JComboBox : Java Glossary

The name is misleading. JComboBox does not let you select combinations of options, the way you can with a JList, just a single option. The combo-moniker comes from the fact it has a combination write in field and select from pre-existing choices.

To control how the new write-in field possibility is keyed, you can write a custom ComboBoxEditor based on BasicComboBoxEditor.

JComboBox uses setSelectedItem instead of select. getSelectedItem returns an Object you must cast to a String. The use of Objects for your choices allows more flexibility in rendering the choices.

Gotchas

• Beware of the JComboBox(Vector<?>) constructor. It does not simply make a copy of the Vector. Any changes you make to the JComboBox model will also modify that Vector.
• JComboBox.setSelectedItem will trigger an ActionEvent that is immediately dispatched, even before your event handler completes. This is almost never what you want. You usually need to create some mechanism to ignore the event. Otherwise you can get a situation I call fibrillation where events trigger events in an uncontrolled way.

Keying enums with JComboBox

Here is how to let the user select an enum in a GUI (Graphic User Interface) using JComboBox.

Use

Here is how to use a JComboBox with simple Strings as the possible choices.

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