Swings and Inner Classes

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Swings and Inner Classes

Hsuan-Tien Lin

Department of CSIE, NTU

OOP Class, June 14-15, 2010

H.-T. Lin (NTU CSIE) Swings and Inner Classes OOP 06/14-06/15/2010 0 / 12

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Getting Started with GUI

1 i m p o r t j a v a x . swing . ∗ ;

2 p u b l i c c l a s s GUIDemo {

3 p u b l i c s t a t i c v o i d main ( S t r i n g [ ] argv ) {

4 JFrame frm = new JFrame ( ) ;

5 frm . s e t V i s i b l e (t r u e) ;

6 }

7 }

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Setting Size of Frame

4 JFrame frm = new JFrame ( ) ;

5 frm . s e t S i z e ( 6 4 0 , 480) ;

6 frm . s e t V i s i b l e (t r u e) ;

7 }

8 }

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Inheriting from JFrame

4 JFrame frm = new MyFrame ( " l a l a l a " ) ;

5 }

6 }

7 c l a s s MyFrame extends JFrame {

8 MyFrame ( S t r i n g t i t l e ) {

9 super( t i t l e ) ;

10 s e t S i z e ( 6 4 0 , 480) ;

11 s e t V i s i b l e (t r u e) ;

12 }

13 }

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Adding Components to JFrame

2 J L a b e l l b l ;

5 s e t S i z e ( 6 4 0 , 480) ;

6 l b l = new J L a b e l ( " u n d e f i n e d " ) ;

7 add ( l b l ) ;

8 s e t V i s i b l e (t r u e) ;

9 }

10 }

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Using CounterLabel as both JLabel and Runnable

1 i m p o r t j a v a . awt . ∗ ;

5 s e t S i z e ( 6 4 0 , 480) ; s e t V i s i b l e (t r u e) ;

6 f o r(i n t i = 0 ; i <10; i ++) new Counter Label (t h i s) ;

7 s e t L a y o u t (new FlowLayout ( ) ) ;

8 }

9 }

10 c l a s s CounterLa bel extends J L a b e l implements Runnable {

11 i n t c oun t = 0 ;

12 Counte rLabel ( C o n t a i n e r c o n t a i n e r ) {

13 c o n t a i n e r . add (t h i s) ;

14 (new Thread (t h i s) ) . s t a r t ( ) ;

15 }

16 p u b l i c v o i d run ( ) {

17 w h i l e(t r u e) {

18 t r y{ Thread . s l e e p ( 1 0 0 0 ) ; }

19 c a t c h( I n t e r r u p t e d E x c e p t i o n e ) { }

20 co unt ++;

21 t h i s. s e t T e x t ( " " + cou nt ) ;

22 }

23 }

24 }

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Writing CounterLabel by Inner Thread Class

1 c l a s s CounterLa bel extends J L a b e l {

2 i n t c oun t = 0 ;

5 (new CounterThread ( ) ) . s t a r t ( ) ;

6 }

7 c l a s s CounterThread extends Thread {

9 w h i l e(t r u e) {

10 t r y{

11 Thread . s l e e p ( 1 0 0 0 ) ;

12 }

14 co unt ++;

15 s e t T e x t ( " " + c oun t ) ;

16 }

17 }

18 }

19 }

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Writing CounterLabel by Anonymous Thread Class

2 i n t c oun t = 0 ;

5 (new Thread ( ) {

7 w h i l e(t r u e) {

8 t r y{

9 Thread . s l e e p ( 1 0 0 0 ) ;

10 }

12 co unt ++;

13 s e t T e x t ( " " + c oun t ) ;

14 }

15 }

16 } ) . s t a r t ( ) ;

17 }

18 }

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Inner Class

easily share (private) data of outer-class instances

—usually as instance-specific, private utility class

often also do-able with interfaces, but clearer if used appropriately anonymous class: a extreme if the specific class is only needed

“temporarily”

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A CounterLabel that Stops

2 i n t c oun t = 0 ;

3 boolean s t o p p i n g = t r u e;

7 }

8 v o i d s t a r t ( ) { s t o p p i n g = f a l s e; }

9 v o i d s t o p ( ) { s t o p p i n g = t r u e; }

10 c l a s s CounterThread extends Thread {

12 w h i l e(t r u e) {

13 t r y{

14 Thread . s l e e p ( 1 0 0 0 ) ;

15 }

17 i f ( ! s t o p p i n g ) {

18 co unt ++;

19 s e t T e x t ( " " + c oun t ) ;

20 }

21 }

22 }

23 }

24 }

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A CounterLabel that Comes with a Control Button

2 C o n t r o l B u t t o n b u t = new C o n t r o l B u t t o n ( ) ;

5 c o n t a i n e r . add ( b u t ) ;

7 }

8 v o i d s t a r t ( ) { s t o p p i n g = f a l s e; b u t . r e s e t T e x t ( ) ; }

9 v o i d s t o p ( ) { s t o p p i n g = t r u e; b u t . r e s e t T e x t ( ) ; }

10 c l a s s C o n t r o l B u t t o n extends J B u t t o n {

11 C o n t r o l B u t t o n ( ) { r e s e t T e x t ( ) ; }

12 v o i d r e s e t T e x t ( ) { s e t T e x t ( s t o p p i n g ? " S t a r t " : " Stop " ) ; }

13 }

14 }

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A Control Button that Can Be Pressed

1 i m p o r t j a v a . awt . ev ent . ∗ ;

3 c l a s s C o n t r o l B u t t o n extends J B u t t o n {

4 C o n t r o l B u t t o n ( ) {

5 r e s e t T e x t ( ) ;

6 a d d A c t i o n L i s t e n e r (new A c t i o n L i s t e n e r ( ) {

7 p u b l i c v o i d a c t i o n P e r f o r m e d ( A c t i o n E v e n t e ) {

8 s t o p p i n g = ! s t o p p i n g ;

9 r e s e t T e x t ( ) ;

10 }

11 } ) ;

12 }

13 v o i d r e s e t T e x t ( ) { s e t T e x t ( s t o p p i n g ? " S t a r t " : " Stop " ) ; }

14 }

15 }

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Event Driven Programming

throw-exception-catch event: any Throwable event generator: throw event handler: catch

handler registration: write after try component-action-listener

event: ActionEvent

event generator: some component event handler: ActionListener

handler registration: addActionListener component-mouse-listener

event: MouseEvent

event generator: some component event handler: MouseListener

handler registration: addMouseListener ...

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Event Driven Programming

throw-exception-catch event: any Throwable event generator: throw event handler: catch

handler registration: write after try component-action-listener

event: ActionEvent

event generator: some component event handler: ActionListener

handler registration: addActionListener component-mouse-listener

event: MouseEvent

event generator: some component event handler: MouseListener

handler registration: addMouseListener ...

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