How do I get my key listener to create a rectangle?

Question

This is my code. I want the key listener to create a rectangle when I press a key. I am having trouble implementing the fill rectangle method into the key listener.

I've tried to separate the key listener, but then, I don't know how to connect them to each other to use the JPanel methods.

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

public class Keyboard
{
    public static void main(String[] args)
    {
        JFrame frame = new JFrame("Keyboard");
        frame.setLayout(new BorderLayout());
        MyPanel displayPanel = new MyPanel();
        frame.add(displayPanel, BorderLayout.CENTER);

        frame.addKeyListener(displayPanel);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().width, java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().height);
        frame.setVisible(true);
    }
}

MyPanel class

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

import javax.swing.JPanel;

public class MyPanel extends JPanel implements KeyListener {
    private boolean one;
    private boolean two;
    private boolean three;
    private boolean four;
    private boolean five;
    private boolean six;
    private boolean seven;
    private boolean eight;
    private boolean nine;
    private boolean zero;
    private boolean dash;

    public MyPanel() {
        one = false;
        two = false;
        three = false;
        four = false;
        five = false;
        six = false;
        seven = false;
        eight = false;
        nine = false;
        zero = false;
        dash = false;

    }
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        setBackground(new Color(51, 25, 0));

        for(int i=0; i<11; i++)
        {
            if(i%2 == 0)
            {
                g.setColor(Color.WHITE);
                g.fillRect(i*(java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().width/11), 450, 212, 1000);   
            }
            else
            {
                g.setColor(Color.BLACK);
                g.fillRect(i*(java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().width/11), 450, 174, 1000);   
            }
            if(one==true)
            {
                g.setColor(Color.BLUE);
                g.fillRect(50,50,50,50);
                repaint();
            }
        }
    }
    public void keyPressed(KeyEvent e)
    {
        if(e.getKeyCode() ==KeyEvent.VK_1 && !one)
        {
            System.out.println("asdasda");
            one = true; 
        }
        else if(e.getKeyCode() ==KeyEvent.VK_2 && !two)
        {   
            two = true; 
        }
        else if(e.getKeyCode() ==KeyEvent.VK_3 && !three)
        {   
            three = true;   
        }
        else if(e.getKeyCode() ==KeyEvent.VK_4 && !four)
        {
            four = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_5 && !five)
        {
            five = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_6 && !six)
        {
            six = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_7 && !seven)
        {
            seven = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_8 && !eight)
        {
            eight = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_9 && !nine)
        {
            nine = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_0 && !zero)
        {
            zero = true;
        }
        else if(e.getKeyCode() == 189 && !dash)
        {
            dash = true;
        }
    }
    public void keyReleased(KeyEvent e)
    {
        if(e.getKeyCode() ==KeyEvent.VK_1)
        {
            one = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_2)
        {
            two = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_3)
        {
            three = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_4)
        {
            four = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_5)
        {
            five = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_6)
        {
            six = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_7)
        {
            seven = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_8)
        {
            eight = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_9)
        {
            nine = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_0)
        {
            zero = false;
        }
        else if(e.getKeyCode() == 189)
        {
            dash = false;
        }
    }
    public void keyTyped(KeyEvent e)
    {
        System.out.println("Typed: " + e.getKeyChar());
    }
}

Answer 1

I had a similar problem a while ago, I fixed it by creating a small rectangle class like this

package notDeafult;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * 
 */
public class rectangle {
//The basic outline of a rectangle making up the grid

    Rectangle rect;
    int width;
    int height;

    public rectangle() {
    }

    public rectangle(int x, int y) {

        this.width = 80; //Setting the size
        this.height = 80;
        this.rect = new Rectangle(x + 80, y + 30, width, height);//Moving the object to the centre 
    }

    public void draw(Graphics g) {
        g.setColor(Color.green);
        //.drawRect only draws the outline
        g.drawRect(rect.x, rect.y, width, height);

    }

}

Then when you're ready simply call a paint method under a new Jpanel, like this:

jPanel3 = new javax.swing.JPanel(){
    public void paintComponent(Graphics g) {
                super.paintComponent(g);
                rectangle rect = new rectangle(width, height);
                rect.draw(g)



 }

And then you could just give the paintComponent its own method name like paintRectangles or something

and call it here when you get your key press

else if(e.getKeyCode() ==KeyEvent.VK_5){
            paintRectangles();
}

Something like that should work, I think.

Answer 2

I did some changes in your class:

• is not needed to init all boolean variables to false, those are its values yet
• created a paintRectangle method
• Eclipse code formatting (I think is more clear)

---

public class MyPanel extends JPanel implements KeyListener {

    private boolean one, two, three, four, five, six, seven, eight, nine, zero, dash;

    public MyPanel() {
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        setBackground(new Color(51, 25, 0));

        for (int i = 0; i < 11; i++) {
            if (i % 2 == 0) {
                g.setColor(Color.WHITE);
                g.fillRect(
                        i * (java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().width
                                / 11),
                        450, 212, 1000);
            } else {
                g.setColor(Color.BLACK);
                g.fillRect(
                        i * (java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().width
                                / 11),
                        450, 174, 1000);
            }

