Java Algorithms How to - Draw random color

• Back to Random  ↑

Question

We would like to know how to draw random color.

Answer

import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
/*from www . j a  v a  2  s. c  o  m*/
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Main extends JFrame {
  int grid = 20;
  int pnlCnt = grid * grid;
  JFrame frame = new JFrame();
  JPanel[] panels = new JPanel[pnlCnt];
  Timer t;

  public Main() {
    for (int i = 0; i < panels.length; i++) {
      final String[] labels = new String[] { "0", "1" };
      final Random rand = new Random();
      int index = rand.nextInt(labels.length);
      String randomTitle = labels[index];
      final JLabel label = new JLabel(randomTitle, JLabel.CENTER);
      Timer lblt = new Timer(00, new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent ae) {
          label.setText(labels[rand.nextInt(labels.length)]);
        }
      });
      lblt.setRepeats(true);
      lblt.start();
      label.setForeground(Color.green);
      label.setVerticalAlignment(JLabel.CENTER);
      panels[i] = new JPanel();
      panels[i].setBackground(Color.BLACK);
      panels[i].add(label);
      frame.getContentPane().add(panels[i]);
    }
    frame.setLayout(new GridLayout(grid, grid));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setExtendedState(java.awt.Frame.MAXIMIZED_BOTH);
    frame.setVisible(true);

    ActionListener action = new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        for (int i = 0; i < panels.length; i++) {
          Color mix = new Color(255, 255, 255);
          Random random = new Random();
          int r = random.nextInt(255);
          int g = random.nextInt(255);
          int b = random.nextInt(255);

          if (mix != null) {
            r = (r + mix.getRed()) / 2;
            g = (g + mix.getGreen()) / 2;
            b = (b + mix.getBlue()) / 2;
          }
          Color color = new Color(r, g, b);
          panels[i].setBackground(color);
        }
      }
    };

    t = new Timer(00, action);
    t.setRepeats(true);
    t.start();
  }

  public static void main(String args[]) {
    new Main();
  }
}

• Back to Random  ↑