Java Swing How to - Perform some action BEFORE a JFrame is minimized








Question

We would like to know how to perform some action BEFORE a JFrame is minimized.

Answer

import java.awt.Dimension;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
//from  ww  w . j  av a 2  s .  c o  m
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main {

  public Main() {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel panel = new JPanel() {
      @Override
      public Dimension getPreferredSize() {
        return new Dimension(300, 300);
      }
    };
    frame.add(panel);
    frame.addWindowStateListener(new WindowAdapter() {
      @Override
      public void windowStateChanged(WindowEvent we) {
        super.windowStateChanged(we);
        if (we.getNewState() == Frame.ICONIFIED) {
          System.out.println("Here");
        }
      }
    });
    frame.pack();
    frame.setVisible(true);
  }

  public static void main(String[] args) {
    new Main();
  }
}