1. A Quick Java Swing Tutorial

2. Introduction Swing – A set of GUI classes Highlights
Part of the Java's standard library
Much better than the previous library: AWT
Abstract Window Toolkit
Highlights
A rich set of widgets
Widget: Any GUI element (also called: components)
Contents and shape are separated (MVC support)‏
Fine-grained control over the behavior and look and feel
Platform independent
Isolates the programmer from the operating system's GUI

3. Swing Components Containers Contain and manage other components.
Top Level/Internal
Examples: JFrame (Top Level), JScrollPane, JPanel.
Basic controls
Atomic components
Used for showing ouput and/or getting some input
Inherits JComponent
Examples: JButton, JLabel, JTextArea, JTable, Jlist
Usually every Swing class extends the corresponding AWT class
For backward-compatibility reasons

4. Anatomy of an Application GUI
Internal structure
JFrame
JFrame
JPanel
containers
JPanel
JButton
JButton
JLabel
JLabel

5. Build from bottom up Create: Add: (bottom up) Frame Panel Components
Listeners
Add: (bottom up)
listeners into components
components into panel
panel into frame
Listener
JButton
JLabel
JPanel
JFrame

6. Top Level Containers: JFrame
javax.swing.JFrame:
Top-level window with a title and a border.
Usually used as a program's main window 6 6

7. Application Code import javax.swing.*; class hello {
public static void main(String[] args){
JFrame f = new JFrame(“title”);
JPanel p = new JPanel();
JButton b = new JButton(“press me”);
p.add(b); // add button to panel
f.setContentPane(p); // add panel to frame
f.show(); }
press me

8. Top Level Containers: JDialog
javax.swing.JDialog:
More simple and limited than frames
Typically used for showing a short message on the screen
Also has a border and a title bar
May have an owner
If the owner is invisible the dialog will also be invisible
Use the static method of JoptionPane to show standard dialog boxes: JOptionPane.showMessageDialog(null, "4+2=6");

9. JOptionPane examples 2
showConfirmDialog analogous to a System.out.print that prints a question, then reading an input value from the user (can only be one of the provided choices)
import javax.swing.*;
class ConfirmDialogExample {
public static void main(String[] args) {
int choice = JOptionPane.showConfirmDialog(null,
"Erase your hard disk?");
if (choice == JOptionPane.YES_OPTION) {
JOptionPane.showMessageDialog(null, "Disk erased!");
} else {
JOptionPane.showMessageDialog(null, "Cancelled."); }

10. Internal Containers Not Top level containers
Can contain other non-top level components
Examples:
JScrollPane: Provides a scrollable view of its components
JSplitPane: Separates two components
JTabbedPane: User chooses which component to see

11. Containers - Layout Each container has a layout manager
Determines the size, location of contained widgets.
Setting the current layout of a container: void setLayout(LayoutManager lm)
LayoutManager implementing classes:
BorderLayout
BoxLayout
FlowLayout
GridLayout

12. Swing Components

13. Event-driven Programming
program's execution is indeterminate
on-screen components cause events to occur when they are clicked / interacted with
events can be handled, causing the program to respond, driving the execution thru events (an "event-driven" program)

14. Action events (ActionEvent)
most common / simple event type in Swing
represent an action occurring on a GUI component
created by:
button clicks
check box checking / unchecking
menu clicks
pressing Enter in a text field
etc.

15. Listening for events attach listener to component
listener’s appropriate method will be called when event occurs (e.g. when the button is clicked)
for Action events, use ActionListener