The Java Developers Almanac 1.4


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Home > List of Packages > javax.swing  [141 examples] > JComboBox  [12 examples]

e765. Listening for Changes to the Selected Item in a JComboBox Component

Item events are generated whenever the selected item changes. These events are generated even while the user is moving through items in the displayed popup menu. If the combobox is editable, this event does not indicate whether the new item is taken from the predefined list or not. If this information is necessary, see e766 Listening for Action Events from a JComboBox Component.
    // Create an editable combobox
    String[] items = {"item1", "item2"};
    JComboBox cb = new JComboBox(items);
    cb.setEditable(true);
    
    // Create and register listener
    MyItemListener actionListener = new MyItemListener();
    cb.addItemListener(actionListener);
    
    class MyItemListener implements ItemListener {
        // This method is called only if a new item has been selected.
        public void itemStateChanged(ItemEvent evt) {
            JComboBox cb = (JComboBox)evt.getSource();
    
            // Get the affected item
            Object item = evt.getItem();
    
            if (evt.getStateChange() == ItemEvent.SELECTED) {
                // Item was just selected
            } else if (evt.getStateChange() == ItemEvent.DESELECTED) {
                // Item is no longer selected
            }
        }
    }

 Related Examples
e756. Creating a JComboBox Component
e757. Getting and Setting the Selected Item in a JComboBox Component
e758. Getting the Items in a JComboBox Component
e759. Adding and Removing an Item in a JComboBox Component
e760. Selecting an Item in a JComboBox Component with Multiple Keystrokes
e761. Determining If the Menu of a JComboBox Component Is Visible
e762. Displaying the Menu in a JComboBox Component Using a Keystroke
e763. Displaying the Menu in a JComboBox Component Using a Keystroke If the Selected Item Is Not Unique
e764. Setting the Number of Visible Items in the Menu of a JComboBox Component
e766. Listening for Action Events from a JComboBox Component
e767. Determining When the Menu of a JComboBox Component Is Displayed

See also: Actions    JButton    JCheckBox    JDesktop and JInternalFrame    JFrame, JWindow, JDialog    JLabel    JList    JProgressBar    JRadioButton    JScrollPane    JSlider    JSpinner    JSplitPane    JTabbedPane    JToolBar    Keystrokes and Input Maps    Layout    Look and Feel    Menus    Progress Monitor    The Screen    Tool Tips    UI Default Values   


© 2002 Addison-Wesley.