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Uvod u Swing – Japplet – Jframe – Look and Feel – Jlabel – Jbutton – Jpanel – Jslider – JcolorChooser – interni frameovi – JoptionPane – Jtoolbar – JeditorPane – JcheckBox – JradioButton – JfileChooser – JtextField – JtextArea – Jlist – Jtree - ispis
Introductory Material
·
Introduction
& and Extended Table of Contents (This page)
o
Main New Features
o
Swing Availability
o
Getting More Info
o
Main Differences in Use
o
Mixing AWT and Swing Components
(don't!)
See the on-line Java 2 API or the books in the Swing/JFC section of http://www.apl.jhu.edu/~hall/java/Java-Books.html.
E.g. JFrame, JPanel, JApplet, JDialog, JButton, etc.
getContentPane().add
setContentPane
AWT components are always on top, and z-ordering problems catch you in many unexpected ways. Stick with the AWT or move completely to Swing.
Using Top-Level Containers
·
JApplet
o
General Info
o
Differences from Applet
o
Example
JApplet
inherits from Applet
init,
start,
stop, etc.
unchanged getContentPane,
or if you want to replace it with your container (e.g. a JPanel), use
setContentPane.
BorderLayout
(like Frame and
JFrame), not
FlowLayout
(like Applet).
This is really the layout manager of the content pane.
paintComponent,
not paint.
This simple example shows the steps required to get what you
would have in the AWT if you had a simple applet whose init method
did nothing but drop three buttons into the window.
import java.awt.*;
import javax.swing.*;
/** Tiny example showing the main differences in using
* JApplet instead of Applet: using the content pane,
* getting Java (Metal) look and feel by default, and * having BorderLayout be the default instead of FlowLayout. * 1998-99 Marty Hall, http://www.apl.jhu.edu/~hall/java/*/
public class JAppletExample extends JApplet { public void init() { WindowUtilities.setNativeLookAndFeel(); Container content = getContentPane(); content.setBackground(Color.white); content.setLayout(new FlowLayout()); content.add(new JButton("Button 1")); content.add(new JButton("Button 2")); content.add(new JButton("Button 3")); }}
import java.awt.*;
import javax.swing.*;
public class JAppletExample extends JApplet { public void init() {WindowUtilities.setNativeLookAndFeel();
Container content = getContentPane();
content.setBackground(Color.white); content.setLayout(new FlowLayout()); content.add(new JButton("Button 1")); content.add(new JButton("Button 2")); content.add(new JButton("Button 3")); }}
Note:
the setNativeLookAndFeel
code is presented in WindowUtilities.java.
--------------------------------------------------------------------------- WindowUtilities.java
import javax.swing.*;
import java.awt.*;
/** A few utilities that simplify using windows in Swing.
* 1998-99 Marty Hall, http://www.apl.jhu.edu/~hall/java/
*/
public class WindowUtilities {/** Tell system to use native look and feel, as in previous
* releases. Metal (Java) LAF is the default otherwise.
*/
public static void setNativeLookAndFeel() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch(Exception e) {
System.out.println("Error setting native LAF: " + e);
}
}
public static void setJavaLookAndFeel() {
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
} catch(Exception e) {
System.out.println("Error setting Java LAF: " + e);
}
}
public static void setMotifLookAndFeel() {
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
} catch(Exception e) {
System.out.println("Error setting Motif LAF: " + e);
}
}
/** A simplified way to see a JPanel or other Container.
* Pops up a JFrame with specified Container as the content pane.
*/
public static JFrame openInJFrame(Container content,
int width,
int height,
String title,
Color bgColor) {
JFrame frame = new JFrame(title);
frame.setBackground(bgColor);
content.setBackground(bgColor);
frame.setSize(width, height);
frame.setContentPane(content);
frame.addWindowListener(new ExitListener());
frame.setVisible(true);
return(frame);
}
/** Uses Color.white as the background color. */
public static JFrame openInJFrame(Container content,
int width,
int height,
String title) {
return(openInJFrame(content, width, height, title, Color.white));
}
/** Uses Color.white as the background color, and the
* name of the Container's class as the JFrame title.
