问题
We have an ajax navigation menu which updates a dynamic include. The include files have each their own forms.
<h:form>
<h:commandButton value=\"Add\" action=\"#{navigator.setUrl(\'AddUser\')}\">
<f:ajax render=\":propertiesArea\" />
</h:commandButton>
</h:form>
<h:panelGroup id=\"propertiesArea\" layout=\"block\">
<ui:include src=\"#{navigator.selectedLevel.url}\" />
</h:panelGroup>
It works correctly, but any command button in the include file doesn\'t work on first click. It works only on second click and forth.
I found this question commandButton/commandLink/ajax action/listener method not invoked or input value not updated and my problem is described in point 9.
I understand that I need to explicitly include the ID of the <h:form> in the include in the <f:ajax render> to solve it.
<f:ajax render=\":propertiesArea :propertiesArea:someFormId\" />
In my case, however, the form ID is not known beforehand. Also this form will not be available in the context initally.
Is there any solution to the above scenario?
回答1:
You can use the following script to fix the Mojarra 2.0/2.1/2.2 bug (note: this doesn't manifest in MyFaces). This script will create the javax.faces.ViewState hidden field for forms which did not retrieve any view state after ajax update.
jsf.ajax.addOnEvent(function(data) {
if (data.status == "success") {
fixViewState(data.responseXML);
}
});
function fixViewState(responseXML) {
var viewState = getViewState(responseXML);
if (viewState) {
for (var i = 0; i < document.forms.length; i++) {
var form = document.forms[i];
if (form.method == "post") {
if (!hasViewState(form)) {
createViewState(form, viewState);
}
}
else { // PrimeFaces also adds them to GET forms!
removeViewState(form);
}
}
}
}
function getViewState(responseXML) {
var updates = responseXML.getElementsByTagName("update");
for (var i = 0; i < updates.length; i++) {
var update = updates[i];
if (update.getAttribute("id").match(/^([\w]+:)?javax\.faces\.ViewState(:[0-9]+)?$/)) {
return update.textContent || update.innerText;
}
}
return null;
}
function hasViewState(form) {
for (var i = 0; i < form.elements.length; i++) {
if (form.elements[i].name == "javax.faces.ViewState") {
return true;
}
}
return false;
}
function createViewState(form, viewState) {
var hidden;
try {
hidden = document.createElement("<input name='javax.faces.ViewState'>"); // IE6-8.
} catch(e) {
hidden = document.createElement("input");
hidden.setAttribute("name", "javax.faces.ViewState");
}
hidden.setAttribute("type", "hidden");
hidden.setAttribute("value", viewState);
hidden.setAttribute("autocomplete", "off");
form.appendChild(hidden);
}
function removeViewState(form) {
for (var i = 0; i < form.elements.length; i++) {
var element = form.elements[i];
if (element.name == "javax.faces.ViewState") {
element.parentNode.removeChild(element);
}
}
}
Just include it as <h:outputScript name="some.js" target="head"> inside the <h:body> of the error page. If you can't guarantee that the page in question uses JSF <f:ajax>, which would trigger auto-inclusion of jsf.js, then you might want to add an additional if (typeof jsf !== 'undefined') check before jsf.ajax.addOnEvent() call, or to explicitly include it by
<h:outputScript library="javax.faces" name="jsf.js" target="head" />
Note that jsf.ajax.addOnEvent only covers standard JSF <f:ajax> and not e.g. PrimeFaces <p:ajax> or <p:commandXxx> as they use under the covers jQuery for the job. To cover PrimeFaces ajax requests as well, add the following:
$(document).ajaxComplete(function(event, xhr, options) {
if (typeof xhr.responseXML != 'undefined') { // It's undefined when plain $.ajax(), $.get(), etc is used instead of PrimeFaces ajax.
fixViewState(xhr.responseXML);
}
}
Update if you're using JSF utility library OmniFaces, it's good to know that the above has since 1.7 become part of OmniFaces. It's just a matter of declaring the following script in the <h:body>. See also the showcase.
