How to call in the paintScreen method in actionPerformed?

Question

So I've been tasked with adding 3 buttons of completely having the blinds open, having the button close the blind completely and close button. In the actionPerformed section I've tried calling the paintScreen method so that I can set the colour of the rectangle as cyan or grey but I've been finding it hard. Can you help and guide me to understanding how I could do this?

/**
 * A basic Java Swing application: a slider can be adjusted to open and close a "blind".
 */

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class WindowBlind extends JFrame 
                         implements ChangeListener, ActionListener {

    /**
     * A slider to adjust a "blind"
     */
    private JSlider slider;
    /**
     * To record the current slider/blind setting
     */
    private int sliderValue = 0;
    /**
     * For drawing on
     */
    private JPanel panel;    
    
   private JButton closeButton=new JButton("Close Program");  
  
  
    private JButton openBlindCompletely=new JButton("Open Blinds");  

    
    private JButton closeBlindCompletely=new JButton("Close Blinds");  

    /**
     * The main method launches the application
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        WindowBlind applic = new WindowBlind();
        applic.setLocation(100,100);
        applic.setVisible(true);
        
    }

    /**
     * Constructor - executed at instantiation of the class
     * Sets up the application's window
     */
    public WindowBlind() {
        
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        setTitle("WindowBlind");
        setSize(300,300);
        
        add(closeButton);
        add(openBlindCompletely);
        add(closeBlindCompletely);

        Container window = getContentPane();
        window.setLayout(new FlowLayout());     // The default is that JFrame uses BorderLayout

        panel = new JPanel() {
                    // This paintComponent overrides the default one in JPanel (which does nothing).
                    // paintComponent is called automatically when a screen refresh is needed.
                    // The screen (Graphics parameter g) has already been cleared before paintComponent is called
                    public void paintComponent(Graphics g) {
                        super.paintComponent(g); // Paint the panel's background
                        paintScreen(g);          // Now do our custom drawing
                    } // paintComponent
                };
        panel.setPreferredSize(new Dimension(200, 200));
        panel.setBackground(Color.white);
        window.add(panel);

        slider = new JSlider(JSlider.VERTICAL,0,100,0);
        slider.setInverted(true);               // 0 will be at top, not bottom, of vertical slider
        window.add(slider);
        slider.addChangeListener(this);         // Register for slider event
    } // constructor

    /**
     * Re-draws the window image: a "blind" covering a "window" through which the blue sky can be seen, referring to the global variable sliderValue to determine the blind size
     * @param g
     */
    public void paintScreen(Graphics g) {
        g.setColor(Color.cyan);
        g.fillRect(70, 40, 60, 100);         // The blue sky
        g.setColor(Color.lightGray);
        g.fillRect(70, 40, 60, sliderValue); // The blind, partially closed
        g.setColor(Color.black);
        g.drawRect(70, 40, 60, 100);   // The window frame
    
    } // paintScreen

    /**
     * When the slider is adjusted, this method is called automatically
     * @param e
     */
    public void stateChanged(ChangeEvent e) {
    sliderValue = slider.getValue();  // Fetch the slider's current setting
        repaint();                        // Force a screen refresh (paintComponent is called indirectly)
    } // stateChanged

    @Override
    public void actionPerformed(ActionEvent e) {

        if (e.getSource() == closeButton)
        {
            
        }
        
        if (e.getSource() == openBlindCompletely)
        {
            
        }
        
        if (e.getSource() == closeBlindCompletely)
        {

        }       
    }        
}

Answer 1

Add listeners for the buttons, something like:

        openBlindCompletely.addActionListener(this);

change the slider value, something like:

        if (e.getSource() == openBlindCompletely) {
            slider.setValue(slider.getMinimum());
        }