Hi Caroline,
Caroline Jen wrote:
...
> Meanwhile, would you mind advising:
>
You want to clear the selected Items?
just clear or null the field in the bean.
public void clear(ActionEvent e)
{
FacesContext facesContext =
FacesContext.getCurrentInstance();
ValueBinding vb = e.getComponent().getValueBinding();
if (vb != null) {
vb.setValue(facesContext, null);
}
}
> 1. How do I deliver each element of the Object[]
> selectedItems into this method:
>
> public void clear(ActionEvent e)
> {
> FacesContext facesContext =
> FacesContext.getCurrentInstance();
> UIViewRoot uiViewRoot =
> facesContext.getViewRoot();
>
> // Here, I want to iterating through the Object[]
> if (selectedItems[i] instanceof
> EditableValueHolder)
> {
this can never happen, selectedItems[i] is not an instance of
EditableValueHolder !
selectedItems[i] is the first argument of SelectItem constructor:
String in my example.
> EditableValueHolder evh = (EditableValueHolder)
> selectedItems[i];
> evh.setSubmittedValue(null);
This has no effect in application phase.
just setting a variable to null and throwing away afterwards.
> }
> }
>
> The code snippet above is a draft. I am uncertain if
> I am doing it right.
>
> 2. The multiple selections made by user are in an
> Object array (i.e. Object[] selectedItems). How do I
> retrieve the values from this Object array (I think
Just fetch them from your bean or via ValueBinding from your Component.
> that the values retrieved will be a String[] if I am
> not terribly wrong.) to be sent to the database?
The type is the array type of the objects used to create the
selectItems, in my example Strings.
I attached updated TestBean.java and test.jsp with examples.
Regards
Volker Weber
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package org.apache.myfaces.examples;
import javax.faces.component.UISelectMany;
import javax.faces.component.UISelectItems;
import javax.faces.model.SelectItem;
import javax.faces.event.ActionEvent;
import javax.faces.context.FacesContext;
import javax.faces.el.ValueBinding;
import java.util.List;
import java.util.ArrayList;
public class TestBean {
private UISelectMany selectMany;
private Object[] selectedItems;
public TestBean() {
selectMany = new UISelectMany();
selectMany.setId("selectMany");
UISelectItems items = new UISelectItems();
items.setId("selectManyItems");
items.setValue(createSelectItems());
selectMany.getChildren().add(items);
}
private Object createSelectItems() {
List items = new ArrayList();
for (int i = 0; i < 10; i++){
items.add(new SelectItem("item" + i, "Item No. " + i));
}
return items;
}
public UISelectMany getSelectMany() {
return selectMany;
}
public void setSelectMany(UISelectMany selectMany) {
this.selectMany = selectMany;
}
public Object[] getSelectedItems() {
return selectedItems;
}
public void setSelectedItems(Object[] selectedItems) {
this.selectedItems = selectedItems;
}
public void clear(ActionEvent e) {
selectedItems = null;
// or if no direct access possible
// FacesContext facesContext =
// FacesContext.getCurrentInstance();
// ValueBinding vb = e.getComponent().getValueBinding("value");
// if (vb != null) {
// vb.setValue(facesContext, null);
// }
// ! we have to clear itemsDisplay here also !
// otherwise it holds his value until next submit click.
itemsDisplay = null;
}
private String itemsDisplay;
public void submit(ActionEvent e){
Object[] items;
items = selectedItems;
// or if no direct access possible
// FacesContext facesContext =
// FacesContext.getCurrentInstance();
// ValueBinding vb = e.getComponent().getValueBinding("value");
// if (vb != null) {
// items = vb.getValue(facesContext);
// }
if (items == null || items.length == 0) {
itemsDisplay = "No items selected!";
} else {
StringBuffer sb = new StringBuffer("Selected Items: ");
for (int i = 0; i < items.length; i++) {
sb.append(items[i]);
sb.append("; ");
}
itemsDisplay = sb.toString();
}
}
public String getItemsDisplay() {
return itemsDisplay;
}
}
<%@ page import="org.apache.myfaces.examples.TestBean"%>
<%@ taglib uri="http://java.sun.com/jsf/html"; prefix="h"%>
<%@ taglib uri="http://java.sun.com/jsf/core"; prefix="f"%>
<%
Object testbean = pageContext.getAttribute("TestBean",
PageContext.SESSION_SCOPE);
if (testbean == null) {
pageContext.setAttribute("TestBean", new TestBean(),
PageContext.SESSION_SCOPE);
}
%>
<html>
<body>
<f:view>
<h:form>
<h:selectManyListbox id="selectMany"
binding="#{TestBean.selectMany}"
value="#{TestBean.selectedItems}" />
<br>
<h:commandButton value="Submit" actionListener="#{TestBean.submit}"/>
<h:commandButton value="Clear" actionListener="#{TestBean.clear}"/>
<br>
<br>
<h:outputText value="#{TestBean.itemsDisplay}"/>
</h:form>
</f:view>
</body>
</html>
