find JButton source in another ArrayList

Question

I am trying to build a GUI application that will let the user to choose product by clicking the button. I hold products in an ArrayList and then use this ArrayList and for loop to create proper number of JButtons. When user clicks the button price of that product should appear in the TextField. My problem is: how to find out which button was clicked? If I was using Array of Buttons (JButton button[] = new JButton[3]) I would find it in the loop: if (target.equals(button[i]))... But I can't figure out how to find it when I use ArrayList of products to create buttons. Any help would be well appreciated. Here's my code (I tried many approaches so I only post the one I started with - it finds only the last item in the ArrayList).

public void addStuff() {
stuffList.add(new Stuff("Lemon Haze", 15.00));
stuffList.add(new Stuff("OG Kush", 16.00));
stuffList.add(new Stuff("Strawberry Cough", 18.00));
for (int i = 0; i < stuffList.size(); i++) {
    stuffButton = new JButton();
    stuffPanel.add(stuffButton);
    stuffButton.setText(stuffList.get(i).getName());
    stuffButton.addActionListener(this);
}

}

public void actionPerformed(ActionEvent e) {
Object target = e.getSource();
for (int i = 0; i < stuffList.size(); i++) {
    if (target == stuffButton) {
        subtotalTextF.setText(stuffList.get(i).getPrice() + "");
    }
}

}

Krease · Accepted Answer · 2018-09-23 19:35:45Z

1

Create a specific class for your ActionListener, and give it a reference to your Stuff - this way you can create a specific instance for each button that automatically links back to the correct instance of Stuff, without trying to search on the fly:

stuffButton.addActionListener(new StuffListener(stuffList.get(i));

...

private class StuffListener implements ActionListener {
    private final Stuff myStuff;
    public StuffListener(Stuff stuff) {
        this.myStuff = stuff;
    }

    public void actionPerformed(ActionEvent e) {
        subtotalTextF.setText(String.valueOf(myStuff.getPrice()));
    }
}

Note that you can accomplish this with a bit less code using lambdas, but figured this is the clearest way to explain the logic, which is the same either way.

On a side note, based on the code you've posted, the reason it's only getting the last button is because you're comparing to stuffButton, which is not changed from the last instance after your initialization loop is done.

answered Sep 23, 2018 at 19:35

Krease

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2 Comments

MikeL Over a year ago

Jesus man - 10 min and you already have the answer for me! Thank's a lot. Really appreciate it!

Krease Over a year ago

If this solves it, don't forget to vote/accept the answer :)

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