*/
public static JFrame openInJFrame(Container content,
int width,
int height) {
return(openInJFrame(content, width, height,
content.getClass().getName(),
Color.white));
}
}
·
JFrame
o
General Info
o
Differences from Frame
o
Example
getContentPane,
or if you want to replace the content pane with your container (e.g. a
JPanel), use
setContentPane.
JFrames
close automatically when you click on the close button (unlike AWT Frames).
However, closing the last JFrame does not result in your program exiting Java.
So your "main" JFrame still
needs a WindowListener.
This shows the steps required to imitate what you would get
in the AWT if you popped up a simple Frame, set the
layout manager to FlowLayout,
and dropped three buttons into it.
import java.awt.*;
import javax.swing.*;
public class JFrameExample { public static void main(String[] args) { WindowUtilities.setNativeLookAndFeel(); JFrame f = new JFrame("This is a test"); f.setSize(400, 150);Container content = f.getContentPane();
content.setBackground(Color.white); content.setLayout(new FlowLayout()); content.add(new JButton("Button 1")); content.add(new JButton("Button 2")); content.add(new JButton("Button 3")); f.addWindowListener(new ExitListener()); f.setVisible(true); }}
Note: also requires WindowUtilities.java, shown earlier.
import java.awt.*;
import java.awt.event.*;
/** A listener that you attach to the top-level Frame or JFrame of
* your application, so quitting the frame exits the application.
* 1998-99 Marty Hall, http://www.apl.jhu.edu/~hall/java/
*/
public class ExitListener extends WindowAdapter {public void windowClosing(WindowEvent event) {
System.exit(0);
}
}
import java.awt.*;
import java.awt.event.*;
public class ExitListener extends WindowAdapter { public void windowClosing(WindowEvent event) { System.exit(0); }}
o
LAF Availability
o
Specifying Native LAF
o
Examples
JFrame (or
main), or in
init in a
JApplet.
getSystemLookAndFeelClassName
method of UIManager,
and pass result to UIManager.setLookAndFeel.
setLookAndFeel
throws an exception, this is a bit inconvenient, and you might want to make a
static method in a utility class called "setNativeLookAndFeel".
See example below in WindowUtilities.java.
Here are some utility functions that set the LAF to native,
Java (Metal), and Motif, respectively. Since I think that most users will expect
the native LAF, I almost always call setNativeLookAndFeel
at the beginning of Swing programs.
import javax.swing.*;
import java.awt.*;
public class WindowUtilities {public static void setNativeLookAndFeel() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch(Exception e) {
System.out.println("Error setting native LAF: " + e);
}
}
public static void setJavaLookAndFeel() {
try {
UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
} catch(Exception e) {
System.out.println("Error setting Java LAF: " + e);
}
}
public static void setMotifLookAndFeel() {
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
} catch(Exception e) {
System.out.println("Error setting Motif LAF: " + e);
}
}
...
}
Simple Swing Components
·
JLabel
o
Basics
o
New Features: Images, Borders, and
HTML Content
o
Example
In many cases, JLabel is used
exactly like Label: as a
way to display text. However, since a JLabel can
have an image instead of or in addition to the text, it is also frequently used
as a way to put an image in a display.
A JLabel has three major features that Label does not.
The first is the ability to display images,
usually by supplying an ImageIcon
eiher to the constructor or via a call to setIcon. The
use of icons in JLabel is just
like the use in JButton, so
see the Swing
Tutorial JButton section for more details and code examples. For a quick
preview, however, see the third JLabel in the
example below.
The second new feature is the ability to place
borders around the labels. The use of borders is covered in the Swing
tutorial section on JPanel. For a quick preview, however, see the following
examples which use titled borders.
The third new feature, and the one I am focusing on here, is the ability to
use HTML to format the label. The idea is that, if the string for the label
begins with "<html>", then the string is interpreted as HTML rather than
taken literally. This lets you make multi-line labels, labels with mixed colors
and fonts, and various other fancy effects. This capability also applies to
JButton.
