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. */ import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.text.*; /** * TextInputDemo.java is a 1.4 application that uses * these additional files: * SpringUtilities.java * ... */ public class TextInputDemo extends JPanel implements ActionListener, FocusListener { JTextField streetField, cityField; JFormattedTextField zipField; JSpinner stateSpinner; boolean addressSet = false; Font regularFont, italicFont; JLabel addressDisplay; final static int GAP = 10; public TextInputDemo() { setLayout(new BoxLayout(this, BoxLayout.LINE_AXIS)); JPanel leftHalf = new JPanel() { //Don't allow us to stretch vertically. public Dimension getMaximumSize() { Dimension pref = getPreferredSize(); return new Dimension(Integer.MAX_VALUE, pref.height); } }; leftHalf.setLayout(new BoxLayout(leftHalf, BoxLayout.PAGE_AXIS)); leftHalf.add(createEntryFields()); leftHalf.add(createButtons()); add(leftHalf); add(createAddressDisplay()); } protected JComponent createButtons() { JPanel panel = new JPanel(new FlowLayout(FlowLayout.TRAILING)); JButton button = new JButton("Set address"); button.addActionListener(this); panel.add(button); button = new JButton("Clear address"); button.addActionListener(this); button.setActionCommand("clear"); panel.add(button); //Match the SpringLayout's gap, subtracting 5 to make //up for the default gap FlowLayout provides. panel.setBorder(BorderFactory.createEmptyBorder(0, 0, GAP - 5, GAP - 5)); return panel; } /** * Called when the user clicks the button or presses * Enter in a text field. */ public void actionPerformed(ActionEvent e) { if ("clear".equals(e.getActionCommand())) { addressSet = false; streetField.setText(""); cityField.setText(""); //We can't just setText on the formatted text //field, since its value will remain set. zipField.setValue(null); } else { addressSet = true; } updateDisplays(); } protected void updateDisplays() { addressDisplay.setText(formatAddress()); if (addressSet) { addressDisplay.setFont(regularFont); } else { addressDisplay.setFont(italicFont); } } protected JComponent createAddressDisplay() { JPanel panel = new JPanel(new BorderLayout()); addressDisplay = new JLabel(); addressDisplay.setHorizontalAlignment(JLabel.CENTER); regularFont = addressDisplay.getFont().deriveFont(Font.PLAIN, 16.0f); italicFont = regularFont.deriveFont(Font.ITALIC); updateDisplays(); //Lay out the panel. panel.setBorder(BorderFactory.createEmptyBorder(GAP / 2, //top 0, //left GAP / 2, //bottom 0)); //right panel.add(new JSeparator(JSeparator.VERTICAL), BorderLayout.LINE_START); panel.add(addressDisplay, BorderLayout.CENTER); panel.setPreferredSize(new Dimension(200, 150)); return panel; } protected String formatAddress() { if (!addressSet) return "No address set."; String street = streetField.getText(); String city = cityField.getText(); String state = (String) stateSpinner.getValue(); String zip = zipField.getText(); String empty = ""; if ((street == null) || empty.equals(street)) { street = "<em>(no street specified)</em>"; } if ((city == null) || empty.equals(city)) { city = "<em>(no city specified)</em>"; } if ((state == null) || empty.equals(state)) { state = "<em>(no state specified)</em>"; } else { int abbrevIndex = state.indexOf('(') + 1; state = state.substring(abbrevIndex, abbrevIndex + 2); } if ((zip == null) || empty.equals(zip)) { zip = ""; } StringBuffer sb = new StringBuffer(); sb.append("<html><p align=center>"); sb.append(street); sb.append("<br>"); sb.append(city); sb.append(" "); sb.append(state); //should format sb.append(" "); sb.append(zip); sb.append("</p></html>"); return sb.toString(); } //A convenience method for creating a MaskFormatter. protected MaskFormatter createFormatter(String s) { MaskFormatter formatter = null; try { formatter = new MaskFormatter(s); } catch (java.text.ParseException exc) { System.err.println("formatter is bad: " + exc.getMessage()); System.exit(-1); } return formatter; } /** * Called when one of the fields gets the focus so that * we can select the focused field. */ public void focusGained(FocusEvent e) { Component c = e.getComponent(); if (c instanceof JFormattedTextField) { selectItLater(c); } else if (c instanceof JTextField) { ((JTextField) c).selectAll(); } } //Workaround for formatted text field focus side effects. protected void selectItLater(Component c) { if (c instanceof JFormattedTextField) { final JFormattedTextField ftf = (JFormattedTextField) c; SwingUtilities.invokeLater(new Runnable() { public void run() { ftf.selectAll(); } }); } } //Needed for FocusListener interface. public void focusLost(FocusEvent e) { } //ignore protected JComponent createEntryFields() { JPanel panel = new JPanel(new SpringLayout()); String[] labelStrings = { "Street address: ", "City: ", "State: ", "Zip code: " }; JLabel[] labels = new JLabel[labelStrings.length]; JComponent[] fields = new JComponent[labelStrings.length]; int fieldNum = 0; //Create the text field and set it up. streetField = new JTextField(); streetField.setColumns(20); fields[fieldNum++] = streetField; cityField = new JTextField(); cityField.setColumns(20); fields[fieldNum++] = cityField; String[] stateStrings = getStateStrings(); stateSpinner = new JSpinner(new SpinnerListModel(stateStrings)); fields[fieldNum++] = stateSpinner; zipField = new JFormattedTextField(createFormatter("#####")); fields[fieldNum++] = zipField; //Associate label/field pairs, add everything, //and lay it out. for (int i = 0; i < labelStrings.length; i++) { labels[i] = new JLabel(labelStrings[i], JLabel.TRAILING); labels[i].setLabelFor(fields[i]); panel.add(labels[i]); panel.add(fields[i]); //Add listeners to each field. JTextField tf = null; if (fields[i] instanceof JSpinner) { tf = getTextField((JSpinner) fields[i]); } else { tf = (JTextField) fields[i]; } tf.addActionListener(this); tf.addFocusListener(this); } SpringUtilities.makeCompactGrid(panel, labelStrings.length, 2, GAP, GAP, //init x,y GAP, GAP / 2);//xpad, ypad return panel; } public String[] getStateStrings() { String[] stateStrings = { "Alabama (AL)", "Alaska (AK)", "Arizona (AZ)", "Arkansas (AR)", "California (CA)", "Colorado (CO)", "Connecticut (CT)", "Delaware (DE)", "District of Columbia (DC)", "Florida (FL)", "Georgia (GA)", "Hawaii (HI)", "Idaho (ID)", "Illinois (IL)", "Indiana (IN)", "Iowa (IA)", "Kansas (KS)", "Kentucky (KY)", "Louisiana (LA)", "Maine (ME)", "Maryland (MD)", "Massachusetts (MA)", "Michigan (MI)", "Minnesota (MN)", "Mississippi (MS)", "Missouri (MO)", "Montana (MT)", "Nebraska (NE)", "Nevada (NV)", "New Hampshire (NH)", "New Jersey (NJ)", "New Mexico (NM)", "New York (NY)", "North Carolina (NC)", "North Dakota (ND)", "Ohio (OH)", "Oklahoma (OK)", "Oregon (OR)", "Pennsylvania (PA)", "Rhode Island (RI)", "South Carolina (SC)", "South Dakota (SD)", "Tennessee (TN)", "Texas (TX)", "Utah (UT)", "Vermont (VT)", "Virginia (VA)", "Washington (WA)", "West Virginia (WV)", "Wisconsin (WI)", "Wyoming (WY)" }; return stateStrings; } public JFormattedTextField getTextField(JSpinner spinner) { JComponent editor = spinner.getEditor(); if (editor instanceof JSpinner.DefaultEditor) { return ((JSpinner.DefaultEditor) editor).getTextField(); } else { System.err.println("Unexpected editor type: " + spinner.getEditor().getClass() + " isn't a descendant of DefaultEditor"); return null; } } /** * 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("TextInputDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. JComponent newContentPane = new TextInputDemo(); newContentPane.setOpaque(true); //content panes must be opaque frame.setContentPane(newContentPane); //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); } }