        }

        paintRectangle(g);
    }

    private void paintRectangle(Graphics g) {
        if (one) {
            g.setColor(Color.BLUE);
            g.fillRect(50, 50, 50, 50);
        } else if (two) {
            g.setColor(Color.CYAN);
            g.fillRect(50, 50, 50, 50);
        }
    }

    public void keyPressed(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_1 && !one) {
            System.out.println("asdasda");
            one = true;
            repaint();
        } else if (e.getKeyCode() == KeyEvent.VK_2 && !two) {
            two = true;
            repaint();
        } else if (e.getKeyCode() == KeyEvent.VK_3 && !three) {
            three = true;
        } else if (e.getKeyCode() == KeyEvent.VK_4 && !four) {
            four = true;
        } else if (e.getKeyCode() == KeyEvent.VK_5 && !five) {
            five = true;
        } else if (e.getKeyCode() == KeyEvent.VK_6 && !six) {
            six = true;
        } else if (e.getKeyCode() == KeyEvent.VK_7 && !seven) {
            seven = true;
        } else if (e.getKeyCode() == KeyEvent.VK_8 && !eight) {
            eight = true;
        } else if (e.getKeyCode() == KeyEvent.VK_9 && !nine) {
            nine = true;
        } else if (e.getKeyCode() == KeyEvent.VK_0 && !zero) {
            zero = true;
        } else if (e.getKeyCode() == 189 && !dash) {
            dash = true;
        }
    }

    public void keyReleased(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_1) {
            one = false;
        } else if (e.getKeyCode() == KeyEvent.VK_2) {
            two = false;
        } else if (e.getKeyCode() == KeyEvent.VK_3) {
            three = false;
        } else if (e.getKeyCode() == KeyEvent.VK_4) {
            four = false;
        } else if (e.getKeyCode() == KeyEvent.VK_5) {
            five = false;
        } else if (e.getKeyCode() == KeyEvent.VK_6) {
            six = false;
        } else if (e.getKeyCode() == KeyEvent.VK_7) {
            seven = false;
        } else if (e.getKeyCode() == KeyEvent.VK_8) {
            eight = false;
        } else if (e.getKeyCode() == KeyEvent.VK_9) {
            nine = false;
        } else if (e.getKeyCode() == KeyEvent.VK_0) {
            zero = false;
        } else if (e.getKeyCode() == 189) {
            dash = false;
        }
    }

    public void keyTyped(KeyEvent e) {
        System.out.println("Typed: " + e.getKeyChar());
    }
}

Answer 3

I figured out the problem. Here is the code for your problem.

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

    public class Keyboard
    {
        public static void main(String[] args)
        {
            JFrame frame = new JFrame("Keyboard");
            frame.setLayout(new BorderLayout());
            MyPanel displayPanel = new MyPanel();
            frame.add(displayPanel, BorderLayout.CENTER);

            frame.addKeyListener(displayPanel);

            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setSize(java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().width, java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().height);
            frame.setVisible(true);
        }
    }

Here is MyPanel Class

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.awt.image.ImageObserver;
import java.text.AttributedCharacterIterator;
import javax.swing.JComponent;

import javax.swing.JPanel;

public class MyPanel extends JPanel implements KeyListener {
    private boolean one;
    private boolean two;
    private boolean three;
    private boolean four;
    private boolean five;
    private boolean six;
    private boolean seven;
    private boolean eight;
    private boolean nine;
    private boolean zero;
    private boolean dash;
    Graphics g;

    public MyPanel() {
        one = false;
        two = false;
        three = false;
        four = false;
        five = false;
        six = false;
        seven = false;
        eight = false;
        nine = false;
        zero = false;
        dash = false;

    }
    @Override
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        setBackground(new Color(51, 25, 0));

        for(int i=0; i<11; i++)
        {
            if(i%2 == 0)
            {
                g.setColor(Color.WHITE);
                g.fillRect(i*(java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().width/11), 450, 212, 1000);   

            }
            else
            {
                g.setColor(Color.BLACK);
                g.fillRect(i*(java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getMaximumWindowBounds().width/11), 450, 174, 1000);   
            }
            if(one==true)
            {

                g.setColor(Color.BLUE);
                g.drawRect(50, 50, 50, 50);
                g.fillRect(50,50,50,50);
                repaint();

            }

        }
    }
    @Override
    public void keyPressed(KeyEvent e)
    {
        if(e.getKeyCode() ==KeyEvent.VK_1)
        {

                one = true; 
                repaint();
            System.out.println("asdasda");


        }
        else if(e.getKeyCode() ==KeyEvent.VK_2 && !two)
        {   
            two = true; 
        }
        else if(e.getKeyCode() ==KeyEvent.VK_3 && !three)
        {   
            three = true;   
        }
        else if(e.getKeyCode() ==KeyEvent.VK_4 && !four)
        {
            four = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_5 && !five)
        {
            five = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_6 && !six)
        {
            six = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_7 && !seven)
        {
            seven = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_8 && !eight)
        {
            eight = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_9 && !nine)
        {
            nine = true;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_0 && !zero)
        {
            zero = true;
        }
        else if(e.getKeyCode() == 189 && !dash)
        {
            dash = true;
        }
    }
    public void keyReleased(KeyEvent e)
    {
        if(e.getKeyCode() ==KeyEvent.VK_1)
        {
            one = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_2)
        {
            two = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_3)
        {
            three = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_4)
        {
            four = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_5)
        {
            five = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_6)
        {
            six = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_7)
        {
            seven = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_8)
        {
            eight = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_9)
        {
            nine = false;
        }
        else if(e.getKeyCode() ==KeyEvent.VK_0)
        {
            zero = false;
        }
        else if(e.getKeyCode() == 189)
        {
            dash = false;
        }
    }
    public void keyTyped(KeyEvent e)
    {
        System.out.println("Typed: " + e.getKeyChar());
    }
}

The reason your code is not working is that you did not calling repaint() method after setting one = true; . Now your code is working. Check and let me know if there is any confusion.

Note: This only works for Key 1. Now do similar for other Keys.