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AWT FocusAdapter Class
Introduction
The class FocusAdapter is an abstract (adapter) class for receiving keyboard focus events. All methods of this class are empty. This class is convenience class for creating listener objects.
Class declaration
Following is the declaration for java.awt.event.FocusAdapter class:
public abstract class FocusAdapter extends Object implements FocusListener
Class constructors
S.N. | Constructor & Description |
---|---|
1 | FocusAdapter() |
Class methods
S.N. | Method & Description |
---|---|
1 | void focusGained(FocusEvent e) Invoked when a component gains the keyboard focus. |
2 | focusLost(FocusEvent e) Invoked when a component loses the keyboard focus. |
Methods inherited
This class inherits methods from the following classes:
java.lang.Object
FocusAdapter Example
Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtAdapterDemo.javapackage com.tutorialspoint.gui; import java.awt.*; import java.awt.event.*; public class AwtAdapterDemo { private Frame mainFrame; private Label headerLabel; private Label statusLabel; private Panel controlPanel; public AwtAdapterDemo(){ prepareGUI(); } public static void main(String[] args){ AwtAdapterDemo awtAdapterDemo = new AwtAdapterDemo(); awtAdapterDemo.showFocusAdapterDemo(); } private void prepareGUI(){ mainFrame = new Frame("Java AWT Examples"); mainFrame.setSize(400,400); mainFrame.setLayout(new GridLayout(3, 1)); mainFrame.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent windowEvent){ System.exit(0); } }); headerLabel = new Label(); headerLabel.setAlignment(Label.CENTER); statusLabel = new Label(); statusLabel.setAlignment(Label.CENTER); statusLabel.setSize(350,100); controlPanel = new Panel(); controlPanel.setLayout(new FlowLayout()); mainFrame.add(headerLabel); mainFrame.add(controlPanel); mainFrame.add(statusLabel); mainFrame.setVisible(true); } private void showFocusAdapterDemo(){ headerLabel.setText("Listener in action: FocusAdapter"); Button okButton = new Button("OK"); Button cancelButton = new Button("Cancel"); okButton.addFocusListener(new FocusAdapter(){ public void focusGained(FocusEvent e) { statusLabel.setText(statusLabel.getText() + e.getComponent().getClass().getSimpleName() + " gained focus. "); } }); cancelButton.addFocusListener(new FocusAdapter(){ public void focusLost(FocusEvent e) { statusLabel.setText(statusLabel.getText() + e.getComponent().getClass().getSimpleName() + " lost focus. "); } }); controlPanel.add(okButton); controlPanel.add(cancelButton); mainFrame.setVisible(true); } }
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtAdapterDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtAdapterDemo
Verify the following output
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