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AWT KeyAdapter Class
Introduction
The class KeyAdapter is an abstract (adapter) class for receiving keyboard 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.KeyAdapter class:
public abstract class KeyAdapter extends Object implements KeyListener
Class constructors
S.N. | Constructor & Description |
---|---|
1 | KeyAdapter() |
Class methods
S.N. | Method & Description |
---|---|
1 | void keyPressed(KeyEvent e) Invoked when a key has been pressed. |
2 | void keyReleased(KeyEvent e) Invoked when a key has been released. |
3 | void keyTyped(KeyEvent e) Invoked when a key has been typed. |
Methods inherited
This class inherits methods from the following classes:
java.lang.Object
KeyAdapter 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.showKeyAdapterDemo(); } 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 showKeyAdapterDemo(){ headerLabel.setText("Listener in action: KeyAdapter"); final TextField textField = new TextField(10); textField.addKeyListener(new KeyAdapter() { public void keyPressed(KeyEvent e) { if(e.getKeyCode() == KeyEvent.VK_ENTER){ statusLabel.setText("Entered text: " + textField.getText()); } } }); Button okButton = new Button("OK"); okButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { statusLabel.setText("Entered text: " + textField.getText()); } }); controlPanel.add(textField); controlPanel.add(okButton); 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