How to Restrict deselecting all items in smartgwt SelectItem with multiple selection enabled?

Question

I´m using the SelectItem component with configuration:

SelectItem selectItem = new SelectItem("SelectItem");
selectItem.setShowTitle(false);
selectItem.setMultiple(true);
selectItem.setMultipleValueSeparator(",");
selectItem.setDefaultValue("1");

Now I want to restrict user to deselecting all items,at least one item must be selected.

Can anybody help me how to restrict?

Answer 1

Hy Suresh,

here is the quick fix!

In my example you need to use second SelectItem for saving purpose and FocusHandler.

My example:

LinkedHashMap<String, String> valueMap = new LinkedHashMap<>();
    valueMap.put("a", "a");
    valueMap.put("b", "b");
    valueMap.put("c", "c");
    valueMap.put("d", "d");
    valueMap.put("e", "e");
    valueMap.put("f", "f");

    final SelectItem saveSelectedItem = new SelectItem();
    saveSelectedItem.setMultiple(true);
    saveSelectedItem.setValueMap(valueMap);

    final SelectItem selectedItem = new SelectItem();
    selectedItem.setDefaultValue("Default");
    selectedItem.setMultiple(true);
    selectedItem.setTitle("Select: ");
    selectedItem.setValueMap(valueMap);
    selectedItem.addFocusHandler(new FocusHandler() {

        @Override
        public void onFocus(FocusEvent event) {
            if(selectedItem.getValue() == null){
                selectedItem.setValue(saveSelectedItem.getValue());
            }else {
                saveSelectedItem.setValue(selectedItem.getValue());
            }               
        }
    });

So user will be able to un/select all values, but value will be set to last selected value in SelectItem field.

Hope int helps.

Regards Jakov A.