JTextField[ ] - index of event source?

[Katrina Owen]

Hi,

I think I am missing something obvious, or forgetting something very fundamental.

I am creating a user interface which requires an (n x n) grid of input areas (initial values can be read from file or entered manually by the user), and I have chosen to make an array of JTextField arrays

JTextField[][] fields;

I then populate the fields (or not) based on initial values, and if my program generates new values / additional values, I am able to update the display.

public void displaySolution( int[][] solution )
{
    for ( int i = 0; i < init.getSize(); i++ )
    {
        for ( int j = 0; j < init.getSize(); j++ )
        {
            JTextField t = fields[ i ][ j ];
            t.setText( solution[ i ][ j ] + "" );
        }
    }
}

If a user inputs something to a field, this information is visible on screen, however I have no idea where to start in order identify *which* field so that I can update my data structure.

I can think of the following options:
Create an ActionListener which can be added to all the fields, and somehow

i) use getSource() to (somehow) figure out which field I am dealing with
or
ii) iterate through the whole thing reading the text, comparing to previous state, and dealing with text if it has changed
or
iii) any suggestions?

Should I try to isolate more of my code to show what/how I am thinking?

Katrina
[ April 11, 2007: Message edited by: Katrina Owen ]

[Ilja Preuss]

I would simply instanciate a separate listener for each field.

[Katrina Owen]

The problem I have with separate listeners, is that I can have anything from 16 to 100-plus fields, and this number will vary every time the program is run.

[Paul Clapham]

So you will have 16 to 100 listeners. Why is that a problem?

[Justin Fox]

instead of using JUST JTextFields, why not incorporate an object that
not only has a JTextField as private member data, but a specific private
string that the object can use to uniquely identify that certain JTextField with?

Justin
[ April 11, 2007: Message edited by: Justin Fox ]

[Justin Fox]

but then again, i dont understand what you are doing? is the user updating
the database then you go in and save it in the actual array of JTextfields?

if thats the case, you don't need to know the actual name/spot in the array of the modified textfield, just make a back up string or just go through and JTextField.setText() to each one every time the use presses
"update" or "re-set"

is this what you are wanting to be able to do?

Justin

[Katrina Owen]

My trouble with making 16 to 100 listeners is that I don't know how to make a variable amount of listeners as I need them, rather than hard coding them. Hard coding 144 listeners seemed like overkill (and pretty daunting).

Now that I have thought about it, there are probably appropriate factory methods for such things, but I am still a bit green for such things.

While working on my code I realized what essential little bit of obviousness had escaped me:

JTextField t = e.getSource();

(D'oh!)

I also decided to add an inner Location class to my view

class Location
{
    private int row;
    private int col;
 
    Location( int i, int j )
    {
        row = i;
        col = j;
    }
}

This allows me to use my JTextFields as keys in a HashMap, the value being the Location. Consequently, I can use the position of the text field to update the information at the relevant location elsewhere in the program, or to obtain information for the relevant location.

JTextfield t = e.getSource();
Location loc = myMap.get( t );
int i = loc.row;
int j = loc.col;
int value = control.get( i, j );

The project is a GUI for a game - no database involved

Thanks for the feedback and help on this!

Katrina
[ April 11, 2007: Message edited by: Katrina Owen ]