Introduction to Java GUI Programming
Java GUI
AWT to Swing
•
AWT: Abstract Windowing Toolkit
•
import java.awt.*
•
Swing: new with Java2
•
import javax.swing.*
•
Extends AWT
•
Tons o’ new improved components
•
Standard dialog boxes, tooltips, …
•
Look-and-feel, skins
•
Event listeners
•
API:
•
http://java.sun.com/j2se/1.3/docs/api/index.html
Swing Set Demo
J2sdk/demo/jfc/SwingSet2
•
Many predefined
GUI components
GUI Component API
•
Java: GUI component = class
•
Properties
•
•
Methods
•
•
Events
•
JButton
Using a GUI Component
1.
Create it
•
Instantiate object: b = new JButton(“press me”);
2.
Configure it
•
Properties: b.text = “press me”; [avoided in java]
•
Methods: b.setText(“press me”);
3.
Add it
•
panel.add(b);
4.
Listen to it
•
Events: Listeners
JButton
Anatomy of an Application GUI
JPanel
JButton
JFrame
JLabel
GUI
Internal structure
JFrame
JPanel
JButton
JLabel
containers
Using a GUI Component 2
1.
Create it
2.
Configure it
3.
Add children (if container)
4.
Add to parent (if not JFrame)
5.
Listen to it
order
important
Build from bottom up
•
Create:
•
Frame
•
Panel
•
Components
•
Listeners
•
Add: (bottom up)
•
listeners into components
•
components into panel
•
panel into frame
JPanel
JButton
Listener
JFrame
JLabel
Code
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
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.setVisible(true);
}
}
press me
Layout Manager Heuristics
Left to right,
Top to bottom
c
n
s
e
w
FlowLayout
GridLayout
BorderLayout
none,
programmer
sets x,y,w,h
null
One at a time
CardLayout
GridBagLayout
JButton
Combinations
JButton
JButton
JTextArea
Combinations
n
JPanel: BorderLayout
c
JFrame
JPanel: FlowLayout
JButton
JButton
JTextArea
Code: null layout
JFrame f = new JFrame(“title”);
JPanel p = new JPanel( );
JButton b = new JButton(“press me”);
b.setBounds(new Rectangle(10,10, 100,50));
p.setLayout(null);
// x,y layout
p.add(b);
f.setContentPane(p);
press me
Code: FlowLayout
JFrame f = new JFrame(“title”);
JPanel p = new JPanel( );
FlowLayout L = new FlowLayout( );
JButton b1 = new JButton(“press me”);
JButton b2 = new JButton(“then me”);
p.setLayout(L);
p.add(b1);
p.add(b2);
f.setContentPane(p);
Set layout mgr before adding components
press me
then me
Applets
•
JApplet is like a JFrame
•
Already has a panel
•
Access panel with JApplet.getContentPane( )
import javax.swing.*;
class hello
extends JApplet
{public void
init
(){JButton b = new JButton(“press me”);
getContentPane().add(b);
}
}
JApplet
contentPane
JButton
Applet Methods
•
Called by browser:
•
init( )
- initialization
•
start( )
- resume processing (e.g. animations)
•
stop( )
- pause
•
destroy( )
- cleanup
•
paint( )
- redraw stuff (‘expose’ event)
Application + Applet
import javax.swing.*;
class helloApp {public static void main(String[] args){// create Frame and put my mainPanel in it
JFrame f = new JFrame(“title”);
mainPanel p = new mainPanel();
f.setContentPane(p);
f.show();
}
}
class helloApplet extends JApplet {public void init(){// put my mainPanel in the Applet
mainPanel p = new mainPanel();
getContentPane().add(p);
}
}
// my main GUI is in here:
class mainPanel extends JPanel {mainPanel(){setLayout(new FlowLayout());
JButton b = new JButton(“press me”);
add(b);
}
}
JApplet
contentPane
JPanel
JFrame
JButton
or
Browser
Command line
Applet Security
•
No read/write on client machine
•
Can’t execute programs on client machine
•
Communicate only with server
•
“Java applet window” Warning
Java GUI programming involves transitioning from AWT to Swing, utilizing prebuilt components, and understanding the anatomy of a GUI application. Learn how to create, configure, and interact with GUI components such as buttons and labels, and build applications from the bottom up. Explore sample code snippets to kickstart your GUI development journey.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. Download presentation by click this link. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
