Java Doc for JComboBox.java in  » 6.0-JDK-Core » swing » javax » swing » Java Source Code / Java DocumentationJava Source Code and Java Documentation

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see java.beans.XMLEncoder .

See How to Use Combo Boxes in The Java Tutorial for further information.

See Also:   ComboBoxModel
See Also:   DefaultComboBoxModel
version:
   1.147 05/05/07
author:
   Arnaud Weber
author:
   Mark Davidson

Warning: Focus and keyboard navigation problems may arise if you add duplicate String objects.

Warning: If you subclass this do not create an anonymous inner class.

If anObject is not in the list and the combo box is uneditable, it will not change the current selection.

Refer to the table at Swing Components Supporting Action for a list of the properties this method sets.
Parameters:
  action - the Action associated with this combobox
Parameters:
  propertyName - the name of the property that changed
since:
   1.6
See Also:   Action
See Also:   JComboBox.configurePropertiesFromAction

The ActionListener will receive an ActionEvent when a selection has been made. If the combo box is editable, then an ActionEvent will be fired when editing has stopped.
Parameters:
  l - the ActionListener that is to be notified
See Also:   JComboBox.setSelectedItem

Warning: Focus and keyboard navigation problems may arise if you add duplicate String objects. A workaround is to add new objects instead of String objects and make sure that the toString() method is defined. For example:

 comboBox.addItem(makeObj("Item 1"));
 comboBox.addItem(makeObj("Item 1"));
 ...
 private Object makeObj(final String item)  {
 return new Object() { public String toString() { return item; } };
 }
 

aListener will receive one or two ItemEvents when the selected item changes.
Parameters:
  aListener - the ItemListener that is to be notified
See Also:   JComboBox.setSelectedItem

For all standard look and feels shipped with Java, the popup list portion of combo box is implemented as a JPopupMenu. A custom look and feel may not implement it this way and will therefore not receive the notification.
Parameters:
  l - the PopupMenuListener to add
since:
   1.4

Warning: If you subclass this do not create an anonymous inner class. If you do the lifetime of the combobox will be tied to that of the Action.
Parameters:
  a - the combobox's action
since:
   1.3
See Also:   Action
See Also:   JComboBox.setAction

This method is public but should not be called by anything other than the UI delegate.
See Also:   JComboBox.addPopupMenuListener
since:
   1.4

This method is public but should not be called by anything other than the UI delegate.
See Also:   JComboBox.addPopupMenuListener
since:
   1.4

This method is public but should not be called by anything other than the UI delegate.
See Also:   JComboBox.addPopupMenuListener
since:
   1.4

If the combo box is editable, then this value may not have been added to the combo box with addItem, insertItemAt or the data constructors. the current selected Object
See Also:   JComboBox.setSelectedItem

Setting the Action results in immediately changing all the properties described in Swing Components Supporting Action. Subsequently, the combobox's properties are automatically updated as the Action's properties change.

This method uses three other methods to set and help track the Action's property values. It uses the configurePropertiesFromAction method to immediately change the combobox's properties. To track changes in the Action's property values, this method registers the PropertyChangeListener returned by createActionPropertyChangeListener. The default PropertyChangeListener invokes the actionPropertyChanged method when a property in the Action changes.
Parameters:
  a - the Action for the JComboBox,or null.
since:
   1.3
See Also:   Action
See Also:   JComboBox.getAction
See Also:   JComboBox.configurePropertiesFromAction
See Also:   JComboBox.createActionPropertyChangeListener
See Also:   JComboBox.actionPropertyChanged
See Also:   

See the article Mixing Heavy and Light Components on The Swing Connection This method fires a property changed event.
Parameters:
  aFlag - if true, lightweight popups are desired

If a prototype display value is specified, the preferred size of the combo box is calculated by configuring the renderer with the prototype display value and obtaining its preferred size. Specifying the preferred display value is often useful when the combo box will be displaying large amounts of data. If no prototype display value has been specified, the renderer must be configured for each value from the model and its preferred size obtained, which can be relatively expensive.
Parameters:
  prototypeDisplayValue -
See Also:   JComboBox.getPrototypeDisplayValue
since:
   1.4

The default renderer displays a string or an icon. Other renderers can handle graphic images and composite items.

To display the selected item, aRenderer.getListCellRendererComponent is called, passing the list object and an index of -1.
Parameters:
  aRenderer - the ListCellRenderer thatdisplays the selected item
See Also:   JComboBox.setEditor

If anObject is not in the list and the combo box is uneditable, it will not change the current selection. For editable combo boxes, the selection will change to anObject.

If this constitutes a change in the selected item, ItemListeners added to the combo box will be notified with one or two ItemEvents. If there is a current selected item, an ItemEvent will be fired and the state change will be ItemEvent.DESELECTED. If anObject is in the list and is not currently selected then an ItemEvent will be fired and the state change will be ItemEvent.SELECTED.

ActionListeners added to the combo box will be notified with an ActionEvent when this method is called.
Parameters:
  anObject - the list object to select; use null toclear the selection