Java tutorial
/* From http://java.sun.com/docs/books/tutorial/index.html */ /* * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * -Redistribution of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * -Redistribution in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of Sun Microsystems, Inc. or the names of contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * This software is provided "AS IS," without a warranty of any kind. ALL * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that this software is not designed, licensed or intended * for use in the design, construction, operation or maintenance of any * nuclear facility. */ /* * A 1.4 application that uses SpringLayout to create a single row of * components, similar to that produced by a horizontal BoxLayout. Other files * required: SpringUtilities.java. */ import java.awt.Component; import java.awt.Container; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.Spring; import javax.swing.SpringLayout; public class SpringBox { /** * Create the GUI and show it. For thread safety, this method should be * invoked from the event-dispatching thread. */ private static void createAndShowGUI() { //Make sure we have nice window decorations. JFrame.setDefaultLookAndFeelDecorated(true); //Create and set up the window. JFrame frame = new JFrame("SpringBox"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Set up the content pane. Container contentPane = frame.getContentPane(); contentPane.setLayout(new SpringLayout()); //Add the buttons. contentPane.add(new JButton("Button 1")); contentPane.add(new JButton("Button 2")); contentPane.add(new JButton("Button 3")); contentPane.add(new JButton("Long-Named Button 4")); contentPane.add(new JButton("5")); //Lay out the buttons in one row and as many columns //as necessary, with 6 pixels of padding all around. SpringUtilities.makeCompactGrid(contentPane, 1, contentPane.getComponentCount(), 6, 6, 6, 6); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } } /** * A 1.4 file that provides utility methods for creating form- or grid-style * layouts with SpringLayout. These utilities are used by several programs, such * as SpringBox and SpringCompactGrid. */ class SpringUtilities { /** * A debugging utility that prints to stdout the component's minimum, * preferred, and maximum sizes. */ public static void printSizes(Component c) { System.out.println("minimumSize = " + c.getMinimumSize()); System.out.println("preferredSize = " + c.getPreferredSize()); System.out.println("maximumSize = " + c.getMaximumSize()); } /** * Aligns the first <code>rows</code>*<code>cols</code> components of * <code>parent</code> in a grid. Each component is as big as the maximum * preferred width and height of the components. The parent is made just big * enough to fit them all. * * @param rows * number of rows * @param cols * number of columns * @param initialX * x location to start the grid at * @param initialY * y location to start the grid at * @param xPad * x padding between cells * @param yPad * y padding between cells */ public static void makeGrid(Container parent, int rows, int cols, int initialX, int initialY, int xPad, int yPad) { SpringLayout layout; try { layout = (SpringLayout) parent.getLayout(); } catch (ClassCastException exc) { System.err.println("The first argument to makeGrid must use SpringLayout."); return; } Spring xPadSpring = Spring.constant(xPad); Spring yPadSpring = Spring.constant(yPad); Spring initialXSpring = Spring.constant(initialX); Spring initialYSpring = Spring.constant(initialY); int max = rows * cols; //Calculate Springs that are the max of the width/height so that all //cells have the same size. Spring maxWidthSpring = layout.getConstraints(parent.getComponent(0)).getWidth(); Spring maxHeightSpring = layout.getConstraints(parent.getComponent(0)).getWidth(); for (int i = 1; i < max; i++) { SpringLayout.Constraints cons = layout.getConstraints(parent.getComponent(i)); maxWidthSpring = Spring.max(maxWidthSpring, cons.getWidth()); maxHeightSpring = Spring.max(maxHeightSpring, cons.getHeight()); } //Apply the new width/height Spring. This forces all the //components to have the same size. for (int i = 0; i < max; i++) { SpringLayout.Constraints cons = layout.getConstraints(parent.getComponent(i)); cons.setWidth(maxWidthSpring); cons.setHeight(maxHeightSpring); } //Then adjust the x/y constraints of all the cells so that they //are aligned in a grid. SpringLayout.Constraints lastCons = null; SpringLayout.Constraints lastRowCons = null; for (int i = 0; i < max; i++) { SpringLayout.Constraints cons = layout.getConstraints(parent.getComponent(i)); if (i % cols == 0) { //start of new row lastRowCons = lastCons; cons.setX(initialXSpring); } else { //x position depends on previous component cons.setX(Spring.sum(lastCons.getConstraint(SpringLayout.EAST), xPadSpring)); } if (i / cols == 0) { //first row cons.setY(initialYSpring); } else { //y position depends on previous row cons.setY(Spring.sum(lastRowCons.getConstraint(SpringLayout.SOUTH), yPadSpring)); } lastCons = cons; } //Set the parent's size. SpringLayout.Constraints pCons = layout.getConstraints(parent); pCons.setConstraint(SpringLayout.SOUTH, Spring.sum(Spring.constant(yPad), lastCons.getConstraint(SpringLayout.SOUTH))); pCons.setConstraint(SpringLayout.EAST, Spring.sum(Spring.constant(xPad), lastCons.getConstraint(SpringLayout.EAST))); } /* Used by makeCompactGrid. */ private static SpringLayout.Constraints getConstraintsForCell(int row, int col, Container parent, int cols) { SpringLayout layout = (SpringLayout) parent.getLayout(); Component c = parent.getComponent(row * cols + col); return layout.getConstraints(c); } /** * Aligns the first <code>rows</code>*<code>cols</code> components of * <code>parent</code> in a grid. Each component in a column is as wide as * the maximum preferred width of the components in that column; height is * similarly determined for each row. The parent is made just big enough to * fit them all. * * @param rows * number of rows * @param cols * number of columns * @param initialX * x location to start the grid at * @param initialY * y location to start the grid at * @param xPad * x padding between cells * @param yPad * y padding between cells */ public static void makeCompactGrid(Container parent, int rows, int cols, int initialX, int initialY, int xPad, int yPad) { SpringLayout layout; try { layout = (SpringLayout) parent.getLayout(); } catch (ClassCastException exc) { System.err.println("The first argument to makeCompactGrid must use SpringLayout."); return; } //Align all cells in each column and make them the same width. Spring x = Spring.constant(initialX); for (int c = 0; c < cols; c++) { Spring width = Spring.constant(0); for (int r = 0; r < rows; r++) { width = Spring.max(width, getConstraintsForCell(r, c, parent, cols).getWidth()); } for (int r = 0; r < rows; r++) { SpringLayout.Constraints constraints = getConstraintsForCell(r, c, parent, cols); constraints.setX(x); constraints.setWidth(width); } x = Spring.sum(x, Spring.sum(width, Spring.constant(xPad))); } //Align all cells in each row and make them the same height. Spring y = Spring.constant(initialY); for (int r = 0; r < rows; r++) { Spring height = Spring.constant(0); for (int c = 0; c < cols; c++) { height = Spring.max(height, getConstraintsForCell(r, c, parent, cols).getHeight()); } for (int c = 0; c < cols; c++) { SpringLayout.Constraints constraints = getConstraintsForCell(r, c, parent, cols); constraints.setY(y); constraints.setHeight(height); } y = Spring.sum(y, Spring.sum(height, Spring.constant(yPad))); } //Set the parent's size. SpringLayout.Constraints pCons = layout.getConstraints(parent); pCons.setConstraint(SpringLayout.SOUTH, y); pCons.setConstraint(SpringLayout.EAST, x); } }