public class ComboBox<T>

A ComboBox is a list that allows only one selection at a time, when a user clicks the ComboBox a popup button with the full list of elements allows the selection of a single element. The ComboBox is driven by the list model and allows all the renderer features of the List as well.

The ComboBox is notoriously hard to style properly as it relies on a complex dynamic of popup renderer and instantly visible renderer. The UIID for the ComboBox is “ComboBox” however if you set it to something else all the other UIID’s will also change their prefix. E.g. the “ComboBoxPopup” UIID will become “MyNewUIIDPopup”.

The combo box defines the following UIID’s by default:

• ComboBox

• ComboBoxItem

• ComboBoxFocus

• PopupContentPane

• PopupItem

• PopupFocus

This class also defines theme constants that allow some native themes to manipulate its behavior e.g.:

• popupTitleBool - shows the “label for” value as the title of the popup dialog

• popupCancelBodyBool - Adds a cancel button into the popup dialog

• centeredPopupBool - shows the popup dialog in the center of the screen instead of under the popup

• otherPopupRendererBool - Uses a different list cell render for the popup than the one used for the ComboBox itself. When this is false PopupItem & PopupFocus become irrelevant. Notice that the Android native theme defines this to true.

iOS doesn’t use combo boxes as part of its UI paradigm. Its available there mostly in web applications and feels unnatural in iOS which is why we recommend using the com.codename1.ui.spinner.Picker class.

The sample code below uses the com.codename1.ui.list.GenericListCellRenderer to create a richer ComboBox UI.

public void showForm() {
  Form hi = new Form("ComboBox", new BoxLayout(BoxLayout.Y_AXIS));
  ComboBox> combo = new ComboBox<> (
          createListEntry("A Game of Thrones", "1996"),
          createListEntry("A Clash Of Kings", "1998"),
          createListEntry("A Storm Of Swords", "2000"),
          createListEntry("A Feast For Crows", "2005"),
          createListEntry("A Dance With Dragons", "2011"),
          createListEntry("The Winds of Winter", "2016 (please, please, please)"),
          createListEntry("A Dream of Spring", "Ugh"));

  combo.setRenderer(new GenericListCellRenderer<>(new MultiButton(), new MultiButton()));
  hi.show();
}

private Map createListEntry(String name, String date) {
    Map entry = new HashMap<>();
    entry.put("Line1", name);
    entry.put("Line2", date);
    return entry;
}