How to use Converter in NativeSelect

Vaadin 6 / 7 / 8 Framework UI
1

Hi, I have a Boolean (or enum) data and want to display in NativeSelect in String model:

@Override
protected void init(VaadinRequest request) {
    
    final VerticalLayout layout = new VerticalLayout();
    layout.setMargin(true);
    setContent(layout);

    String YES = "Yes";
    String NO ="No";
    
    final NativeSelect select = new NativeSelect("Choose");
    select.addItems(Arrays.asList(new String[]{YES, NO}));
    select.setNullSelectionAllowed(false);
    
    Boolean dateModelValue = Boolean.FALSE;

// StringToBooleanConverter converter = new StringToBooleanConverter(“Yes”,“No”);
// select.setValue(converter);

/* // case 1
select.setConverter(Boolean.class);
select.setValue(dateModelValue);

    // case 2
    select.setConverter(String.class);
    select.setValue(dateModelValue);

*/
// case 3
select.setConverter(Boolean.class);
select.setValue(NO);

    // case 4

/* select.setConverter(String.class);
select.setValue(NO);
*/
select.addValueChangeListener(new ValueChangeListener() {
@Override
public void valueChange(ValueChangeEvent event) {
Notification.show(String.format(“value=%s, converted value=%s”, select.getValue(), select.getConvertedValue()));
}
});

    layout.addComponent(select);
}

I assume that setConvert(…) could support vaule return Boolean and converted value String, or in contrast.

  1. public void setConverter(Class<?> datamodelType) - test 4 cases above, the results are not as wanted.
  2. setConverter(Converter<T, ?> converter) - report StringToBooleanConverter is not applicable for the arguments.

So my question is whether setConvert(…) supports NativeSelect for the purpose. if yes, how.

2

Hi,
setConverter(Class<?> datamodelType) takes the converter from a ConvertFactory. In case of Boolean.class the StringToBooleanConverter is used.
StringToBooleanConverter by default map the strings “true” and “false” to the equivalent boolean values, but you can change this mapping

new StringToBooleanConverter(YES, NO); In case of NativeSelect you should use an unchecked assingment in setConverter(…) because NativeSelect, due to type parameter, expects a Converter<Object, ?> whereas StringToBooleanConverter is a Converter<String, Boolean>

Converter converter = new StringToBooleanConverter(YES, NO);
select.setConverter(converter);

HTH
Marco

3

Thanks Marco, it works.