I use tip from this post https://stackoverflow.com/a/13838907 to open new tab, however when I go back to old one I get nullPointerException and my ViewScoped bean data are lost.
<h:form target="_blank">
<p:commandButton value="open new tab" action="#{otherBean.newTab}" ajax="false" />
</h:form>
<h:form>
<p:commandButton value="this wll cause NPE" action="#{pageBean.action}"/>
</h:form>
Click first button, go back to previous tab, click second button. PageBean is created once again and all data are lost. Both beans are ViewScoped.
Indeed, the view scoped bean in the initial tab/window get killed by returning a String navigation case outcome. You would like to return null or void to keep it alive. Based on the newTab() code as shown in your other question, you need to replace the navigation case by a Faces#redirect() call (assuming that it's indeed OmniFaces which you're using there for Faces#setFlashAttribute()). You only need to set Flash#setRedirect() to true beforehand to instruct the flash scope that a redirect will occur.
public void newTab() throws IOException {
Faces.setFlashAttribute("foo", bar);
Faces.getFlash().setRedirect(true);
Faces.redirect("otherView.xhtml");
}
ViewScope beans only live as long as you post back to same view.
If you post back to other views in your action data will be lost since the ViewScope bean will be recreated.
Related
I have a <p:dialog> in my general layout. I have its Header attribute hardcoded at the moment.
What I want is to access it from different beans and change its Header at run-time according to my choice.
I am using it to show a loading message to the user at the moment and want to update the loading text according to the current backend processing, e.g "waiting for server's response" etc.
<p:dialog id="main-status-dialog"
widgetVar="mainStatusDialog"
modal="true"
header="Loading..."
draggable="false"
closable="false"
resizable="false"
appendToBody="true">
Now I am calling it from different JSF pages on button clicks e.g <h:link outcome="/generalInformation" value="General Information" onclick="mainStatusDialog.show()" />
It works fine but always Show me "Loading..." because I have a hardcoaded Attribute. So how can I make it dynamic? Please note that I don't want to do it only for one page or bean, but from any page it Access it, i can Change ist Header accordingly.
Thanks!
You can use a managed property with #ManagedProperty of one of your managed beans (e.g HeaderBean)and change it every time accordingly and set the header value to this value, and it whould look dynamically updated.
#ManagedProperty("#{headerBean}")
private HeaderBean headerBean;
And in your header managed bean make a String property value where you will store the value of the header:
#ManagedBean(name = "headerBean")
#RequestScoped
public class HeaderBean implements Serializable
{
private String value = null;
// getter and setter methods
And in your p:dialog:
<p:dialog id="main-status-dialog"
widgetVar="mainStatusDialog"
modal="true"
header="#{headerBean.value}"
draggable="false"
closable="false"
resizable="false"
appendToBody="true">
Take a look at the following liks to find more about it:
The BalusC Code: Communication in JSF 2.0
Injecting Managed beans in JSF 2.0
#ManagedProperty - Inject one request scoped bean into another request scoped bean
EDIT:
You can use RequestContext to update the dialog from your beans, If you take a look at Better ajax operations and callbacks in JSF with PrimeFaces you will see that:
RequestContext API enables developers to do 2 simple things. 1st you can tell what you want to update in the xhtml based on conditions in actions that you define in your Managed Beans.To update a component from serverside, you can just write:
The code you need to update the p:dialog from your managed beans is:
RequestContext.getCurrentInstance().
addPartialUpdateTarget("header_id");
You can also use update attribute in your commandLink like this:
<h:link outcome="/generalInformation" value="General Information" oncomplete="mainStatusDialog.show()" update=":main-status-dialog"/>
I have a ViewScoped Managed Bean. In my .xhtml page I want to set bean's attribute's value and use it in methods in the same bean.
I managed to set the value from jsf page, but when i want to use it in some method the value of an attribute is not the value i have set before.
Description (xhtml):
In this form there is a command link which sets the value of an attribute. And it is working fine. Also, as command link is clicked, second form is being showed.