E N D
Presentation Transcript
AWT to Swing AWT: Abstract Windowing Toolkit import java.awt.* Swing: new with Java2 import javax.swing.* Extends AWT Tons o new improved components Standard dialog boxes, tooltips, Look-and-feel, skins Event listeners API: http://java.sun.com/j2se/1.3/docs/api/index.html
Swing Set Demo J2sdk/demo/jfc/SwingSet2 Many predefined GUI components
GUI Component API Java: GUI component = class Properties Methods Events JButton
Using a GUI Component 1. Create it 2. Configure it 3. Add it 4. Listen to it Instantiate object: b = new JButton( press me ); Properties: b.text = press me ; [avoided in java] Methods: b.setText( press me ); panel.add(b); JButton Events: Listeners
Anatomy of an Application GUI GUI Internal structure JFrame JFrame JPanel containers JPanel JButton JButton JLabel JLabel
Using a GUI Component 2 1. Create it 2. Configure it 3. Add children (if container) 4. Add to parent (if not JFrame) 5. Listen to it order important
Build from bottom up Create: Listener Frame Panel Components Listeners JButton JLabel Add: (bottom up) listeners into components components into panel panel into frame JPanel JFrame
Code JFrame f = new JFrame( title ); JPanel p = new JPanel( ); JButton b = new JButton( press me ); p.add(b); f.setContentPane(p); // add panel to frame // add button to panel f.show(); press me
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); f.setContentPane(p); // add panel to frame // add button to panel } } f.setVisible(true); press me
Layout Manager Heuristics FlowLayout GridLayout null none, Left to right, Top to bottom programmer sets x,y,w,h GridBagLayout BorderLayout CardLayout n w e JButton c One at a time s
Combinations JButton JButton JTextArea
Combinations JButton JButton JFrame n JPanel: FlowLayout JPanel: BorderLayout c JTextArea
Code: null layout JFrame f = new JFrame( title ); JPanel p = new JPanel( ); JButton b = new JButton( press me ); b.setBounds(new Rectangle(10,10, 100,50)); p.setLayout(null); p.add(b); f.setContentPane(p); // x,y layout press me
Code: FlowLayout JFrame f = new JFrame( title ); JPanel p = new JPanel( ); FlowLayout L = new FlowLayout( ); JButton b1 = new JButton( press me ); JButton b2 = new JButton( then me ); p.setLayout(L); p.add(b1); p.add(b2); f.setContentPane(p); press me then me Set layout mgr before adding components
Applets JApplet JApplet is like a JFrame Already has a panel Access panel with JApplet.getContentPane( ) contentPane import javax.swing.*; JButton class hello extends JApplet { public void init(){ JButton b = new JButton( press me ); getContentPane().add(b); } }
Applet Methods Called by browser: init( ) start( ) - resume processing (e.g. animations) stop( ) - pause destroy( ) - cleanup paint( ) - redraw stuff ( expose event) - initialization
Application + Applet import javax.swing.*; Command line Browser class helloApp { public static void main(String[] args){ // create Frame and put my mainPanel in it JFrame f = new JFrame( title ); mainPanel p = new mainPanel(); f.setContentPane(p); f.show(); } } JFrame JApplet or class helloApplet extends JApplet { public void init(){ // put my mainPanel in the Applet mainPanel p = new mainPanel(); getContentPane().add(p); } } contentPane // my main GUI is in here: class mainPanel extends JPanel { mainPanel(){ setLayout(new FlowLayout()); JButton b = new JButton( press me ); add(b); } } JPanel JButton
Applet Security No read/write on client machine Can t execute programs on client machine Communicate only with server Java applet window Warning
