java2 swing

Java Swing Chris North cs3724: HCI

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 Create it Instantiate object: b = new JButton(“press me”); Configure it Properties: b.text = “press me”; [avoided in java] Methods: b.setText(“press me”); Add it panel.add(b); 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 Create it Configure it Add children (if container) Add to parent (if not JFrame) 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.show(); } } press me

Layout Managers Automatically control placement of components in a panel Why?

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

java2 swing

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java2 swing