.

<!-- original syntax -->
<button onClick="@command('hello')"/>

<!-- shortcut syntax -->
<button onClick="@('hello')"/>

Besides, no need to apply @Command on a command method.

    // original usage
    public void hello(){

    // simplified usage
    public void hello(){

Command Binding Parameter Inference

The original syntax

public void pick(@BindingParam("checked") boolean isPicked, 
                 @BindingParam("picked")Item item){...}
<checkbox onCheck="@command('pick', checked=self.checked, picked=each)">

The shortcut syntax

Now you can declare a command method without @BindingParam and passing parameters to that command method without specifying a key. ZK will pass each parameter according to its order. So you need to make the parameter order consistent between zul and the method.

public void pick( boolean isPicked, Item item){...}
<checkbox onCheck="@('pick',self.checked, each)">

For running examples, please check MVVM example project.

Command Binding to Another ViewModel

Sometimes it's convenient to call a command in another ViewModel of the same desktop.

    <nodom viewModel="@id('vm')@init('org.zkoss.mvvm.databinding.CommandVM')">
        <button label="hello" onClick="@('hello')"/>
    <nodom viewModel="@id('vmInit')@init('org.zkoss.mvvm.databinding.InitVM')">
        <button label="call the previous VM" onClick="@('$vm.hello')"/>
  • Line 6: Need to append $ on a ViewModel ID, so it's $vm.

Bean Creation When Passing Parameters

Assume there is a Java bean:

public class Item {

	private int id;
	private String name;

//getter and setter

The Previous Usage

Pass parameters with key-value pairs in a command binding.

<button label="create" onClick="@('create', id=idbox.value, name=namebox.value)"/>

List all parameters in a command method signature:

public void create(@BindingParam("id")int id, @BindingParam("name")String name){...}

New Usage

We still need to specify the parameter key in a command binding. But now we can just declare the Java bean in a command method, then ZK will new the bean and set the bean's value with the command binding's parameter.

    public void create(@BindingParams Item item){

Notify Change Shortcut Method

The Previous Method Call

BindUtils.postNotifyChange(null, null, this, "value1");

The 1st and 2nd parameter (queue name and queue scope) are null in most cases. Therefore, ZK provides a shortcut method below.

New Method Call

BindUtils.postNotifyChange(this, "value1");

Theme Template Supports Compact Themes

  • Available for ZK:
  • ce-pe-ee.png

ZK Theme Template provides an easy way for theme customization. It is now updated to support compact themes — you can now customize a compact theme (e.g. iceblue_c) as easy as the standard themes, and upgrade the theme easily (continuous/incremental compile) when you upgrade your ZK version.


Radio/Checkbox Status CSS Class

  • Available for ZK:
  • ce-pe-ee.png

CSS classes for different status are now applied to Radio/Checkbox. This makes it much easier to custom style for different states.



Popup: Specify A Different Reference Component

  • Available for ZK:
  • ce-pe-ee.png

With previous versions, when you associate a popup to a component, that component is always taken as the reference component to show the popup. Since ZK 9.5 you can specify another component as the reference component with ref=component-id.

For example, you can associate a popup to a button while showing a popup at a textbox:

    <textbox id="address" placeholder="target address" style="margin-bottom: 30px; display:block"/>
    <button label="show more" popup="pp, ref=address, position=end_after"/>

    <popup id="pp">
        more info

For other popup options, please refer to ZK Component Reference/Essential Components/Popup

Searchbox Easy Clear

  • Available for ZK:
  • ee.png

Searchbox now has an x icon. After you select an item, if you wish to remove the current selected item, you can now press DELETE or click the x icon to do so.

Backward Compatibility: ZK 7 Form Binding

  • Available for ZK:
  • ce-pe-ee.png

In ZK 8, a new MVVM form binding was introduced for better efficiency and more features. However, it also made it difficult for ZK 7 projects to upgrade. In ZK 9.5 we have now ported back ZK 7’s simple form binding. If you have ZK 7 projects that use the legacy simple form binding, you can easily upgrade to ZK 9.5 with minimum code changes.

Notification Styles Updated

  • Available for ZK:
  • ce-pe-ee.png

The Notification style for Iceblue, Iceblue_c, and ThemePack Themes are updated to a modern look and feel while providing a better contrast level for WCAG compliance.

New style since 9.5.0

Zk95-info.jpg Zk95-warn.jpg Zk95-error.jpg

Zk95-dark-info.jpg Zk95-dark-warn.jpg Zk95-dark-error.jpg

Style used in 9.1.0 and older versions

Zk91-info.jpg Zk91-warn.jpg Zk91-error.jpg


Introducing fetch( ) API for Redirection/SSO handling

  • Available for ZK:
  • ce-pe-ee.png

Redirect (HTTP 302) including SSO handling has always been a common challenge in Ajax. In 9.5, javascript fetch( ) API is used instead of XHR allowing better redirect handling.

Client API supports scrollIntoView and focus using selector

  • Available for ZK:
  • ce-pe-ee.png

With this new feature, developers can now focus (or scrollIntoView) a component specified by selector syntax with Java API, and a browser will focus the corresponding DOM element:


Clients.scrollIntoView("#mywind textbox");

These 2 methods don't require a component reference as a parameter, so invoking them doesn't break the MVVM pattern. For more examples, please see zkbooks > mvvmreference >

Listbox Enhancements

Listbox is one of the most commonly used components. It is complicated in the way that it provides a table view with selection, frozen, paging, ROD, auto-sizing and many custom attributes. In ZK 9.5 we have made several enhancements to cover a wider range of use cases.

  • Fixed listbox sizing issue with "rows" attribute
  • Listbox model now supports an array of class
  • Fixed broken ROD popup & JS error during partial invalidate
  • Refined the selection behavior when part of the items are selected

iPadOS13+ Support

  • Available for ZK:
  • ce-pe-ee.png

Apple has changed the implementation and now an iPadOS13+ device no longer identifies itself with the iOS Safari User Agent (UA) string, but with the MacOS Safari one instead. Corresponding changes have been made in ZK 9.5 to ensure ZK detects the devices correctly.

Upgrade Notes

Upgrade notes.png

  • Since 9.5.0, the transitive dependency of slf4j-jdk14 was removed. Please specify your preferred logger instead.
  • Since 9.5.0, the transitive dependency of closure-compiler-unshaded was removed. If you wish to enable source maps, please include it manually.
  • zAu.onError API was changed since fetch() API is now used instead of XHR.
  • Due to ZK-4622, the DIV of grid/listbox/tree header border is removed. You may need to adjust the styles accordingly.


Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.