import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.border.*; import java.applet.*; import java.net.*; /** Creating a custom dialog using JDialog.

* * Although the static methods in JOptionPane are convenient * and easy to use, they fall short if the goal is to * collect together several input parameters in a single dialog. For this, * you need to roll your own -- create a custom * dialog, by directly working with JDialog. *

* * This demo includes a custom class -- for convenience, * an inner class -- * that extends JDialog. The dialog is popped up from * the main application window to collect several input * parameters relating to the * properties of a displayed messages. The properties solicited for * input are the message font (i.e., family name, style, size), * the message text color, and the background color.

* The approach is much the same as with * JFileChooser where the dialog * class is first instantiated (without * showing the dialog), and then is popped up on an as-needed basis * using a "show" instance method on the dialog object. * After the user closes the dialog, the show * method returns an * int, indicating whether the dialog was * closed by clicking "OK" or "Cancel". Assuming the * user clicked "OK", the parameters inputted via the dialog are then * available to the main application using other instance methods.

* * The window for the custom dialog * presents a standard close button in the top right-hand * corner:

* *

* * This button presents an interesting UI issue: * What are the users' expectations if the dialog * is closed by clicking this button? Are the inputs * saved, or are they discarded? The "OK" button clearly suggests * that the inputs are saved and available to the application * upon closing the dialog. The "Cancel" button, on the otherhand, clearly * suggests the opposite; namely that the user's inputs are discarded. * To avoid uncertainty on the effect of clicking the dialog window's close * button, the button is disabled. The user must close the dialog either * by clicking "OK" or "Cancel".

* * JDialog, like JFrame, is a top-level container. * Not surprisingly, designing a JDialog is much the * same as designing a GUI application's main window, which is typically an * extended JFrame. Issues such as * installing listeners, implementing listener interfaces, navigation, * input validation, and component layout are pretty well the same.

* * There are some new issues to confront, however, such as initialization, * positioning, * making the dialog appear and disappear, and passing parameters back and * forth between the main application and the dialog. Let's discuss * a few of these. The constructor * for the dialog begins as follows:

* * 

*     CustomDialog(Frame owner)
*     {
*        super(owner, "Customize Message Properties", true);
*        this.setResizable(false);
*        this. setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
*        ...
*
* * The boolean ("true") passed to the superclass constructor makes the dialog * modal, effectively blocking the application thread until the dialog is * closed. We also make the dialog's size fixed and disable the close button, * as noted earlier.

* * We noted above * that parameters are passed from the dialog to the main application via * instance methods. That is, the main application invokes instance methods * on the dialog object to get the values inputted by the user. * Three instance method serve this purpose:

* * 

*     public Font getFont()
*     public Color getForeColor() 
*     public Color getBackColor() 
*
* * Passing parameters from the application to the dialog is often necessary * to initialize the dialog with current settings. * This is accomplished through arguments to the "show" method:

* * 

*     public int showCustomDialog(Frame f, Font fontArg, 
*           Color foreColorArg, Color backColorArg)
*
* * The Frame argument is simply a reference to the * calling application's window. Within the show method, it is used * to make sure the dialog pops up on top of the application window:

* * 

*        this.setLocationRelativeTo(f);
*
* * The remaining arguments are the message properties as they currently * exist within the application. The dialog is initialized to show * a message "Example" using the same properties. The dialog's widgets * are also initialized to reflect the * current settings. After initialization, the dialog is * popped up:

* * 

*     this.show();
*
* * The user makes changes by manipulating the widgest * and clicks "OK" or "Cancel" when finished. * Whithin the event handler for the OK and Cancel buttons, the dialog * is closed:

* * 

*     this.hide();
*
* * This effectively passes control back to the show method, which returns * one of the following integers to the application:

* * 

*     public static final int OK_OPTION = 0;
*     public static final int CANCEL_OPTION = 1;
*
* * For further detials, consult the source code or the API or tutorial * notes on JDialog.

