In this topic, we will discuss TextListener in the AWT Interface.
The class which processes the TextEvent should implement this interface. The object of that class must be registered with a component. The object can be registered using the addTextListener() method.
Interface declaration
Following is the declaration for java.awt.event.TextListener interface:
public interface TextListener extends EventListener
Interface methods
| S.N. | Method & Description |
|---|---|
| 1 | void textValueChanged(TextEvent e)Invoked when the value of the text has changed. |
Methods inherited
This interface inherits methods from the following interfaces:
- java.awt.EventListener
TextListener Example
Create the following java program using any editor of your choice in say D:/ > AWT > com > adglob > gui >AwtListenerDemo.java
package com.adglob.gui;
import java.awt.*;
import java.awt.event.*;
public class AwtListenerDemo {
private Frame mainFrame;
private Label headerLabel;
private Label statusLabel;
private Panel controlPanel;
private TextField textField;
public AwtListenerDemo(){
prepareGUI();
}
public static void main(String[] args){
AwtListenerDemo awtListenerDemo = new AwtListenerDemo();
awtListenerDemo.showTextListenerDemo();
}
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 showTextListenerDemo(){
headerLabel.setText("Listener in action: TextListener");
textField = new TextField(10);
textField.addTextListener(new CustomTextListener());
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);
}
class CustomTextListener implements TextListener {
public void textValueChanged(TextEvent e) {
statusLabel.setText("Entered text: " + textField.getText());
}
}
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\adglob\gui\AwtListenerDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.adglob.gui.AwtListenerDemo
Verify the following output
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