RedGreenBorder.java Source code

Introduction

Here is the source code for RedGreenBorder.java

Source

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Insets;

import javax.swing.AbstractButton;
import javax.swing.ButtonModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.border.AbstractBorder;
import javax.swing.border.Border;

public class RedGreenBorder extends AbstractBorder {
    public boolean isBorderOpaque() {
        return true;
    }

    public Insets getBorderInsets(Component c) {
        return new Insets(3, 3, 3, 3);
    }

    public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) {
        Insets insets = getBorderInsets(c);
        Color horizontalColor;
        Color verticalColor;
        if (c.isEnabled()) {
            boolean pressed = false;
            if (c instanceof AbstractButton) {
                ButtonModel model = ((AbstractButton) c).getModel();
                pressed = model.isPressed();
            }
            if (pressed) {
                horizontalColor = Color.red;
                verticalColor = Color.green;
            } else {
                horizontalColor = Color.green;
                verticalColor = Color.red;
            }
        } else {
            horizontalColor = Color.lightGray;
            verticalColor = Color.lightGray;
        }
        g.setColor(horizontalColor);

        g.translate(x, y);

        // top
        g.fillRect(0, 0, width, insets.top);
        // bottom
        g.fillRect(0, height - insets.bottom, width, insets.bottom);

        g.setColor(verticalColor);
        // left
        g.fillRect(0, insets.top, insets.left, height - insets.top - insets.bottom);
        g.fillRect(width - insets.right, insets.top, insets.right, height - insets.top - insets.bottom);
        g.translate(-x, -y);
    }

    public static void main(String args[]) {
        JFrame frame = new JFrame("My Border");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Border border = new RedGreenBorder();
        JButton helloButton = new JButton("Hello");
        helloButton.setBorder(border);
        JButton braveButton = new JButton("Brave New");
        braveButton.setBorder(border);
        braveButton.setEnabled(false);
        JButton worldButton = new JButton("World");
        worldButton.setBorder(border);
        Container contentPane = frame.getContentPane();
        contentPane.add(helloButton, BorderLayout.NORTH);
        contentPane.add(braveButton, BorderLayout.CENTER);
        contentPane.add(worldButton, BorderLayout.SOUTH);
        frame.setSize(300, 100);
        frame.setVisible(true);
    }
}