JSF checkbox listener

Question

I have a checkbox and a button on my JSF page. I want the button

Answer 1

What is the JSF way of doing this with no javascript and no listener method on my java class

This is plain impossible. I gather that you actually meant, "no manually written JavaScript" (and thus you accept JSF-generated JavaScript as used by <f:ajax>) and "no manually written listener method" (and thus you accept JSF own magic on the component tree state).

In that case, this should do:

<h:form>
    <h:selectBooleanCheckbox binding="#{checkbox}">
        <f:ajax render="button" />
    </h:selectBooleanCheckbox>
    <h:commandButton id="button" value="submit" 
        action="#{bean.submit}" 
        disabled="#{not checkbox.value}" />
</h:form>

That's all. No additional JS code nor JSF bean properties or listener methods needed. Just a submit() action method.

The binding attribute will in this example put the UIComponent reference of <h:selectBooleanCheckbox> in the Facelet scope under the variable name checkbox. The EL expression #{checkbox.value} returns the value attribute of the component which represents in case of an UISelectBoolean component already a boolean, ready for use in command component's disabled attribute.

Note: if you're facing an incorrect EL error at the line disabled="#{not checkbox.value}" in an older Eclipse version, then you'd need to configure it as follows: Window > Preferences > Web > JavaServer Faces Tools > Validation > Type Coercion Problems > Unary operation boolean coercion problems set it to Warning or Ignore instead of Error. This is not necessary anymore since Eclipse Mars.

See also:

• How does the 'binding' attribute work in JSF? When and how should it be used?

Answer 2

You need to this by calling a valueChangeListener on ajax call so you can enable/disable button
Here is checkboxes and button

       <h:selectBooleanCheckbox id="deactivate" title="select to deactivate" 
valueChangeListener="#{bean.myChangeListener}" onchange="submit()">

        <h:selectManyCheckbox value="#{user.favNumber1}">
            <f:selectItem itemValue="1" itemLabel="Number1 - 1" />
            <f:selectItem itemValue="2" itemLabel="Number1 - 2" />
            <f:selectItem itemValue="3" itemLabel="Number1 - 3" />
            <f:ajax event="change" execute="@this" render="dummyButton"/>
        </h:selectManyCheckbox>
    <h:commandButton id="dummyButton" value="OK" render="#{renderBean.myButton}">

You need create a render class with just one attribute whose value will be set in listener method i-e bean#myChangeListener

public class RenderBean{

    boolean myButton;
    public RendeBean(){

            myButton = true;

    }

    public void enableButton(){

          myButton = true;
    }

    public void disableButton(){

          myButton = false;
    }
}

And here is your bean#myChangeListener

public void myChangeListener(ValueChangeEvent e){
     RenderBean rb = (RenderBean) FacesContext.getCurrentInstance()
            .getExternalContext().getSessionMap().get("renderBean");
        if(e.getNewValue().toString().equals("1"))
                     rb.enableButton();
        else
                     rb.disableButton();
}