How to generate primefaces PickList component programmatically? - jsf

Question

public void populateForm(ComponentSystemEvent event) {
HtmlForm form = (HtmlForm) event.getComponent();
List<String> citiesSource = new ArrayList<String>();
List<String> citiesTarget = new ArrayList<String>();
citiesSource.add("San Francisco");
citiesSource.add("London");
citiesSource.add("Paris");
citiesSource.add("Istanbul");
citiesSource.add("Berlin");
citiesSource.add("Barcelona");
citiesSource.add("Rome");
cities = new DualListModel<String>(citiesSource, citiesTarget);
PickList pickList = new PickList();
pickList.setId("pickList");
pickList.setValue(cities);
pickList.setVar("cities");
pickList.setItemLabel(pickList.getVar());
pickList.setItemValue(cities);
form.getChildren().add(pickList);
}
This was my approach, and output I got is:
But if I add <p:pickList id="pickList" value="#{bean.cities}" var="cities" itemLabel="#{cities}" itemValue="#{cities}" /> in my xhtml, I get this output:
What is going on here?

Answer 1

This is how I solved the PickList issue:
FacesContext context = FacesContext.getCurrentInstance();
ExpressionFactory ef = context.getApplication().getExpressionFactory();
PickList pickList = new PickList();
ValueExpression pickListValue = ef.createValueExpression(
context.getELContext(), "#{ruleManagedBean.cities}",DualListModel.class);
ValueExpression pickListVar = ef.createValueExpression(
context.getELContext(), "cities", String.class);
ValueExpression pickListItemLabel = ef.createValueExpression(
context.getELContext(), "#{cities}", String.class);
ValueExpression pickListItemValue = ef.createValueExpression(
context.getELContext(), "#{cities}", String.class);
pickList.setId("pickList");
pickList.setValueExpression("value", pickListValue);
pickList.setValueExpression("var", pickListVar);
pickList.setValueExpression("itemLabel", pickListItemLabel);
pickList.setValueExpression("itemValue", pickListItemValue);
form.getChildren().add(pickList);
Note: ruleManagedBean.cities refers to the DualListModel, populated as
List<String> citiesSource = new ArrayList<String>();
List<String> citiesTarget = new ArrayList<String>();
citiesSource.add("San Francisco");
citiesSource.add("London");
citiesSource.add("Paris");
citiesSource.add("Istanbul");
citiesSource.add("Berlin");
citiesSource.add("Barcelona");
citiesSource.add("Rome");
cities.setSource(citiesSource);
cities.setTarget(citiesTarget);
Make sure that you have declared this DualListModel globally as below and has getter setter methods
private DualListModel<String> cities = new DualListModel<String>();

Answer 2

Instead of PickList pickList = new PickList(); try this:
Application application = FacesContext.getCurrentInstance().getApplication();
PickList pickList = (PickList) application.createComponent(PickList.COMPONENT_TYPE);
Change your pickList.setValue(cities); for this:
Note: cities must be a field on your bean with its own getter.
ExpressionFactory ef = application.getExpressionFactory();
ELContext elc = FacesContext.getCurrentInstance().getELContext();
ValueExpression value = ef.createValueExpression(elc, "#{bean.cities}", DualListModel.class);
pickList.setValueExpression("value", value);