Java Swing How to - Extend JButton to create arrow button

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Question

We would like to know how to extend JButton to create arrow button.

Answer

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Insets;
//from w w  w .j  a  v a  2  s .co  m
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.SwingConstants;

public class Main {
  public static void main(final String args[]) {
    ArrowButton button = new ArrowButton(SwingConstants.EAST, 1, 30);

    JOptionPane.showMessageDialog(null, button);

    button.doClick();
  }
}

/**
 * A button which paints on it one or more scaled arrows in one of the cardinal
 * directions.
 * 
 * @author Adrian BER
 */
class ArrowButton extends JButton {

  /** The cardinal direction of the arrow(s). */
  private int direction;

  /** The number of arrows. */
  private int arrowCount;

  /** The arrow size. */
  private int arrowSize;

  public ArrowButton(int direction, int arrowCount, int arrowSize) {
    setMargin(new Insets(0, 2, 0, 2));
    setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
    this.direction = direction;
    this.arrowCount = arrowCount;
    this.arrowSize = arrowSize;
  }

  /**
   * Returns the cardinal direction of the arrow(s).
   * 
   * @see #setDirection(int)
   */
  public int getDirection() {
    return direction;
  }

  /**
   * Sets the cardinal direction of the arrow(s).
   * 
   * @param direction
   *          the direction of the arrow(s), can be SwingConstants.NORTH,
   *          SwingConstants.SOUTH, SwingConstants.WEST or SwingConstants.EAST
   * @see #getDirection()
   */
  public void setDirection(int direction) {
    this.direction = direction;
  }

  /** Returns the number of arrows. */
  public int getArrowCount() {
    return arrowCount;
  }

  /** Sets the number of arrows. */
  public void setArrowCount(int arrowCount) {
    this.arrowCount = arrowCount;
  }

  /** Returns the arrow size. */
  public int getArrowSize() {
    return arrowSize;
  }

  /** Sets the arrow size. */
  public void setArrowSize(int arrowSize) {
    this.arrowSize = arrowSize;
  }

  public Dimension getPreferredSize() {
    return getMinimumSize();
  }

  public Dimension getMinimumSize() {
    return new Dimension(
        arrowSize
            * (direction == SwingConstants.EAST
                || direction == SwingConstants.WEST ? arrowCount : 3)
            + getBorder().getBorderInsets(this).left
            + getBorder().getBorderInsets(this).right, arrowSize
            * (direction == SwingConstants.NORTH
                || direction == SwingConstants.SOUTH ? arrowCount : 3)
            + getBorder().getBorderInsets(this).top
            + getBorder().getBorderInsets(this).bottom);
  }

  public Dimension getMaximumSize() {
    return getMinimumSize();
  }

  protected void paintComponent(Graphics g) {
    // this will paint the background
    super.paintComponent(g);

    Color oldColor = g.getColor();
    g.setColor(isEnabled() ? getForeground() : getForeground().brighter());

    // paint the arrows
    int w = getSize().width;
    int h = getSize().height;
    for (int i = 0; i < arrowCount; i++) {
      paintArrow(g, (w - arrowSize
          * (direction == SwingConstants.EAST
              || direction == SwingConstants.WEST ? arrowCount : 1))
          / 2
          + arrowSize
          * (direction == SwingConstants.EAST
              || direction == SwingConstants.WEST ? i : 0), (h - arrowSize
          * (direction == SwingConstants.EAST
              || direction == SwingConstants.WEST ? 1 : arrowCount))
          / 2
          + arrowSize
          * (direction == SwingConstants.EAST
              || direction == SwingConstants.WEST ? 0 : i), g.getColor());
    }

    g.setColor(oldColor);
  }

  private void paintArrow(Graphics g, int x, int y, Color highlight) {
    int mid, i, j;

    Color oldColor = g.getColor();
    boolean isEnabled = isEnabled();

    j = 0;
    arrowSize = Math.max(arrowSize, 2);
    mid = (arrowSize / 2) - 1;

    g.translate(x, y);

    switch (direction) {
    case NORTH:
      for (i = 0; i < arrowSize; i++) {
        g.drawLine(mid - i, i, mid + i, i);
      }
      if (!isEnabled) {
        g.setColor(highlight);
        g.drawLine(mid - i + 2, i, mid + i, i);
      }
      break;
    case SOUTH:
      if (!isEnabled) {
        g.translate(1, 1);
        g.setColor(highlight);
        for (i = arrowSize - 1; i >= 0; i--) {
          g.drawLine(mid - i, j, mid + i, j);
          j++;
        }
        g.translate(-1, -1);
        g.setColor(oldColor);
      }
      j = 0;
      for (i = arrowSize - 1; i >= 0; i--) {
        g.drawLine(mid - i, j, mid + i, j);
        j++;
      }
      break;
    case WEST:
      for (i = 0; i < arrowSize; i++) {
        g.drawLine(i, mid - i, i, mid + i);
      }
      if (!isEnabled) {
        g.setColor(highlight);
        g.drawLine(i, mid - i + 2, i, mid + i);
      }
      break;
    case EAST:
      if (!isEnabled) {
        g.translate(1, 1);
        g.setColor(highlight);
        for (i = arrowSize - 1; i >= 0; i--) {
          g.drawLine(j, mid - i, j, mid + i);
          j++;
        }
        g.translate(-1, -1);
        g.setColor(oldColor);
      }
      j = 0;
      for (i = arrowSize - 1; i >= 0; i--) {
        g.drawLine(j, mid - i, j, mid + i);
        j++;
      }
      break;
    }

    g.translate(-x, -y);
    g.setColor(oldColor);
  }
}

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