|
The methods in JOptionPane
provide for a wide variety of basic dialogs. These can be warning
messages, confirmations, one line text inputs, and so forth. They
provide default icons to accompany the message or you supply your
own.
See the How
to Make Dialogs - Sun Java Tutorial and the JOptionPane
specification (for Java
5.0 Specs) for details of the many options for the showMessageDialog(),
showConfirmDialog(),
showInputDialog(),
and showOptionDialog()
overloaded versions of each. (For
each of these there is also a showInternalzzzzzDialog()
version for internal
frame interfaces.)
The applet below illustrates the essentials of these
four methods. Note that in most of the overridden verisions, the
first argument is a reference to a frame, which serves as the parent
to which the dialog belongs with regard to its modal behavior. If
this is set to null,
then a default frame is used.
DialogsApplet.java
|
import
javax.swing.*;
import java.awt.*;
import java.awt.event.*;
/**
* Generates various types of dialogs from options
in a JComboBox.
**/
public class DialogsApplet extends JApplet
implements ActionListener
{
String [] fDialogTypes =
{"Warning", "Confirm", "Message",
"Option", "Input"};
String fDialogType = "Warning";
String [] fOptions =
{"Red", "Orange", "Yellow", "Green",
"Blue"};
JComboBox fChoice;
JButton fButton;
/** Create an interface. **/
public void init () {
Container content_pane = getContentPane
();
// A panel to hold the fButton and
ComboBox.
JPanel panel_a = new JPanel (new GridLayout
(1,2));
// Create the interface to choose
a type of dialog
// and create it.
fButton = new JButton ("Make Dialog");
fButton.addActionListener (this);
fButton.setBackground (Color.RED);
panel_a.add (fButton);
fChoice = new JComboBox (fDialogTypes);
fChoice.addActionListener (this);
panel_a.add (fChoice);
// Use another panel to arrange the
first
// panel and a message at the bottom.
JPanel panel_b = new JPanel (new BorderLayout
());
panel_b.add ("Center", panel_a);
panel_b.add ("South",
new JLabel ("Generate
different types of dialogs",
JLabel.CENTER));
content_pane.add (panel_b);
} // init
/** React to actions of the fButton and combobox.
**/
public void actionPerformed (ActionEvent event)
{
// Use the type of component to find
where event
// came from.
Object source = event.getSource ();
if (source instanceof JButton) {
// Issue a
dialog according to the setting in the
// combobox.
if (fDialogType.equals
("Warning")) {
JOptionPane.showMessageDialog
(null,
"Put
a warning message here!", "A Warning Dialog",
JOptionPane.WARNING_MESSAGE);
} else if
(fDialogType.equals ("Confirm")) {
JOptionPane.showConfirmDialog
(null,
"Put
a confirmation message here", "A Confirm Dialog",
JOptionPane.YES_NO_CANCEL_OPTION);
} else if
(fDialogType.equals ("Message")) {
JOptionPane.showMessageDialog
(null,
"Put
a message here!", "A Message Dialog",
JOptionPane.PLAIN_MESSAGE);
} else if
(fDialogType.equals ("Option")) {
int
index =
JOptionPane.showOptionDialog
(null,
"Put
an options message here!", "An Options Dialog",
JOptionPane.DEFAULT_OPTION,
JOptionPane.ERROR_MESSAGE,
null,
fOptions, fOptions[0]);
if
(index == 0)
fButton.setBackground
(Color.RED);
else
if (index == 1)
fButton.setBackground
(Color.ORANGE);
else
if (index == 2)
fButton.setBackground
(Color.YELLOW);
else
if (index == 3)
fButton.setBackground
(Color.GREEN);
else
if (index == 4)
fButton.setBackground
(Color.BLUE);
} else
if (fDialogType.equals ("Input")) {
JOptionPane.showInputDialog
(null,
"User
input", "An Input Dialog",
JOptionPane.INFORMATION_MESSAGE);
}
} else {
fChoice
= (JComboBox)source;
fDialogType
= (String)fChoice.getSelectedItem ();
}
} // actionPerformed
} // class DialogsApplet
|
References & Web Resources
Latest update: Nov. 4, 2004
|