<h:form>
<h:commandLink value="Set" >
<f:setPropertyActionListener target="#{bean.attribute}" value="true" />
<f:ajax execute="#this" />
</h:commandLink>
</h:form>
This form executes method that uses attribute's value set before, but the value is not true, its false.
<h:form>
<h:commandButton id="submit" value="Execute" action="#{bean.execute}" />
</h:form>
Bean:
public void execute(){
if(isAttribute())
---do something---
}
The question is: Why execute() is not reading attribute's value right?
When I use one form, it's working fine. But I need them to be in separated forms.
The scope of your bean is incorrect. ViewScoped means that the minute the view is changed, the bean is discarded and re-created for the next view. So, in your case, the original data you had for the first view is lost.
I'm going to refer you to BalusC's blog:
http://balusc.blogspot.co.uk/2010/06/benefits-and-pitfalls-of-viewscoped.html
which states:
A #ViewScoped bean will live as long as you're submitting the form to the same view again and again. In other words, as long as when the action method(s) returns null or even void, the bean will be there in the next request. Once you navigate to a different view, then the bean will be trashed
I can't determine of you stay on the same page with both requests. If you do, viewScope should work even in two different forms. If you are navigating from 1 view to another, another viewScope will be created and you will loose the current one.
You could set the value in the sessionScope with java or by annotating the backingNean. But then everything in your backingBean becomes sessionScoped and that might not be needed.
You could also use a spring-like flow scope.
Example to do it with java:
public void callThisAfterFirstClick() {
Faces.setSessionAttribute(attribute, true)
}
public void callThisAfterSecondClick() {
Faces.getSessionAttribute(attribute);
}
I'm trying to create a button that once clicked will change a property in a bean.
<h:commandButton type="button" action="#{loginBean.withdraw}" id="thousand" class="buttons" style="top:180px;left:570px;">
<f:setPropertyActionListener target="#{loginBean.withdrawAmount}" value="1000" />
</h:commandButton>
public class LoginBean {
int withdrawAmount;
This method only works when I omit the type="button" from the commandButton, but with the type="button" it doesn't work and I'm not sure why.
I need the type="button" to be there , is there any way to keep it and still make it work ?
There is an error in your facelet snippet:
There is no such attribute as class for <h:commandButton>. Possibly you meant styleClass.
As for the problem you have, you have to:
Either provide a setter method for the withdrawAmount property
public void setWithdrawAmount(int withdrawAmount) {
this.withdrawAmount = withdrawAmount;
}
and your facelet should look like:
<h:commandButton type="submit"
action="#{loginBean.withdraw}"
id="thousand"
styleClass="buttons"
style="top:180px;left:570px;">
<f:setPropertyActionListener target="#{loginBean.withdrawAmount}"
value="1000" />
</h:commandButton>
Or, you can get rid of the <f:setPropertyActionListener> and add a statement the changes the value of the withdrawAmount as a first line of the #{loginBean.withdraw} method.
In this case your facelet snippet should look like:
<h:commandButton type="submit"
action="#{loginBean.withdraw}"
id="thousand"
styleClass="buttons"
style="top:180px;left:570px;" />
and your LoginBean#withdraw() method should start with the statement, that changes the withdrawAmount value:
public String withdraw() {
this.withdrawAmount = 1000;
//the remaining logic.
}
Personally, I would prefer the first option.
More info:
< h:commandButton > tag reference
JSF Core Tag :setPropertyActionListener vs attribute vs param
The type is the entire reason why you're having this issue. I'm posting this answer because the accepted answer doesn't explain why you're experiencing the issue.
