ActionListener question

[oim415]

If you have an array of objects, TextFields or buttons in a frame, how can you reference that object's index in the actionlistener? For example, I have 7 TextFields set up as an array and need to pass it's index as a string to a method when it gets the focus.


What I have is:

public static void main(String[] args) {

//other code
ASimpleClass asc = new ASimpleClass();
JTextField[] loc = new JTextField[7];
for(int i=0; i<7;i++){

loc[i] = new JTextField(""+i,3);
loc[i].addFocusListener(this);
add(loc[i]);

}
//more code

}

public void FocusGained(FocusEvent e){

/* Alternatively I could do this but it seems brute force.
JTextField source = (JTextField)e.getComponent();
String mystring = asc.getResult(source.getText());
*/

String mystring = asc.getResult("the index of the textfield that got Focus");
//do some stuff

}

public class ASimpleClass(){

public String getResult(String str) {

String result = str;
return result;

}

}

[Fubarable]

Consider creating and posting a very small, simple compilable and runnable program that shows your problem, an SSCCE.

[oim415]

Ok, so here's a little app. Right now I have each text field hold the number of the index which I use to compare with the location of Waldo. I'd like to be able to reference the TextField's index (if that's possible). If not, is there a more elegant way that I could do this. I'd like to extend this out to a multi-dimentional array of TextFields.

import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;

public class WhereIsWaldo extends JFrame implements FocusListener {

	private JPanel contentPane;
	private JPanel gridPane;
	private JPanel messagePane;
	int waldoIsHere = (int) (Math.random()*5); //generate a random number between 0-4
	ASimpleClass dot;
	JLabel msg;
	
	public WhereIsWaldo() {
		super("Where is Waldo");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setBounds(100, 100, 450, 300);
		contentPane = new JPanel();
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
		contentPane.setLayout(new BorderLayout(0, 0));
		setContentPane(contentPane);
		gridPane = new JPanel();
		JTextField[] loc = new JTextField[5];
		for(int i=0; i<loc.length;i++){
			loc[i] = new JTextField(""+i,3);
			loc[i].addFocusListener(this);
			gridPane.add(loc[i]);
		}		
		messagePane = new JPanel();
		msg = new JLabel("Where is Waldo?.");
		messagePane.add(msg);	
		contentPane.add("North", gridPane);
		contentPane.add("South", messagePane);
		setVisible(true);	
		dot = new ASimpleClass(); 
		dot.setLocation(waldoIsHere);
	}
	
	public void focusGained(FocusEvent e){
		JTextField source = (JTextField)e.getComponent();	
		if (dot.getLocation()==Integer.parseInt(source.getText())){
			msg.setText("You've found Waldo!");
		} else{
			msg.setText("Try Again!");
		}	
	}
	
	public void focusLost(FocusEvent e){		
	}

	public static void main(String[] args) {
		WhereIsWaldo frame = new WhereIsWaldo();
		frame.setVisible(true);			
	}
}
class ASimpleClass{
	int location;
	
	public int getLocation() {
		return location;
	}
	public void setLocation(int locs){
		location = locs;
	}
}

[Fubarable]

To do what you wish, all you need to do is make loc a class field, not a variable that is local to the constructor. Then in the actionPerformed use a for loop to iterate through loc[i] to see if the source == loc[i], and if so, check if i == whereiswaldo. That's it.

[oim415]

thanks. got it to work.

[Fubarable]

Good deal, and thanks for getting back to us with your success!