With this simple tutorial we are going to see how to implement a simple key listener for your Java Desktop Application. This is a very nice tool if your application offers rich keyboard activity to the user.
In short, in order to implement a simple key listener in Java, one should perform these steps:
- Create a new
KeyAdapterinstance. - Override the
keyPressedmethod to customize the handling of that specific event. Now every time the user presses a key this method will be launched. - Use
KeyEvent.getKeyChar()andKeyEvent.getKeyCode()to find out which key the user pressed.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.desktop;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Frame;
import java.awt.TextArea;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
public class KeyListener {
public static void main(String[] args) {
// Create frame with specific title
Frame frame = new Frame("Example Frame");
// Create a component to add to the frame; in this case a text area with sample text
Component textArea = new TextArea("You pressed []: n");
textArea.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent evt) {
TextArea source = (TextArea)evt.getSource();
source.setText("You pressed [" + evt.getKeyText(evt.getKeyCode()) +"] : ");
}
});
// Add the components to the frame; by default, the frame has a border layout
frame.add(textArea, BorderLayout.NORTH);
// Show the frame
int width = 300;
int height = 300;
frame.setSize(width, height);
frame.setVisible(true);
}
}
This was an example on how to handle key presses in Java.
