The Java Developers Almanac 1.4


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Home > List of Packages > java.awt  [78 examples] > Focus  [16 examples]

e617. Determining the Opposite Component of a Focus Event

The opposite component is the other component affected in a focus event. Specifically, in a focus-lost event, the opposite component is the one gaining the focus. In a focus-gain event, the opposite component is the one losing the focus.

Sometimes the opposite component is null, which indicates that the component is in some other application.

    
component.addFocusListener(new MyFocusListener());
    
    public class MyFocusListener extends FocusAdapter {
        public void focusGained(FocusEvent evt) {
            // The component that lost the focus
            Component c = evt.getOppositeComponent();
        }
    
        public void focusLost(FocusEvent evt) {
            // The component that gained the focus
            Component c = evt.getOppositeComponent();
        }
    }

 Related Examples
e606. Determining Which Component or Window Has the Focus
e607. Preventing a Component from Gaining the Focus
e608. Preventing a Window from Gaining the Focus
e609. Listening to All Focus Changes Between Components in an Application
e610. Setting Focus Traversal Keys in a Component
e611. Setting Focus Traversal Keys for the Entire Application
e612. Moving the Focus to the Next or Previous Focusable Component
e613. Modifying the Focus Traversal Order
e614. Setting the Initial Focused Component in a Window
e615. Finding the Next Focusable Component
e616. Determining If a Focus Lost Is Temporary or Permanent
e618. Validating a JTextField When Permanently Losing the Focus
e619. Removing the Focus from the Application
e620. Activating a Keystroke When Any Component in the Window Has Focus
e621. Activating a Keystroke When Any Child Component Has Focus

See also: Colors    Components    Containers    Cursors    Drawing    Events    Frames    GridBagLayout    Images    Shapes    Simulating Events    Text    The Screen   


© 2002 Addison-Wesley.