Event Handling Model of AWT Event object Event

Event Handling Model of AWT Event object Event handling methods Event source Event listener

Action Events on Buttons Action. Event action. Performed(. . ) Button Action. Listener

How to Attach an Event Listener to an Event Source o is an event source h is an event listener of type XXX o. add. XXX(h) where XXX is one of the following: Component. Listener Action. Listener Focus. Listener Mouse. Motion. Listener Text. Listener Key. Listener Adjustment. Listener Window. Listener Item. Listener

The Action. Listener Interface interface Action. Listener { public void action. Performed(Action. Event e); } 4 Possible event sources – Button – List – Text. Field – Menu. Item

Example Hello World (version 1) import java. awt. *; import java. awt. event. *; public class Test. Button. Action { public static void main(String[] args){ Frame f = new Frame("Test. Button"); f. set. Size(200, 200); Button hw = new Button("Hello World!"); f. add(hw); hw. add. Action. Listener(new Action. Listener(){ public void action. Performed(Action. Event e){ System. exit(0); } }); f. set. Visible(true); } }

Example Hello World (version 2) class My. Frame extends Frame implements Action. Listener { Button hw; public My. Frame(){ super("Test Button"); set. Size(200, 200); hw = new Button("Hello World!"); add(hw); hw. add. Action. Listener(this); show(); } public void action. Performed(Action. Event o){ System. exit(0); } }

Example Hello World (version 3) class My. Frame extends Frame { Button hw; public My. Frame(){ super("Test Button"); set. Size(200, 200); hw = new Button("Hello World!"); add(hw); hw. add. Action. Listener(new My. Action. Listener()); show(); class My. Action. Listener implements Action. Listener { public void action. Performed(Action. Event o){ System. exit(0); } }

Revisit Card. Layout Flip Cards Menu. Item bp = new Menu. Item("Flip to Button Panel"); bp. add. Action. Listener(new Action. Listener(){ public void action. Performed(Action. Event e){ Card. Layout layout = (Card. Layout)f. get. Layout(); layout. show(f, "Button. Panel"); } });

How to Use File. Dialog? Menu m 1 = new Menu("File"); Menu. Item open = new Menu. Item("Open"); m 1. add(open); mb. add(m 1); final Text. Area ta = new Text. Area(10, 10); f. add(ta); open. add. Action. Listener(new Action. Listener(){ public void action. Performed(Action. Event e){ File. Dialog dialog = new File. Dialog(f, "Open File", File. Dialog. LOAD) dialog. show(); ta. append(dialog. get. File()+"n"); } });

Mouse. Listener mouse. Clicked(Mouse. Event) Invoked when the mouse has been clicked on a component. mouse. Entered(Mouse. Event) Invoked when the mouse enters a component. mouse. Exited(Mouse. Event) Invoked when the mouse exits a component. mouse. Pressed(Mouse. Event) Invoked when a mouse button has been pressed on a componen mouse. Released(Mouse. Event) Invoked when a mouse button has been released on a compone

Mouse. Adapter class Mouse. Adapter implements Mouse. Listener { public void mouse. Clicked(Mouse. Event e){} public void mouse. Entered(Mouse. Event e){} public void mouse. Exited(Mouse. Event e){} public void mouse. Pressed(Mouse. Event e){} } public void mouse. Released(Mouse. Event e){}

Example import java. applet. *; import java. awt. event. *; public class Test. Mouse. Listener { public static void main(String[] args){ Frame f = new Frame("Test. Mouse. Listener"); f. set. Size(500, 500); f. add. Mouse. Listener(new Mouse. Adapter(){ public void mouse. Clicked(Mouse. Event e){ System. out. println("Mouse clicked: ("+e. get. X()+", "+e. get. Y } . . }

Mouse. Motion. Listener 4 mouse. Dragged(Mouse. Event) – Invoked when a mouse button is pressed on a component and then dragged.