I have an input textbox that accept a name, process the name in reverse order, and then output it to another textbox. Whenever I input the value and click anywhere on the page (means lost focus from textbox), the output textbox will get update automatically.
When I open up the source code I found something like code below, may I know what does the ajax thing do to the inputtext component?
<h:inputText id="name" value="#{helloBean.name}">
<f:ajax render="printMyName"/>
</h:inputText>
<h:outputText id="printMyName" value="#{helloBean.reverseName}"/>
Taken from Learning JSF2: Ajax in JSF – using f:ajax tag
Sending an Ajax request
JSF comes with one tag to send an Ajax request, the tag is called
f:ajax. This tag is actually a client side behavior. Being a behavior
implies it’s never just used by itself on a page, it is always added
as a child tag (behavior) to another UI component (or can even wrap
several components). Let’s use a small echo application to demonstrate
usage of this tag.
<h:form>
<h:panelGrid>
<h:inputText value="#{bean.text}" >
<f:ajax event="keyup" render="text"/>
</h:inputText>
<h:outputText id="text" value="#{bean.text}" />
</h:panelGrid>
</h:form>
Code snippet above takes care of firing an Ajax request based on onkeyup event. Notice the actual event name is keyup. This takes care of firing an Ajax request. Next we need to figure out how to do partial view rendering.
Attribute Description event:
String on which event Ajax request will be
fired. If not specified, a default behavior based on parent component
will be applied. The default event is action for ActionSource (ie:
button) components and valueChange for EditableValueHolder components
(ie: input). action and valueChange are actual String values that can
be applied applied event attribute.
Related
https://www.primefaces.org/showcase/ui/ajax/event.xhtml
I want do that same what in showcase but without refreshing page. Like: setting value in inputtext and click on button to view result, but if i have <p:ajax event="blur" />or <p:ajax/> then i must click two times on the button
<p:inputText id="data" value="#{buttonView.data}">
<p:ajax/>
</p:inputText>
<p:commandButton value="Ajax Submit" id="ajax" actionListener="#{buttonView.buttonAction}" />
Maybe something like use outpupanel and update that panel in commandbutton?
If you are to use the <p:commandButton /> then the form will be submitted. In this case use update attribute of <p:commandButton /> to update the target component.
If you want to update another component as soon as you type then use <p:ajax event="keyup" update="your_target_component_id" /> to update your target component. (YOur event can be keyup, keypress, change, blur, etc.)
I don't understand why are you mixing the concept of using p:ajax with the functionality of the p:commandButton.
Basically, usage of p:ajax is intended to partially process the
field(s) value and update the component(s) of the form even without
submitting it.
Example:
You have Countries and States drop-downs (pre-populated) on a screen (let's say registration) with some other fields, but if user changes the country, you need to refill the States drop-down and update on the screen asynchronously. There you need to use the p:ajax.
On the other hand, p:commandButton is intended to submit the form
(not to update the components initially). However, it also supports
the updating of the components using update attribute.
Example:
Now, reconsider the above example with similar drop-downs (but disabled with fixed values). Now you know that your screen has nothing to be updated and you just have to tackle with validation (if any) and submit the form (update if required).
As far as you are concerned with using the p:ajax on the p:inputText for some asynchronously updates on the screen and p:commandButton to finally submit the form, that totally depends on your requriement.
Instead p:ajax try f:ajax. You can use < f:ajax event="change" render="#this"/>
once the value gets change, same will reflect in backing bean.
I try to get experiment with ajax. I want that string from inputText typing to outpuLabel.
<h:form>
<h:inputText id="str" value="#{f.str}">
<f:ajax render="num"/>
</h:inputText>
<h:outputLabel id="num" value="#{f.str}">
</h:outputLabel>
</h:form>
But the value of num update only when i'm typed and clicked the mouse, not during typing to str. How do that the num will be updating during the typing?
The <f:ajax event> defaults in case of UIInput components to valueChange which renders in case of <h:inputText> the ajax call in the onchange attribute of the generated <input type="text"> element (you can see it yourself by opening the JSF page in webbrowser and do rightclick and View Source).