<h:commandButton/> is designed to work in 3 modes:
submit: This is the default mode that the button is set to. This mode sends an HTTP POST request to the server that triggers the JSF request processing lifecycle. It's only this mode that enables you to trigger backing bean methods(using the action or actionListener attributes).
button: This mode triggers a GET request in the application. As GET requests go, this mode is mostly suited for navigation, i.e. requesting another view or page. In this mode, there's no easy/straightforward way to execute backing bean code, or trigger the JSF request processing lifecycle. This is your current issue
reset: This mode simply resets the value of all input components within its enclosing <h:form/>
Reference:
JSF2 Command Button VDL
JSF redirect via commandButton
Difference between h:button and h:commandButton
How can I open new tab when user clicks p:commandButton? I also want to pass some parameters to new page using FlashScope. Here's the code:
<h:form>
<p:commandButton value="open new tab" action="#{myBean.newTab}"/>
</h:form>
public String newTab() {
Faces.setFlashAttribute("foo", bar);
return "otherView";
}
On the otherView page I use f:event type="preRenderView" to read Flash parameters.
Two notes:
I need to use FlashScope, not URL parameters.
If possible, I don't want to change newTab() and preRenderView() methods.
Thanks for help
Use target="_blank" on the form to tell the browser that the synchronous response of the form should be presented in a new (blank) tab/window. You only need to turn off ajax behaviour of the <p:commandButton> in order to make it a synchronous request.
<h:form target="_blank">
<p:commandButton value="open new tab" action="#{myBean.newTab}" ajax="false" />
</h:form>
No changes are necessary in the backing beans, it'll just work as you intented. I would only recommend to use POST-Redirect-GET pattern in the action method.
return "otherView?faces-redirect=true";
Otherwise the new tab would show the URL of the originating page and a F5 would re-invoke the POST. Also, this way the flash scope is also really used as it is been designed for (if you didn't redirect, just storing in request scope was been sufficient).
Update: as per the comments, the view scoped bean in the initial tab/window get killed this way. by returning a String navigation case outcome. That's right, if you'd like to keep the view scoped bean alive, replace the navigation case by a Faces#redirect() call (assuming that it's indeed OmniFaces which you're using there for Faces#setFlashAttribute()). You only need to set Flash#setRedirect() to true beforehand to instruct the flash scope that a redirect will occur.
public void newTab() throws IOException {
Faces.setFlashAttribute("foo", bar);
Faces.getFlash().setRedirect(true);
Faces.redirect("otherView.xhtml");
}
I have a problem that i don't understand:
I request a new site. A site has a link that opens a dialog. The link is inside a form.
The dialog is not inside the form.
A reduced code example:
<p:outputPanel id="layout-center" >
<h:form>
<p:commandLink id="option_field_user_profile" actionListener="#{controllerBean.getBean('userProfileBean', component).init}" oncomplete="#{controllerBean.getBean('userProfileBean', component).show}" >
<h:outputText value="#{msg.mProfile}"/>
</p:commandLink>
</h:form>
</p:outputPanel>
<p:dialog header="#{userPreferencesBean.header}" widgetVar="#{userPreferencesBean.widgetVar}" appendToBody="#{userPreferencesBean.appendToBody}" resizable="#{userPreferencesBean.resizable}" id="#{userPreferencesBean.xhtmlId}" dynamic="#{userPreferencesBean.dynamic}" modal="#{userPreferencesBean.modal}" closable="#{userPreferenceBean.closable}">
<ui:include src="/WEB-INF/templates/modification/userPreferences.xhtml" />
</p:dialog>
UserPreferencesBean is in ViewScope. My problem is now that the #PostConstruct method from the UserPreferencesBean is called twice with the non-postback request i.e. the Bean is constructed twice although it should be the same view. If i move the dialog inside the form for testing purposes it is called once, like expected. But since the dialog has its own form this is not a solution, for sure.
When the site is loaded and I hit F5, the PostConstruct method is executed once.
Has somebody an idea?
This is caused because you referenced a view scoped bean property in the view build time attribute id of the <p:dialog>. If you fix the id to be static, or to reference a request or application scoped bean property instead, then your view scoped bean will behave as expected.
See also:
JSTL in JSF2 Facelets... makes sense? - for some background explanation on view build time and view render time; the id and binding attributes of UI components are evaluated during view build time.