<h:body>
<h:outputScript library="omnifaces" name="fixviewstate.js" target="head" />
...
</h:body>
回答2:
Thanks to BalusC since his answer is really great (as usual :) ). But I have to add that this approach does not work for ajax requests coming from RichFaces 4. They have several issues with ajax and one of them is that the JSF-ajax-handlers are not being invoked. Thus, when doing a rerender on some container holding a form using RichFaces-components, the fixViewState-function is not called and the ViewState is missing then.
In the RichFaces Component Reference, they state how to register callbacks for "their" ajax-requests (in fact they're utilizing jQuery to hook on all ajax-requests). But using this, I was not able to get the ajax-response which is used by BalusC's script above to get the ViewState.
So based on BalusC's fix, i worked out a very similar one. My script saves all ViewState-values of all forms on the current page in a map before the ajax-request is being processed by the browser. After the update of the DOM, I try to restore all ViewStates which have been saved before (for all forms which are missing the ViewState now).
Move on:
jQuery(document).ready(function() {
jQuery(document).on("ajaxbeforedomupdate", function(args) {
// the callback will be triggered for each received JSF AJAX for the current page
// store the current view-states of all forms in a map
storeViewStates(args.currentTarget.forms);
});
jQuery(document).on("ajaxcomplete", function(args) {
// the callback will be triggered for each completed JSF AJAX for the current page
// restore all view-states of all forms which do not have one
restoreViewStates(args.currentTarget.forms);
});
});
var storedFormViewStates = {};
function storeViewStates(forms) {
storedFormViewStates = {};
for (var formIndex = 0; formIndex < forms.length; formIndex++) {
var form = forms[formIndex];
var formId = form.getAttribute("id");
for (var formChildIndex = 0; formChildIndex < form.children.length; formChildIndex++) {
var formChild = form.children[formChildIndex];
if ((formChild.hasAttribute("name")) && (formChild.getAttribute("name").match(/^([\w]+:)?javax\.faces\.ViewState(:[0-9]+)?$/))) {
storedFormViewStates[formId] = formChild.value;
break;
}
}
}
}
function restoreViewStates(forms) {
for (var formIndexd = 0; formIndexd < forms.length; formIndexd++) {
var form = forms[formIndexd];
var formId = form.getAttribute("id");
var viewStateFound = false;
for (var formChildIndex = 0; formChildIndex < form.children.length; formChildIndex++) {
var formChild = form.children[formChildIndex];
if ((formChild.hasAttribute("name")) && (formChild.getAttribute("name").match(/^([\w]+:)?javax\.faces\.ViewState(:[0-9]+)?$/))) {
viewStateFound = true;
break;
}
}
if ((!viewStateFound) && (storedFormViewStates.hasOwnProperty(formId))) {
createViewState(form, storedFormViewStates[formId]);
}
}
}
function createViewState(form, viewState) {
var hidden;
try {
hidden = document.createElement("<input name='javax.faces.ViewState'>"); // IE6-8.
} catch(e) {
hidden = document.createElement("input");
hidden.setAttribute("name", "javax.faces.ViewState");
}
hidden.setAttribute("type", "hidden");
hidden.setAttribute("value", viewState);
hidden.setAttribute("autocomplete", "off");
form.appendChild(hidden);
}
Since I am not an JavaScript-expert, I guess that this may be improved further. But it definitely works on FF 17, Chromium 24, Chrome 12 and IE 11.
Two additional questions to this approach:
Is it feasible to use the same ViewState-value again? I.e. is JSF assigning the same ViewState-value to each form for every request/response? My approach is based on this assumption (and I have not found any related information).
Does someone expect any problems with this JavaScript-code or already ran into some using any browser?
来源：https://stackoverflow.com/questions/11408130/hcommandbutton-hcommandlink-does-not-work-on-first-click-works-only-on-second