Java mechanism for events on a game board?

[jim.hunt533]

New to Java, I'm looking for a general way to set up a game board as a
grid of cells and communicate with them. So far I have defined a new
class, Cell, which extends JTextField and has some extra fields like
rowNo and columnNo, then populated a JPanel with a GridLayout(3,3)
with nine instances of Cell(i,j).

The problem then is how to code an event handler (like
KeyTyped(KeyEvent e)) in the Class to know which instance of Cell has
received the event.

The closest I have got so far finding ActionCommand and defining that
to be a row+column id string for the instance as it is constructed.
This is then visible in a System.out.println of the Event but I have
not found a way to extract it. I'm sure that is an abuse of
ActionCommand anyway.

Any and all ideas on better/correct techniques will be most welcome.

 

[Joshua Cranmer]

New to Java, I'm looking for a general way to set up a game board as a
grid of cells and communicate with them. So far I have defined a new
class, Cell, which extends JTextField and has some extra fields like
rowNo and columnNo, then populated a JPanel with a GridLayout(3,3)
with nine instances of Cell(i,j).

The problem then is how to code an event handler (like
KeyTyped(KeyEvent e)) in the Class to know which instance of Cell has
received the event.

The closest I have got so far finding ActionCommand and defining that
to be a row+column id string for the instance as it is constructed.
This is then visible in a System.out.println of the Event but I have
not found a way to extract it. I'm sure that is an abuse of
ActionCommand anyway.

Any and all ideas on better/correct techniques will be most welcome.

Try adding a KeyListener to every Cell object, which should know its
position.

 

[Knute Johnson]

New to Java, I'm looking for a general way to set up a game board as a
grid of cells and communicate with them. So far I have defined a new
class, Cell, which extends JTextField and has some extra fields like
rowNo and columnNo, then populated a JPanel with a GridLayout(3,3)
with nine instances of Cell(i,j).

The problem then is how to code an event handler (like
KeyTyped(KeyEvent e)) in the Class to know which instance of Cell has
received the event.

The closest I have got so far finding ActionCommand and defining that
to be a row+column id string for the instance as it is constructed.
This is then visible in a System.out.println of the Event but I have
not found a way to extract it. I'm sure that is an abuse of
ActionCommand anyway.

Any and all ideas on better/correct techniques will be most welcome.

In your KeyListener, get the source of the event, your Cell component
and take the row and column from that.

public void keyPressed(KeyEvent ke) {
Cell cell = (Cell)ke.getSource();
// then you have cell.row or cell.getRow() whatever

 

[Roedy Green]

The problem then is how to code an event handler (like
KeyTyped(KeyEvent e)) in the Class to know which instance of Cell has
received the event.

You can use a Canvas, then analyse the x,y (just divide by a constant)
to get the cell number. This will be considerably faster than having
a layout of components.

See http://mindprod.com/jgloss/event11.html

 

[jim.hunt533]

In your KeyListener, get the source of the event, your Cell component
and take the row and column from that.

public void keyPressed(KeyEvent ke) {
Cell cell = (Cell)ke.getSource();
// then you have cell.row or cell.getRow() whatever

--

Knute Johnson
email s/nospam/knute/- Hide quoted text -

- Show quoted text -

That works! That's great - many thanks - Jim

 

[jim.hunt533]

You can use a Canvas, then analyse the x,y (just divide by a constant)
to get the cell number. This will be considerably faster than having
a layout of components.

Seehttp://mindprod.com/jgloss/event11.html

Thanks Roedy - I'll keep an eye on performance and maybe go to this
technique if necessary - Jim