Although nice, this capabillity also has several significant limitations:
setIcon or
supply an ImageIcon to
the JLabel
constructor (as with the third label in the example shown above); the HTML
cannot have an IMG tag.
· JLabel label = new JLabel("<html>Bold Text");
· label.setFont(new Font("Serif", Font.PLAIN, 36));
...
Sun
says that this will probably not be fixed until after the first release of JDK
1.3.
JLabel or
JButton
works like <BR> does in "real" HTML, starting a new line but not leaving
a blank line in between.
------------------------------------
-------------------------------------
The following example produces the result shown in the image
above:
import java.awt.*;
import javax.swing.*;
public class JLabels extends JFrame {public static void main(String[] args) {
new JLabels();
}
public JLabels() {
super("Using HTML in JLabels");
WindowUtilities.setNativeLookAndFeel();
addWindowListener(new ExitListener());
Container content = getContentPane();
Font font = new Font("Serif", Font.PLAIN, 30);
content.setFont(font);
String labelText =
"<html><FONT COLOR=RED>Red</FONT> and " +
"<FONT COLOR=BLUE>Blue</FONT> Text</html>";
JLabel coloredLabel =
new JLabel(labelText, JLabel.CENTER);
coloredLabel.setBorder
(BorderFactory.createTitledBorder("Mixed Colors"));
content.add(coloredLabel, BorderLayout.NORTH);
labelText =
"<html><B>Bold</B> and <I>Italic</I> Text</html>";
JLabel boldLabel =
new JLabel(labelText, JLabel.CENTER);
boldLabel.setBorder
(BorderFactory.createTitledBorder("Mixed Fonts"));
content.add(boldLabel, BorderLayout.CENTER);
labelText =
"<html>The Applied Physics Laboratory is a division " +
"of the Johns Hopkins University." +
"<P>" +
"Major JHU divisions include:" +
"<UL>" +
" <LI>The Applied Physics Laboratory" +
" <LI>The Krieger School of Arts and Sciences" +
" <LI>The Whiting School of Engineering" +
" <LI>The School of Medicine" +
" <LI>The School of Public Health" +
" <LI>The School of Nursing" +
" <LI>The Peabody Institute" +
" <LI>The Nitze School of Advanced International Studies" +
"</UL>";
JLabel fancyLabel =
new JLabel(labelText,
new ImageIcon("images/JHUAPL.gif"),
JLabel.CENTER);
fancyLabel.setBorder
(BorderFactory.createTitledBorder("Multi-line HTML"));
content.add(fancyLabel, BorderLayout.SOUTH);
pack();
setVisible(true);
}
}
Note: also
requires WindowUtilities.java
and ExitListener.java,
shown earlier, plus JHUAPL.gif.
·
JButton
o
Basics
o
New Features: Icons, Alignment,
Mnemonics, and HTML Content
o
Example
·
JPanel
o
Basics
o
New Features: Borders
o
Example
·
JSlider
o
Basics
o
New Features: Tick Marks and
Labels
o
Example
o
Basics
Example
Simple Swing Components, continued
o
Basics
o
Example
o
Basics
o
Confirm Dialog Examples
o
Message Dialog Examples
o
Interactive Dialog Creator
·
JToolBar
o
Basics
o
Making Buttons for Toolbars
o
Example
o
Basics: Displaying HTML
o
Following Hypertext Links
o
Building A Simple Web Browser
o
HTML Support and JavaHelp
o
JLabel
o
JCheckBox
o
JRadioButton
o
JFileChooser
o
JTextField
o
JTextArea
Complex Swing Components
·
JList
o
General Info on MVC, Custom Data
Models, and Custom Cell Renderers
o
JList with Fixed Set of Choices
o
JList with Changeable Choices
o
JList with Custom Data Model
o
JList with Custom Renderer
·
JTree
o
Basic JTree
o
Handling JTree Events
o
Custom Models and Dynamic JTrees
o
Changing the Node Icons
Other Swing Capabilities
·
Printing
o
Background
o
Printing Basics
o
The Role of Double Buffering
o
A
General-Purpose Component-Printing Routine
Example