* * Screen snap upon launch...
*

* * Screen snap showing "Customize Message Properties" dialog...
*

* * Screen snap showing dialog after a few changes...
*

* * @see source code * @author Scott MacKenzie, 2002 */ public class DemoCustomDialog { public static void main(String[] args) { // use look and feel for my system (Win32) try { UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName()); } catch (Exception e) {} DemoCustomDialogFrame frame = new DemoCustomDialogFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setTitle("DemoCustomDialog"); frame.pack(); frame.show(); } } class DemoCustomDialogFrame extends JFrame implements ActionListener { CustomDialog cd; JTextField messageField; JButton customize; JButton exit; String message; Font messageFont; Color foreColor; Color backColor; public DemoCustomDialogFrame() { // initialize message properties message = "Hello Java World"; messageFont = new Font("Arial", Font.PLAIN, 26); foreColor = Color.black; backColor = Color.white; // ---------------------------------- // construct and configure components // ---------------------------------- cd = new CustomDialog(this); messageField = new JTextField(); messageField.setPreferredSize(new Dimension(400, 200)); messageField.setEditable(false); messageField.setHorizontalAlignment(SwingConstants.CENTER); messageField.setAlignmentX(Component.CENTER_ALIGNMENT); messageField.setToolTipText("Right click to change message"); updateMessage(); customize = new JButton("Customize"); customize.setMaximumSize(customize.getPreferredSize()); customize.setAlignmentX(Component.CENTER_ALIGNMENT); exit = new JButton("Exit"); exit.setMaximumSize(customize.getPreferredSize()); exit.setAlignmentX(Component.CENTER_ALIGNMENT); // ------------- // add listeners // ------------- customize.addActionListener(this); exit.addActionListener(this); messageField.addMouseListener(new PopupListener()); // ----------------- // layout components // ----------------- // add components to panels JPanel p = new JPanel(); p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS)); p.add(customize); p.add(Box.createRigidArea(new Dimension(0, 25))); p.add(messageField); p.add(Box.createRigidArea(new Dimension(0, 25))); p.add(exit); p.setBorder(BorderFactory.createEmptyBorder(25, 25, 25, 25)); // make panel this JFrame's content pane this.setContentPane(p); } // -------------------------------- // implement ActionListener methods // -------------------------------- public void actionPerformed(ActionEvent ae) { Object source = ae.getSource(); if (source == customize) { // Pop up the custom dialog, and send the font and color // properties as arguments. The dialog will use these // as initial properties in the dialog. int i = cd.showCustomDialog(this, messageFont, foreColor, backColor); // The returned int indicates whether the user closed the dialog // by pressing the OK button or the Cancel button. If the OK // button was used, re-configure the message using the new // attibute values. These are retrieved using instance methods. if (i == CustomDialog.OK_OPTION) { messageFont = cd.getFont(); foreColor = cd.getForeColor(); backColor = cd.getBackColor(); updateMessage(); } } else if (source == exit) System.exit(0); } // ------------- // Other methods // ------------- public void updateMessage() { messageField.setText(message); messageField.setFont(messageFont); messageField.setForeground(foreColor); messageField.setBackground(backColor); } // ------------- // inner classes // ------------- private class PopupListener extends MouseAdapter { public void mousePressed(MouseEvent me) { String tmp = JOptionPane.showInputDialog(messageField, "Enter new message"); if (tmp != null && tmp.length() > 0) { message = tmp; updateMessage(); } } } /** Define a custom class for a dialog box to change the * message properties. */ private class CustomDialog extends JDialog implements ActionListener, ItemListener { public static final int OK_OPTION = 0; public static final int CANCEL_OPTION = 1; int userResponse; final String[] SZ = { "10", "14", "18", "22", "26", "32", "38", "48" }; JCheckBox italic; JCheckBox bold; JComboBox sizeCombo; JComboBox fontCombo; JTextField example; JButton ok; JButton cancel; JButton foreground; JButton background; CustomDialog(Frame owner) { super(owner, "Customize Message Properties", true); this.setResizable(false); this. setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE); GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); String[] fontList = ge.getAvailableFontFamilyNames(); fontCombo = new JComboBox(fontList); italic = new JCheckBox("Italic"); bold = new JCheckBox("Bold"); sizeCombo = new JComboBox(SZ); ((JLabel)sizeCombo.getRenderer()).setHorizontalAlignment(SwingConstants.CENTER); sizeCombo.setSelectedIndex(4); sizeCombo.setPreferredSize(new Dimension(45, 21)); // tweek size example = new JTextField(" Example "); example.setHorizontalAlignment(SwingConstants.CENTER); example.setFont(new Font("sanserif", Font.PLAIN, 28)); example.setEditable(false); ok = new JButton("OK"); cancel = new JButton("Cancel"); ok.setPreferredSize(cancel.getPreferredSize()); foreground = new JButton("Text"); background = new