So, the ajax request is only fired when the HTML DOM change event is fired. That is, when you change the value of the input element and then the input element loses focus (blurs).
As per your functional requirement, you actually want the ajax request to be fired when the HTML DOM keyup event is fired. In that case, you'd need to explicitly specify that.
<f:ajax event="keyup" ... />
See also:
What values can I pass to the event attribute of the f:ajax tag?
I have a problem with a JSF 2 form that contains an ajax field. When I use the mouse to press the submit button of the form while the cursor is still in the ajaxified input field the input value of the field does not get submitted before the action is triggered in the backing bean. Also the attached validator and converter are not triggered.
<h:form id="invoice">
...
<h:inputText value="#{invoiceBean.amount}" required="true" validator="#{invoiceBean.validateAmount}">
<f:converter converterId="CurrencyConverter" />
<f:ajax event="blur" render="#this"/>
</h:inputText>
<h:commandButton action="#{invoiceBean.processInvoice()}" />
</h:form>
I also tried to enhance the command button with <f:ajax /> but the result stayed the same. Other (non-ajax) fields on the same form (not shown in the code snippet above) are submitted correctly. The ajax field is also submitted, converted and validated if I click somwhere else on the page before submitting but not when using the button directly.
Is there anything I am missing to have the field also be submitted on/before form submit?
Regarding the <h:inputText> ajax behaviour: use <f:ajax> with the default event valueChange, which is the default event for all input components. This is indeed equivalent to omitting the event attribute:
<f:ajax render="#this" />
Regarding the <h:commmandButton> component, don't forget to specify the execute attribute of <f:ajax>:
<f:ajax execute="#form" />
otherwise it will default to #this, therefore rendering vane your effort.
I've noticed that this doesn't work for me and I'm wondering if it's just not possible:
<h:form id="one" prependid="false" >
<h:commandButton>
<f:ajax execute=":two">
</h:commandButton>
</h:form>
<h:form id="two" prependid="false">
... content ...
</h:form>
Whenever I click the button above ,I can see that the values on form two are not executed as expected.
Is this the normal JSF behavior?
To 'trick' it, I usually insert a hidden button in form two and trigger it using JavaScript code when the button in form one is clicked. But that's a 'trick' and makes me work extra when I'm not sure I have to.
I should mention the rendering another form is possible.
Could the prependid attribute be causing problems?
Thanks in Advance!
UPDATE Adding more information that might be relevant - adding the prependid="false" to the forms as it is used in the actual code.
No, that's not possible with <f:ajax>. It just submits the parent form. The execute merely tells JSF which components it has to process based on the submitted data, not which request parameters the client side have to send. The button has really to go in the form where it belongs.
I have a form with a validator on one field. I have two h:commandButtons: Ok and Cancel. When I input wrong data and click Cancel, I get a validation message. What must I do that validator don't run when I click cancel?
In case you aren't using ajax, or are still on JSF 1.x, and you really need to invoke a business action in cancel() method (i.e. just reloading the page is insufficient), then your best bet is to add immediate="true" to the button. This way all input fields which don't have immediate="true" will be skipped in processing.
<h:commandButton value="Cancel" action="#{bean.cancel}" immediate="true" />
On JSF 2.x, much better is to submit the form by <f:ajax>, which by default only processes #this instead of #form.
<h:commandButton value="Cancel" action="#{bean.cancel}">
<f:ajax />
</h:commandButton>
If you want to navigate to another page here, add ?faces-redirect=true to the outcome in the cancel() method.
Or, if you actually don't need to invoke any business action at all, then just use <h:button> wherein you directly specify the (implicit) navigation case outcome.
<h:button value="Cancel" outcome="previouspage" />
This will basically reload the page by a GET request. The <h:button> doesn't exist in JSF 1.x, but you can also just use plain HTML+JS for that.
See also:
Why was "immediate" attribute added to the EditableValueHolders?
How to navigate in JSF? How to make URL reflect current page (and not previous one)
How to let validation depend on the pressed button?