import java.awt.Color;
import javax.swing.JLayeredPane;

public class LayeredFrame_Correct extends javax.swing.JFrame {
    
    private final Color[] colors = new Color[]{Color.BLUE, Color.PINK, Color.GREEN, Color.YELLOW, Color.CYAN, Color.WHITE};
    private int colorIndex;

    /** Creates new form LayeredFrame */
    public LayeredFrame_Correct() {
        initComponents();
        setTitle("Correct Manual Code");
        colorIndex = 0;
    }
    
    private Color getNextColor() {
        if (colorIndex < colors.length - 1) {
            colorIndex++;
        }
        else {
            colorIndex = 0;
        }
        return colors[colorIndex];
    }

    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    private void initComponents() {

        layeredPane = new javax.swing.JLayeredPane();
        lowerPanel = new javax.swing.JPanel();
        colorButton = new javax.swing.JButton();
        upperPanel = new javax.swing.JPanel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        lowerPanel.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0), 2));
        // Call setLayer() BEFORE adding component to JLayeredPane
        // This is optional, since objects are added at DEFAULT_LAYER unless otherwise specified
        layeredPane.setLayer(lowerPanel, JLayeredPane.DEFAULT_LAYER);   
        layeredPane.add(lowerPanel);
        lowerPanel.setBounds(10, 10, 380, 280);

        colorButton.setText("Change Color");
        colorButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                changeLowerPanelBackground(evt);
            }
        });
        layeredPane.add(colorButton);
        colorButton.setBounds(140, 330, 120, 25);

        upperPanel.setBorder(javax.swing.BorderFactory.createLineBorder(java.awt.Color.red, 2));
        // Call setLayer() BEFORE adding component to JLayeredPane
        layeredPane.setLayer(upperPanel, JLayeredPane.MODAL_LAYER);
        layeredPane.add(upperPanel);
        upperPanel.setBounds(10, 10, 380, 140);

        getContentPane().add(layeredPane, java.awt.BorderLayout.CENTER);

        setBounds(0, 0, 418, 440);
    }

    private void changeLowerPanelBackground(java.awt.event.ActionEvent evt) {                                            
        Color nextColor = getNextColor();
        lowerPanel.setBackground(nextColor);
        lowerPanel.repaint();
    }                                           

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new LayeredFrame_Correct().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton colorButton;
    private javax.swing.JLayeredPane layeredPane;
    private javax.swing.JPanel lowerPanel;
    private javax.swing.JPanel upperPanel;
    // End of variables declaration                   

}