G54PRG Programming
Lecture 23
GUI Programming II: Components
Amadeo Ascó
Adam Moore
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Previously
•
•
•
•
•
•
•
•
Hello World as GUI
Layout Design
Criteria In GUI
Human Interface Concepts
Requirements
Use Cases
User
actor
Design GUI
Java Foundation Classes
Amadeo Ascó , Adam Moore
Add record
View record
Edit record
Save record
Delete record
Database
actor
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Overview
• Hierarchy
• Overview Swing Components
• Swing Components
Amadeo Ascó , Adam Moore
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Hierarchy
java.lang
Object
java.awt
Component
Container
Abstract Window Toolkit
(AWT)
javax.swing
JComponent
JLabel
JMenuBar
JButton
JTextField
JPanel
JComboBox
JTable
Amadeo Ascó , Adam Moore
JCheckBox
JTextArea
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Swing Components
• Position  Layout Managers
• Look  how the control is displayed on the
screen
• Feel - base functionality
– Do you click on them. e.g. button (JButton)
– Do you type on them, e.g. text field (JTextField) ...
• Functionality Events
– What happen when the corresponding action has
been executed by the user, e.g. clicking on the
"Save" button save the data
Amadeo Ascó , Adam Moore
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Overview Swing Components
• JButton
• JCheckBox
• JComboBox
• JRadioButton
• JPanel
• JScrollBar
• JSlider
• JSplitPane
• JPopupMenu
Divider between panels
can be drag left and right
Amadeo Ascó , Adam Moore
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Swing Components
• JTree
• JMenuBar
•
•
•
•
•
JMenu
JMenuItem
JTextField
JTabbedPane
JTextArea
SubSuperClasses
bin
doc
readme.txt
javadoc
src
• JLabel
 Fix text on the display
Application title
Tab 1
Tab 2
Tab 3
Panel
• JDialog
• JTabel
Amadeo Ascó , Adam Moore
Data was saved.
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Swing Components
import javax.swing.JFrame;
import javax.swing.JLabel;
public class HelloWorldGUI extends JFrame {
public static void main(String[] args) {
new HelloWorldGUI();
} // main()
HelloWorldGUI() {
super("Hello World"); // the title
JLabel jlbHelloWorld = new JLabel(" Hello World!");
add(jlbHelloWorld); // add label to the GUI
setSize(150, 80); // size of the window
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true); // show the GUI
} // Constructor ()
} // end class HelloWorldGUI
Amadeo Ascó , Adam Moore
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Swing Components
• Extend JFrame to get the general look of a GUI
• JLabel corresponds to fix text to add to the GUI
Hello World
height
public class HelloWorldGUI extends JFrame {
...
HelloWorldGUI() {
super("Hello World"); // the title
JLabel jlbHelloWorld = new JLabel(" Hello World!");
width
add(jlbHelloWorld); // add label to the GUI
setSize(150, 80); // size of the window
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true); // show the GUI
} // Constructor ()
} // end class HelloWorldGUI
Amadeo Ascó , Adam Moore
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Swing Components
• Creating and Showing Simple Dialogs
– It is a accomplished by using the class JDialog
– Different ones depending of the message to display
– Default title and icon
JOptionPane.showMessageDialog(frame,
"Data was saved.", "Message");
– Custom title, warning icon
Data was saved.
Warning!
Data was saved.
JOptionPane.showMessageDialog(frame,
“Data was saved.", "Warning!", JOptionPane.WARNING_MESSAGE);
– Custom title, error icon
Error!
Data wasn’t saved.
JOptionPane.showMessageDialog(frame,
"Data wasn’t saved.", “Error!", JOptionPane.ERROR_MESSAGE);
Amadeo Ascó , Adam Moore
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Swing Components
• Yes/No dialog with default icon, custom title
int iAnswer = JOptionPane.showConfirmDialog(frame, "Would you like to
save the data?", "Question!", JOptionPane.YES_NO_OPTION);
Valid return values
• JOptionPane.YES_OPTION: user has selected 'YES'
• JOptionPane.NO_OPTION: user has selected 'NO'
• JOptionPane.CLOSED_OPTION: user closed the dialog window
explicitly, rather than by choosing a button inside the option pane
Question!
Would you like to save the data?
Amadeo Ascó , Adam Moore
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Swing Components
• JMenuBar and JMenuItem
//Create the menu bar
JMenuBar menuBar = new JMenuBar();
JMenuBar
//Build the first menu
JMenu menu = new JMenu("1st Menu");
JMenu
menuBar.add(menu); // add menu to menu bar
// Add menu items
JMenuItem menuItem = new JMenuItem("1st Option");
menuItem.addItemListener(this); // register the listener
menu.add(menuItem); // add item to a container
add(JMenu)
add(JMenuItem)
add(JMenu)
JMenuItem
addItemListener(ItemList
ener)
JFrame
setJMenuBar(JMenuBar)
menuItem = new JMenuItem("2nd Option");
menuItem.addItemListener(this); // register the listener
menu.add(menuItem); // add item to a container
...
jFrame.setJMenuBar(menuBar); // set menu bar
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Swing Components
• JTextField
JTextField jText = new JTextField(15);
...
add(jText); // add to a container
...
jText.getText(); // get text on the text fields
• JButton
JButton jButton = new JButton("OK");
jButton.setActionCommand ("OK"); // assign an action identifier
jButton.addActionListerner(this); // register the listener
add(jButton); // add to a container
...
Amadeo Ascó , Adam Moore
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Swing Components
• JTable
// Header
String[] astrColumnNames =
{"First name", "Last name", "Num",
"Road",
"Alive"};
Object[][] aoRows = {
{"Debby", "Smith",
new Integer(5), "Parliament", new Boolean(false)},
{"John", "Rainbow", new Integer(3), "Great Av.", new Boolean(true)},
{"Jason", "Wood",
new Integer(2), "Lower line", new Boolean(false)},
{"Jane", "White",
new Integer(13), "High Street", new Boolean(true)}
};
// Build table using these roes and column names
JTable table = new JTable(aoRows, astrColumnNames);
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References
A Brief Introduction to the Swing Package
http://download.oracle.com/javase/tutorial/ui/overview/index.html
Using Swing Components
http://download.oracle.com/javase/tutorial/uiswing/components/index.
html
Java API
http://download.oracle.com/javase/6/docs/api/
Course Resources Website
http://workspace.nottingham.ac.uk/display/G54ICP/Resources
Java look and feel Graphics Repository
http://java.sun.com/developer/techDocs/hi/repository/
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