12 Basic Swing

7/14/2019 12 Basic Swing

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2010 Marty Hall

wBetter GUI Controls

Originals of Slides and Source Code for Examples:

http://courses.coreservlets.com/Course-Materials/java5.html

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2010 Marty Hall

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Topics in This Section

New features s.

Basic approach

Starting points JApplet, JFrame

Swing equivalent of AWT components JLabel, JButton, JPanel, JSlider

JColorChooser, JInternalFrame, JOptionPane, JToolBar,

JEditorPane er s mp e componen s

JCheckBox, JRadioButton, JTextField, JTextArea,JFileChooser

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2010 Marty Hall

Overview




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New Features vs AWT

Many more built-in controls Image buttons, tabbed panes, sliders, toolbars, color

choosers, HTML text areas, lists, trees, and tables.

Border styles, text alignments, and basic drawingfeatures. Images can be added to almost any control.

A pluggable look and feelNot limited to native look.

Built-in double buffering, tool-tips, dockable toolbars,

keyboard accelerators, custom cursors, etc.

Model-view-controller architectureCan change internal representation of trees, lists, tables.

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Swing vs. AWT Programming

Naming conventionAll Swing component names begin with a capital J and

follow the format JXxx. E.g., JFrame, JPanel, JApplet,JDialo JButton. Man are ust AWT names with a J.

Lightweight components

Most Swing components are lightweight: formed bydrawing in the underlying window.

Use of paintComponent for drawing us om raw ng co e s n pa n omponen , no pa n .

Double buffering turned on by default.

With Swing, you have to explicitly set the native look.

Don't mix Swing and AWT in same window7


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Classic Java Look and Feel

8 htt ://download. ava.net/ avadeskto /swin set3/Swin Set3. nl

New Java Look and Feel. . _

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Windows Look and Feel

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CDE/Motif Look and Feel

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Setting Native Look and Feel

IdeaMany apps use native look, not default Java look

Changing is tedious, so use static method

public class WindowUtilities {public static voidsetNativeLookAndFeel() {

UIManager.setLookAndFeel(

UIManager.getSystemLookAndFeelClassName());catch Exce tion eSystem.out.println("Error setting native LAF: "

+ e);

}...

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Nimbus Look and Feel

New ntro uce n . . _

Motivations

interfacesWindows LAF not updated to be consistent with Vista

Other LAFs did not scale well Nimbus based on vector graphics

e por a eStick with original Java LAF if Nimbus is unavailable

http://developers.sun.com/learning/javaoneonline/

2008/pdf/TS-6096.pdf13


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Setting Nimbus Look and Feel

public static void setNimbusLookAndFeel() {

LookAndFeelInfo[] lafs =

UIManager.getInstalledLookAndFeels();for LookAndFeelInfo laf: lafs

if ("Nimbus".equals(laf.getName())) {

UIManager.setLookAndFeel(laf.getClassName());

}

}

} catch(Exception e) {

System.out.println("Error setting Nimbus LAF: " + e);

}

}

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Whirlwind Tour of Basic

Starting points JApplet, JFrame

Swing equivalent of AWT components a e , utton, ane , er

New Swing components , , , ,

JEditorPane

Other simple components JCheckBox, JRadioButton, JTextField, JTextArea,

JFileChooser

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2010 Marty Hall

JApplet and JFrame



Starting Point 1: JApplet

Content paneA JApplet contains a content pane in which to add

components. Changing other properties like the layoutmana er back round color etc. also a lies to thecontent pane. Access the content pane throughgetContentPane.

ayou managerThe default layout manager is BorderLayout (as with

, .BorderLayout is really layout manager of content pane.

Look and feelThe default look and feel is Java, so you have to

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JApplet: Example Code

import java.awt.*;

*. .

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"));con en .a new u on u on ;

}

}

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WindowUtilities is a class I wrote: download it from the Web site.

The code for setNativeLookAndFeel was shown on an earlier slide.

Starting Point 2: JFrame

Content pane JFrame uses content pane in same way as does JApplet.

Auto-close behavior rames c ose automat ca y w en you c c on t e ose

button (unlike AWT Frames).

However, closing the last JFrame does not result in yourprogram exiting the Java application. To get this behavior,call setDefaultCloseOperation(EXIT_ON_CLOSE).

This permits the JFrame to close; however, you wont be able tocomp ete any ouse c ean ng as you m g t n t e n ow stener.So, you can still use an explicit exit listener as we did with Frame.

