如何在ajax方法中获取被单击的项目？

如何在ajax方法中获取被单击的项目？

因此，您不仅对新值感兴趣，而且对实际值更改感兴趣。引入一个

valueChangeListener

将旧值与新值进行比较的a
，并准备一些ajax侦听器方法可以拦截的属性。

例如

<h:selectManyCheckbox value="#{bean.selectedItems}" valueChangeListener="#{bean.selectedItemsChanged}" converter="javax.faces.Long">    <f:selectItems value="#{bean.availableItems}" />    <f:ajax listener="#{bean.itemSelected}" /></h:selectManyCheckbox>

与

private Map<String, Long> availableItems; // +getterprivate List<Long> selectedItems; // +getter+setterprivate Long selectedItem;private boolean selectedItemRemoved;@PostConstructpublic void init() {    availableItems = new linkedHashMap<String, Long>();    for (long i = 0; i < 10; i++) {        availableItems.put("CHKID " + i, i);    }}public void selectedItemsChanged(ValueChangeEvent event) {    List<Long> oldValue = (List<Long>) event.getOldValue();    List<Long> newValue = (List<Long>) event.getNewValue();    if (oldValue == null) {        oldValue = Collections.emptyList();    }    if (oldValue.size() > newValue.size()) {        oldValue = new ArrayList<Long>(oldValue);        oldValue.removeAll(newValue);        selectedItem = oldValue.iterator().next();        selectedItemRemoved = true;    }    else {        newValue = new ArrayList<Long>(newValue);        newValue.removeAll(oldValue);        selectedItem = newValue.iterator().next();        selectedItemRemoved = false;    }}public void itemSelected(AjaxBehaviorEvent event) {    System.out.println("Selected item: " + selectedItem);    System.out.println("Selected item removed? " + selectedItemRemoved);}