Change the sizes of all the passed buttons to be the size of the largest one. : SwingUtilities « Swing « Java Tutorial

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/*
 * Copyright (C) 2001-2004 Colin Bell
 * colbell@users.sourceforge.net
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FontMetrics;
import java.awt.Frame;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.Window;
import java.awt.geom.Rectangle2D;
import java.beans.PropertyVetoException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.SwingUtilities;

/**
 * Common GUI utilities accessed via static methods.
 * 
 * @author <A HREF="mailto:colbell@users.sourceforge.net">Colin Bell</A>
 */
public class GUIUtils {


  /**
   * Change the sizes of all the passed buttons to be the size of the largest
   * one.
   * 
   * @param btns
   *          Array of buttons to eb resized.
   * 
   * @throws IllegalArgumentException
   *           If <TT>btns</TT> is <TT>null</TT>.
   */
  public static void setJButtonSizesTheSame(JButton[] btns) {
    if (btns == null) {
      throw new IllegalArgumentException("null JButton[] passed");
    }

    // Get the largest width and height
    final Dimension maxSize = new Dimension(0, 0);
    for (int i = 0; i < btns.length; ++i) {
      final JButton btn = btns[i];
      final FontMetrics fm = btn.getFontMetrics(btn.getFont());
      Rectangle2D bounds = fm.getStringBounds(btn.getText(), btn.getGraphics());
      int boundsHeight = (int) bounds.getHeight();
      int boundsWidth = (int) bounds.getWidth();
      maxSize.width = boundsWidth > maxSize.width ? boundsWidth : maxSize.width;
      maxSize.height = boundsHeight > maxSize.height ? boundsHeight : maxSize.height;
    }

    Insets insets = btns[0].getInsets();
    maxSize.width += insets.left + insets.right;
    maxSize.height += insets.top + insets.bottom;

    for (int i = 0; i < btns.length; ++i) {
      JButton btn = btns[i];
      btn.setPreferredSize(maxSize);
    }
  }
}