CODEWITHSUNDEEP
javaswinggraphicskeylistenerpaintcomponent
Ryel
Ryel

Reputation: 87

Random Color Background

I am trying to get this code to change the background color to a random color when I press 'r'. So far everything is working ok other than changing the background color to a random color. This program is a screen saver that I have to generate random shapes in random positions with random colors. 

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

public class ScreenSaver1 extends JPanel {
    private JFrame frame = new JFrame("FullSize");
    private Rectangle rectangle;
    boolean full;

    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        setBackground(Color.BLACK);
    }

    ScreenSaver1() {
        // Remove the title bar, min, max, close stuff
        frame.setUndecorated(true);
        // Add a Key Listener to the frame
        frame.addKeyListener(new KeyHandler());
        // Add this panel object to the frame
        frame.add(this);
        // Get the dimensions of the screen
        rectangle = GraphicsEnvironment.getLocalGraphicsEnvironment()
        .getDefaultScreenDevice().getDefaultConfiguration().getBounds();
        // Set the size of the frame to the size of the screen
        frame.setSize(rectangle.width, rectangle.height);
        frame.setVisible(true);
        // Remember that we are currently at full size
        full = true;
    }

// This method will run when any key is pressed in the window
class KeyHandler extends KeyAdapter {
    public void keyPressed(KeyEvent e) {
        // Terminate the program.
        if (e.getKeyChar() == 'x') {
            System.out.println("Exiting");
            System.exit(0);
        }
        else if (e.getKeyChar() == 'r') {
            System.out.println("Change background color");
            setBackground(new Color((int)Math.random() * 256, (int)Math.random() * 256, (int)Math.random() * 256));
        }
        else if (e.getKeyChar() == 'z') {
            System.out.println("Resizing");
            frame.setSize((int)rectangle.getWidth() / 2, (int)rectangle.getHeight());
        }
    }

}

public static void main(String[] args) {
        ScreenSaver1 obj = new ScreenSaver1();
    }
}

Upvotes: 0

Views: 3440

Answers (2)

sameer saxena
sameer saxena

Reputation: 33

Try this:

(int)(Math.random() * 256)

Or this:

Random gen= new Random();
getContentPane().setBackground(Color.Black);

To get random colors, try this:

.setBackground(Color.(gen.nextInt(256), gen.nextInt(256),
                gen.nextInt(256));

Upvotes: 0

MadProgrammer
MadProgrammer

Reputation: 347214

I would start by removing setBackground(Color.BLACK); from your paintComponent method

The other problem you're having is with the way you are calculating your random values...

(int)Math.random() * 256

This is basically casting the result of Math.random() to an int, which will, typically, result in it becoming 0, before it's multiplied by 256, which is 0...

Instead, try using something like

(int)(Math.random() * 256)

Which will perform the calculation of Math.random() * 256 before casting the result to int

You may also want to take a look at Frame#getExtendedState and Frame#setExtendedState...it will make your life considerably eaiser...

Upvotes: 4

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