Look and feelThe default look and feel is Java (Metal)

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JFrame: Example Code

public class JFrameExample extends JFrame {ublic static void main Strin ar sJFrame frame = new JFrameExample("This is a test");

frame.setVisible(true);}

public JFrameExample(String title) {super(title);

.setSize(300, 100);Container content = getContentPane();content.setBackground(Color.WHITE);content.setLayout(new FlowLayout());content.add(new JButton("Button 1"));

content.add(new JButton("Button 2"));con en .a new u on u on ;setDefaultCloseOperation(EXIT_ON_CLOSE);

}20

2010 Marty Hall

Components (vs. AWT)




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Swing Equivalents of AWT

JLabelNew features: HTML content images, borders

JButton ew eatures: cons, a gnment, mnemon cs

JPanel

JSlider

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JLabel

Main new feature: HTML content If text is "...", it gets rendered as HTML

HTML labels only work in JDK 1.2.2 or later, or in. . .

In JDK 1.2 the label string must begin with , not

. It is case-insensitive in JDK 1.3 and 1.4. JLabel fonts are ignored if HTML is used. If you use

HTML, all font control must be performed by HTML.

, , .

Other HTML support is spotty. Be sure to test each HTML construct you use. Permitting

e user o en er ex a run me s as ng ortrouble.

Other new features: ima es borders23


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JLabel: Example Code

String labelText =" ""GRAY Text";

JLabel coloredLabel =, .

...labelText =" m >B>Bo < B> an I a c< I> Tex m >";

JLabel boldLabel =new JLabel(labelText, JLabel.CENTER);

labelText ="The Applied Physics Laboratory is..." +

"of the Johns Hopkins University." +"

" + ... "... /html>";

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JLabel: Example Output

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JButton

Main new feature: icons. reate an mage con y pass ng t e mage con

constructor a String representing a GIF or JPG file(animated GIFs are supported!). rom an app e , ca ge mage ge o e ase

normally, then pass resultant Image to ImageIcon.

2. Pass the ImageIcon to the JButton constructor. erna ve y, ca se con. n ac , ere are poss e

images (rollover images, images for when button isdepressed, etc.)

HTML content as with JLabel

Alignment: location of image with respect to text Mnemonics: keyboard accelerators that let you use Alt-

someChar to trigger the button.26

JButton: Example Codeimport java.awt.*;

*. .

public class JButtons extends JFrame {

JFrame frame = new JButtons();frame.setVisible(true);

public JButtons() {su er "Usin JButton"

WindowUtilities.setNativeLookAndFeel();setDefaultCloseOperation(EXIT_ON_CLOSE);Container content = etContentPane();content.setBackground(Color.WHITE);content.setLayout(new FlowLayout());

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JButton: Example Code

JButton button1 = new JButton("Java");.

ImageIcon cup = new ImageIcon("images/cup.gif");

JButton button2 = new JButton(cup);.

JButton button3 = new JButton("Java", cup);content.add(button3);

= " "button4.setHorizontalTextPosition

(SwingConstants.LEFT);content.add button4

pack();

}}

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JPanel

Main new feature: bordersCreate a Border object by calling

BorderFactory.createXxxBorder.

setBorder.

JPanel p = new JPanel();

. .

Other features:La out mana er settin s

Can pass the layout manager to the JPanel constructor

Setting preferred size ere s no anvas. you wan ane o ac e

Canvas, call setPreferredSize.

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Standard Borders

Static methods in BorderFactory createEmptyBorder(int top, int left, int bottom, int right)

Creates an EmptyBorder object that simply adds spacemar ins around the com onent.

createLineBorder(Color color)createLineBorder(Color color, int thickness)

-

createTitledBorder(String title)createTitledBorder(Border border, String title)

e or er s an e c e ne un ess you exp c y prov e aborder style in second constructor.

createEtchedBorder()createEtchedBorder(Color highlight, Color shadow)

Creates a etched line without the label

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JPanel: Example Codepublic class SixChoicePanel extends JPanel {

ublic SixChoicePanel Strin title Strin buttonLabels{super(new GridLayout(3, 2));setBackground(Color.LIGHT_GRAY);se Bor er Bor erFac ory.crea eT e Bor er e ;ButtonGroup group = new ButtonGroup();JRadioButton option;

= .for(int i=0; i


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JPanel: Example Output

Left window uses createLineBorder

Right window has three SixChoicePanels

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JSlider

Basic usepublic JSlider()

public JSlider(int orientation)

,

public JSlider(int min, int max, int initialValue)

ublic JSlider int orientation int min int maxint initialValue)

