Managing Event, Pop-up, check box, label and Handling Event
model-view observer <- interface requires update method
Observer <- abstract class
Example
class Observer Int extends Observable {
int value;
.
.
.
setValue( );
getValue( );
i.setValue(i.getValue( ) + 1);// corresponding to C code i=i+1;
}
Managing Event
Events are apart AWT
mouse down
mouse up
mouse rotation
keyboard action
Example
public Boolean mouseDown(Event e, int x, int y){
anchor = new Point(x, y);
return true;
}
Point anchor;
Example
public Boolean mouseUp(Event e, int x, int y){
Point rmove = new Point(x - anchor.x, anchor.y - y);
String objectString = objectMoveChoice.getSelectedItem( );
if(objectString.equals("Camera")){
Repaint( );
return true;
}
if(objectString.equals("Camera")){
Camera c = (Camera)Camera;
c.auto_Pan = ap_cb.getState( );
C.change_config( rmove );
compute_ranges( );
Repaint( );
return true;
}
Pop-Up Option
Example
public class SimpleDraw extends Applet{
Choice objectMoveChoice;
}
public void add_move_choice_menu( ){
objectMoveChoice = new choice( );
objectMoveChoice.addItem("Object Properties");
add(objectMoveChoice);
}
Example(submethod)
public void create_gui( ){
setBackground(color.white);
add_check_boxes( );
add_label_scrollbars( );
add_move_comemenu( );
Adding Check Box
Example
checkbox ap_cb = new checkbox("auto_Pan", null, true);
//if ap_cb getState( )
checkbox checkboxes[ ]{ ap_cb, … ,};
//store into array
public void add_checkBoxes( ){;//add check box
for(int i=0; i<checkboxes.length; i++){
add(checkBoxes[i]);
}
Adding Label
Example
public void add_labels_add_scrollbars( ){
add(new Label("Rho"));
rho_l = new Label("45");
rho_scrollbars = new ScrollBar(ScrollBar.VERTICAL,
set.length.VERTICAL(VX));
add(rho_l);
add(rho_scrollbars);
}
Handling Event
Example
public Boolean handling_ScrollBar(Event 'e'){
double f= f_scrollbars.getValue( )/100;
f_l.setText(String ValueOf(f));
c.F = f;
return true;
}
Example
public Boolean handling Event(Event 'e'){
if (e.target instanceOfScrollBar){
return_handel_ScrollBar(e);
}
return Super.handelEvent(e);
}
Homework use code that you wrote last time to add check box to select prof's face, to add pop up menu to select background some colors, to add scroll bar to translate prof's move with your motion.
Last Update: 11/28/96