Java GUI programming with Swing Tim Mc Kenna

Java GUI programming with Swing Tim Mc. Kenna Seneca@York

Java 2 Swing Components l l l Java Foundation Classes(JFC) - Java 2 Swing components - Java 2 D graphics classes the class JComponent(API) http: //java. sun. com/products/jfc Swing Tutorial Swing Connection

Swing Components l l l button: JButton label: JLabel item selection: JCheck. Box, JRadio. Button, JToggle. Button object selection: JCombo. Box, JList, JSpinner text: JText. Field, JText. Area, JEditor. Pane, JFormatted. Text. Field, JPassword. Field menus: JMenu. Bar, JMenu. Item, . . .

Swing Components and Events Event Source JButton Event Type Generated Action. Event JText. Field Action. Event (but don't listen for it) JMenu. Item Action. Event JCombo. Box Item. Event, Action. Event JCheck. Box Item. Event JRadio. Button Item. Event (but don't listen for it) JList. Selection. Event

Swing Components l Example(Online Reservation): • Reservation. java – listens to everything • Reservation. TM. java – listens when it matters l l l a key point is WHEN components should be listened to. components often do not need a listener components can be inspected for their state: • • JText. Field. get. Text() JRadio. Button. is. Selected() JCheck. Box. is. Selected() JCombo. Box. get. Selected. Index()

Swing Components l Event Handling JRadio. Button, JCheck. Box: add. Item. Listener( ) Item. Listener interface: item. State. Changed( ) Item. Event: get. State. Change( )

Swing Components l Event Handling JCombo. Box: add. Action. Listener( ), get. Selected. Item( ), get. Selected. Index( ) JText. Field: add. Action. Listener( ) Action. Event: get. Action. Command( )

Swing Components l l l Swing Component: JList Example: JList. Demo. java Inspect JList: • get. Selected. Index() - returns -1 if there is no selection. • get. Selected. Indices() - empty array if nothing is selected • get. Selected. Value() – returns null or object referred to in the list • is. Selection. Empty() l Event Handling: add. List. Selection. Listener() • javax. swing. event. List. Selection. Listener interface • value. Changed()

Swing Components l l Example: JText. Demo. java Swing Components: JText. Field, JText. Area, JButton Event Handling: JText. Field: add. Action. Listener( ) vs. get. Text( ) l JText. Area: NO listener is registered! append( ), insert( ), set. Text( ), get. Selected. Text( ), get. Text( )