CODEWITHSUNDEEP
javaswingcomponentspaintcomponent
Hydraxia
Hydraxia

Reputation: 81

Change a JComponent's attribute

I have a simple JPanel so far, and some basic elements like a string to display, a rectangle and a JButton, all on this panel. When I click with the mouse on this panel, I want the things that use the custom color 'rainbowColor' change their color to exactly that color ( the string and the rectangle ).

int red = 0;
int green = 255;
int blue = 0;
Color rainbowColor = new Color(red, green, blue);
boolean whichColor = true;

if (whichColor) { red = 255; blue = 0; whichColor = false; }
else { red = 0; blue = 255; whichColor = true; }

My 'TEXT' appears to be green all the time, no matter if I click my panel. At least this means the code works in some way. I still don't understand: the code says that 'whichColor' is set to true, so it should set 'red' to 255. Only the 'paintComponent { ... }' part is important ( my guess ) in this case. I really don't know what have I done wrong, thank you very much for helping me!

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



public class Menu extends JPanel {

       public void paintComponent(Graphics g) {

                int margin = 4;
                int red = 0;
                int green = 255;
                int blue = 0;
                Color rainbowColor = new Color(red, green, blue);
                boolean whichColor = true;

                if (whichColor) { red = 255; blue = 0; whichColor = false; }
                else { red = 0; blue = 255; whichColor = true; }

          super.paintComponent(g);
          Font customFont = new Font("Dialog", Font.BOLD, 20);
          g.setFont(customFont);
          g.setColor( new Color(0,0,0));
          g.drawString( "TEXT", 20, 30 );
//        randomiseColor(randomColor);
          g.setColor(rainbowColor);
          g.drawString( "TEXT", 22, 32 );
          g.drawRect(margin, margin, getWidth() - margin*2 - 1, getHeight() - margin*2 - 1);
       }

    }

public static class RandomColorOnClick implements MouseListener {

       public void mousePressed(MouseEvent evt) {
          Component source = (Component)evt.getSource();
          source.repaint(); 
       }

       public void mouseClicked(MouseEvent evt) { }
       public void mouseReleased(MouseEvent evt) { }
       public void mouseEntered(MouseEvent evt) { }
       public void mouseExited(MouseEvent evt) { }

    }

public static void main(String[] args){

    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();

    double width = screenSize.getWidth();
    double height = screenSize.getHeight();

    RandomColorOnClick colorListener = new RandomColorOnClick();    
    ButtonHandler listener = new ButtonHandler();

    Menu main_text = new Menu();
    JPanel main_content = new JPanel();
    JFrame main_window = new JFrame("Some random text");
    JButton main_exit_button = new JButton("Exit");

    main_content.addMouseListener(colorListener);

    main_window.setContentPane(main_content);
    main_window.setSize(800, 600);
    main_window.setLocation(((int)width / 2) - 400, ((int)height / 2) - 300);
    main_window.setVisible(true);
    main_window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    main_content.setLayout(new BorderLayout());
    main_content.add(main_text, BorderLayout.CENTER);

    main_exit_button.addActionListener(listener);




}

Upvotes: 0

Views: 233

Answers (2)

Mr. Noddy
Mr. Noddy

Reputation: 1590

You have not initialized colour object after changing values of red, blue, green variables. Get color object initialized again if you are changing values of red blue green variables...

Upvotes: 0

Madhawa Priyashantha
Madhawa Priyashantha

Reputation: 9872

there are 2 problems

1) you have create boolean whichColor=true; inside the paintComponent() method(); so every time it draw the graphics, it creates a whichcolor variable and it's always true.create it outside of paintcomponent method as a instance variable .

2) creating color variable before change the colors.you are creating color variable but you change color after that.so color variable remain unchanged. Color rainbowColor = new Color(red, green, blue); .that's why it's always green. you and move color creating line after the if-else condition .but you can declare it outside and change color instead of creating again and again.

here is an example ...

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

public class Menu extends JPanel {

    private boolean whichColor = true;
    private Color rainbowColor;

    public void paintComponent(Graphics g) {

        int margin = 4;
        int red = 0;
        int green = 255;
        int blue = 0;

        if (whichColor) {
            red = 255;
            blue = 0;
            whichColor = false;
        } else {
            red = 0;
            blue = 255;
            whichColor = true;
        }
        rainbowColor = new Color(red, green, blue);
        super.paintComponent(g);
        Font customFont = new Font("Dialog", Font.BOLD, 20);
        g.setFont(customFont);
        g.setColor(new Color(0, 0, 0));
        g.drawString("TEXT", 20, 30);
//        randomiseColor(randomColor);
        g.setColor(rainbowColor);
        System.out.println(rainbowColor);
        g.drawString("TEXT", 22, 32);
        g.drawRect(margin, margin, getWidth() - margin * 2 - 1, getHeight() - margin * 2 - 1);

    }

    public static void main(String[] args) {

        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();

        double width = screenSize.getWidth();
        double height = screenSize.getHeight();

        RandomColorOnClick colorListener = new RandomColorOnClick();
        ButtonHandler listener = new ButtonHandler();

        Menu main_text = new Menu();
        JPanel main_content = new JPanel();
        JFrame main_window = new JFrame("Some random text");
        JButton main_exit_button = new JButton("Exit");

        main_content.addMouseListener(colorListener);

        main_window.setContentPane(main_content);
        main_window.setSize(800, 600);
        main_window.setLocation(((int) width / 2) - 400, ((int) height / 2) - 300);
        main_window.setVisible(true);
        main_window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        main_content.setLayout(new BorderLayout());
        main_content.add(main_text, BorderLayout.CENTER);

        main_exit_button.addActionListener(listener);
    }

}

class RandomColorOnClick implements MouseListener {

    public void mousePressed(MouseEvent evt) {
        Component source = (Component) evt.getSource();
        source.repaint();
    }

    public void mouseClicked(MouseEvent evt) {
    }

    public void mouseReleased(MouseEvent evt) {
    }

    public void mouseEntered(MouseEvent evt) {
    }

    public void mouseExited(MouseEvent evt) {
    }

}

Upvotes: 1

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