Is there a way how to trigger an event / make a commandbutton hide when selectCheckboxMenu in primefaces unselected all items

Question

i wanted to know if theres a way how to hide a commandbutton to the end users when he deselects all items in the selectCheckboxMenu.

thanks for every comments and suggestions.

Answer 1

For command button set rendered attribute for ex

In managed bean create a boolean variable allCheckBoxNotSelected with getters and setters

For checkboxes in valueChangeListener attribute call a managed bean method which will check current values for all check box. If it is not selected then put false to allCheckBoxNotSelected variable and then upadate command button through its id.

Answer 2

Just let the rendered attribute of the command button check if the very same property behind the value attribute of select checkbox menu does not represent an empty collection. You can re-execute this check by updating a persistent parent component of the button using <p:ajax> on change of the select checkbox menu.

So, in a nutshell:

<p:selectCheckboxMenu value="#{bean.selectedItems}">
    <f:selectItems value="#{bean.availableItems}" />
    <p:ajax update="button" />
</p:selectCheckboxMenu>

<h:panelGroup id="button">
    <p:commandButton value="Submit" rendered="#{not empty bean.selectedItems}" />
</h:panelGroup>

No need for unnecessary code such as additional bean properties or listener methods specifically for value change and rendered attribute or ugly hacks such as valueChangeListener as mentioned by the other answer whose answerer is apparently having JSF 1.x in mind.