How to capture the amount of clicks over a group of loop generated JToggleButtons?

Question

I have 20 loop-generated JToggleButtons and I need to count how many of them are active.

private void generarBotones(){    
    JToggleButton b;
    this.panelCuerpo.setLayout(new GridLayout(4,5));        
    for(int i = 1; i<=20; i++){
        b = new JToggleButton();
        b.setText(String.valueOf(i));
        this.panelCuerpo.add(b);
        b.addActionListener(new ActionListener() {
            int clicks = 0;
            @Override
            public void actionPerformed(ActionEvent ae2){
                clicks = clicks + 1;
                System.out.println(clicks);
            }                
            public void setCantidadBoletas(int clicks){
                cantidadBoletas = clicks;
            }
        });
    }   
}

The problem here is that it counts how many times is EACH ONE of them clicked instead of count how many of them are selected.

PS. I tried to use (b.isSelected()) but b needs to be final to access it so it wasn't the solution.

If you declare your JToggleButton inside the loop, then it can be final. But even better, just use an ArrayList of JToggleButtons as a field and iterate through that. — Hovercraft Full Of Eels, May 30 '15 at 15:51

score 2 · Accepted Answer · answered May 30 '15 at 16:04

If you declare the JToggleButton inside the loop, you can make it final:

for (int i = 1; i<=20; i++) {
    JToggleButton b = new JToggleButton();

Then you can use b.isSelected:

    b.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent evt) {
            if (b.isSelected())
                clicks++;
            else
                clicks--;
        }
    });
}

clicks would have to be a class variable.

The most simple answer. – Andrés Buitrago Jun 03 '15 at 02:07 — Andrés Buitrago, Jun 03 '15 at 02:07

Stéphane Bruckert · Answer 2 · 2015-05-30T16:01:12.980

Create a class attribute that will count the selected toggles:

private int selectedCount;

Initialize the counter to 0 in your constructor:

this.selectedCount = 0;

Increment or decrement the counter every time the state of a toggle changes:

b.addItemListener(new ItemListener() {
    public void itemStateChanged(ItemEvent ev) {
        if (ev.getStateChange() == ItemEvent.SELECTED){
             YourClass.this.selectedCount++;
        } else if (ev.getStateChange() == ItemEvent.DESELECTED){
             YourClass.this.selectedCount--;
        }
        System.out.println(YourClass.this.selectedCount);
    }
});

score 1 · Answer 3 · answered May 30 '15 at 15:54

Suggestions:

Create a field, JToggleButton[] toggleButtons = new JToggleButton[20]
Or use an ArrayList if you so choose
In your for loop create your JToggleButton and assign it to the proper array item.
In the ActionListener simply iterate through the array, counting how many of its JToggleButton items are selected.
You're done.

score 1 · Answer 4 · answered May 30 '15 at 16:01

There are many ways to get this done and the best way depends on the rest of your code. I tried to keep it as close to yours.

You can just declare the buttons as final inside the loop and keep a global count of the number of buttons selected, which will be modified in the ActionListener:

public class ButtonsCount extends JFrame {

    int clicks = 0;

    ButtonsCount() {

        JLabel label = new JLabel("0");
        JPanel buttonsPanel = new JPanel(new GridLayout(4,5));

        for(int i = 1; i <= 20; i++) {
            final JToggleButton b = new JToggleButton();
            b.setText(String.valueOf(i));
            buttonsPanel.add(b);
            b.addActionListener(new ActionListener() {

                @Override
                public void actionPerformed(ActionEvent ae2){
                    if (b.isSelected())
                        label.setText(String.valueOf(++clicks));
                    else
                        label.setText(String.valueOf(--clicks));
                }
            });
        }

        add(buttonsPanel);
        add(label, BorderLayout.PAGE_END);

        setDefaultCloseOperation(EXIT_ON_CLOSE);
        pack();
        setLocationRelativeTo(null);
        setVisible(true);
    }

    public static void main(String[] args) {

        new ButtonsCount();
    }
}

How to capture the amount of clicks over a group of loop generated JToggleButtons?

4 Answers4