New features: tick marks and labels setMajorTickSpacing

setMinorTickSpacing

setPaintLabels (icons allowed as labels)

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JSlider: Example Code

JSlider slider1 = new JSlider();. ...

content.add(slider1, BorderLayout.NORTH);

JSlider slider2 = new JSlider();. ...

slider2.setMajorTickSpacing(20);slider2.setMinorTickSpacing(5);

content.add(slider2, BorderLayout.CENTER);JSlider slider3 = new JSlider();slider3.setBorder ...slider3.setMajorTickSpacing(20);

slider3.setMinorTickSpacing(5);slider3.setPaintTicks(true);slider3.setPaintLabels(true);content.add(slider3, BorderLayout.SOUTH);

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2010 Marty Hall

Were Not in AWT




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JColorChooser

OpenCall JColorChooser.showDialog

First argument: parent component

Third argument: initially-selected Color

Return valueSelected Color if OK chosen

null if Cancel chosen

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JColorChooser:

Button that lets you change color of window

public void actionPerformed(ActionEvent e) {Color bgColor= JColorChooser.showDialog

(this,

"Choose Background Color",getContentPane().getBackground());

if (bgColor != null)getContentPane().setBackground(bgColor);

}

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JColorChooser:

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Internal Frames

MDI: Multiple Document InterfaceProgram has one large desktop pane that holds all other

windows. The other windows can be iconifiedminimized and moved around within this deskto ane

but not moved outside the pane. Furthermore, minimizingthe desktop pane hides all the contained windows as well.

xamp es: croso ower o n , ore raw, or anJBuilder, and Allaire HomeSite

Swin Su ort for MDI JDesktopPane

Serves as a holder for the other windows.

JInternalFrame Acts mostly like a JFrame, except that it is constrained to

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Using JInternalFrame

Main constructorpublic JInternalFrame(String title,

boolean resizable,,

boolean maximizable,

boolean iconifiable

Other useful methodsmoveToFront

moveToBack

setSize (required!) se oca on requ re

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Internal Frames: Example Codeimport java.awt.*;

*. .

public class JInternalFrames extends JFrame {

JFrame frame = new JInternalFrames();frame.setVisible(true);

public JInternalFrames() {su er "Multi le Document Interface"

WindowUtilities.setNativeLookAndFeel();setDefaultCloseOperation(EXIT_ON_CLOSE);Container content = etContentPane();

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Internal Frames: Example Code

JDesktopPane desktop = new JDesktopPane();. . _

content.add(desktop, BorderLayout.CENTER);

setSize(450, 400);=

JInternalFrame frame= new JInternalFrame(("Internal Frame " + i),

frame.setLocation(i*50+10, i*50+10);frame.setSize(200, 150);frame.setBack round Color.WHITEdesktop.add(frame);

frame.moveToFront();frame.setVisible(true);}

}

}42

Internal Frames:

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JOptionPane

Very rich class with many options fordifferent types of dialog boxes.

Five main static methods pt on ane.s ow essage a og

Icon, message, OK button

JO tionPane.showConfirmDialo Icon, message, and buttons:

OK, OK/Cancel, Yes/No, or Yes/No/Cancel

. Icon, message, textfield or combo box, buttons

JOptionPane.showOptionDialog Icon, message, array of buttons or other components

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JOptionPane Message Dialogs

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JOptionPane Confirmation

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JToolBar

Acts mostly like a JPanel for buttons

Dockable: can be dragged and dropped

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JEditorPane

Acts somewhat like a text area

Can display HTML and, if HyperLinkListener

attached, can follow links

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Other Simple Swing

JCheckBoxNote uppercase B

(vs. Checkbox in AWT)

Use a ButtonGroup to

link radio buttons JTextField

Just like AWT TextField except that it does not act as apasswor e use asswor e or t at

JTextArea

you want scrolling

JFileChooser49


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2010 Marty Hall

Wrap-Up



More Info

Sun Java Tutorial http://java.sun.com/docs/books/tutorial/ui/features/components.html

Very useful summary of most Swing components

Gives code examples

This link forwards to a URL at

oracle.com, but the original

link is still valid.

Includes graphical table showing each

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Summary

Port simple AWT components to Swing byadding J to front of class name

Put custom drawing in paintComponent a super.pa nt omponent at eg nn ng un ess you turn

off double buffering

But you usually want either new (Nimbus) LAF or

native LAF

Frames and applets use content pane

Dont put anything directly in window os componen s suppor or ers cons

Many new components52

2010 Marty Hall

u

12 Basic Swing

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