JButton("Background"); foreground.setPreferredSize(background.getPreferredSize()); // ------------- // add listeners // ------------- fontCombo.addActionListener(this); italic.addItemListener(this); bold.addItemListener(this); sizeCombo.addActionListener(this); ok.addActionListener(this); cancel.addActionListener(this); foreground.addActionListener(this); background.addActionListener(this); // ----------------- // layout components // ----------------- JPanel p0 = new JPanel(); p0.add(fontCombo); p0.setBorder(new TitledBorder(new EtchedBorder(), "Font family")); JPanel p1a = new JPanel(); p1a.add(italic); p1a.add(bold); p1a.setBorder(new TitledBorder(new EtchedBorder(), "Font style")); JPanel p1b = new JPanel(); p1b.add(sizeCombo); p1b.add(new JLabel("pt.")); p1b.setBorder(new TitledBorder(new EtchedBorder(), "Font size")); JPanel p1 = new JPanel(); p1.setLayout(new BoxLayout(p1, BoxLayout.X_AXIS)); p1.add(p1a); p1.add(p1b); p1.setAlignmentX(Component.CENTER_ALIGNMENT); JPanel p2 = new JPanel(); // use FlowLayout p2.add(foreground); p2.add(background); p2.setBorder(new TitledBorder(new EtchedBorder(), "Message color")); p2.setAlignmentX(Component.CENTER_ALIGNMENT); JPanel p3 = new JPanel(); p3.setLayout(new BoxLayout(p3, BoxLayout.Y_AXIS)); p3.add(example); p3.setPreferredSize(new Dimension(250, 60)); p3.setMaximumSize(new Dimension(250, 60)); p3.setAlignmentX(Component.CENTER_ALIGNMENT); JPanel p4 = new JPanel(); p4.add(ok); p4.add(cancel); p4.setAlignmentX(Component.CENTER_ALIGNMENT); JPanel p = new JPanel(); p.setLayout(new BoxLayout(p, BoxLayout.Y_AXIS)); p.add(p0); p.add(Box.createRigidArea(new Dimension(0, 10))); p.add(p1); p.add(Box.createRigidArea(new Dimension(0, 10))); p.add(p2); p.add(Box.createRigidArea(new Dimension(0, 10))); p.add(p3); p.add(Box.createRigidArea(new Dimension(0, 10))); p.add(p4); p.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10)); // tweek sizes of panels to make the dialog look nice Dimension d1 = p3.getPreferredSize(); Dimension d2 = p1.getPreferredSize(); p1.setPreferredSize(new Dimension(d1.width, d2.height)); p1.setMaximumSize(new Dimension(d1.width, d2.height)); d2 = p2.getPreferredSize(); p2.setPreferredSize(new Dimension(d1.width, d2.height)); p2.setMaximumSize(new Dimension(d1.width, d2.height)); this.setContentPane(p); this.pack(); } // ------------------------------- // implement ActionListener method // ------------------------------- public void actionPerformed(ActionEvent ae) { Object source = ae.getSource(); if (source == ok) { userResponse = OK_OPTION; this.hide(); } else if (source == cancel) { userResponse = CANCEL_OPTION; this.hide(); } else if (source == fontCombo) { JComboBox cb = (JComboBox)source; String s = (String)cb.getSelectedItem(); Font tmp = example.getFont(); example.setFont(new Font(s, tmp.getStyle(), tmp.getSize())); } else if (source == sizeCombo) { JComboBox cb = (JComboBox)source; String s = (String)cb.getSelectedItem(); int newSize = Integer.parseInt(s); Font tmp = example.getFont(); example.setFont(new Font(tmp.getFamily(), tmp.getStyle(), newSize)); } else if (source == foreground) { Color tmp = JColorChooser.showDialog(this, "Choose text color", example.getForeground()); if (tmp != null) example.setForeground(tmp); } else if (source == background) { Color tmp = JColorChooser.showDialog(this, "Choose background color", example.getBackground()); if (tmp != null) example.setBackground(tmp); } } // ----------------------------- // implement ItemListener method // ----------------------------- public void itemStateChanged(ItemEvent ie) { Object source = ie.getSource(); Font tmp = example.getFont(); int style = tmp.getStyle(); if (source == italic) if (italic.isSelected()) style = style | Font.ITALIC; // turn italic on else style = style & ~Font.ITALIC; // turn italic off else if (source == bold) if (bold.isSelected()) style = style | Font.BOLD; // turn bold on else style = style & ~Font.BOLD; // turn bold off example.setFont(new Font(tmp.getFamily(), style, tmp.getSize())); } // ------------- // other methods // ------------- public Font getFont() { return example.getFont(); } public Color getForeColor() { return example.getForeground(); } public Color getBackColor() { return example.getBackground(); } public int showCustomDialog(Frame f, Font fontArg, Color foreColorArg, Color backColorArg) { this.setLocationRelativeTo(f); // set the font combobox to the current font family name String s = fontArg.getName(); fontCombo.setSelectedItem((Object)s); // set the style checkboxes to the current font style int style = fontArg.getStyle(); if ((style & Font.ITALIC) == 0) italic.setSelected(false); else italic.setSelected(true); if ((style & Font.BOLD) == 0) bold.setSelected(false); else bold.setSelected(true); // set the size combobox to the current font size int size = fontArg.getSize(); sizeCombo.setSelectedItem((Object)("" + size)); // give the example text field the current message properties example.setFont(fontArg); example.setForeground(foreColorArg); example.setBackground(backColorArg); // show the dialog this.show(); // When the user closes the dialog by clicking "OK" or "Cancel", // return a pre-defined integer indicating which button was // pressed. return userResponse; } } }