Access an Object from another file [Swing GUI]

[Steffen Lima]

Hi all,

got a very simple question which I currently have no idea how to solve (thats why I'm posting it now

I build an action listener for a button, but I used a separate file for this (class MiniGuiActionListener). So far so good. But now, when the button was clicked, I want to access the jButton object from within the actionPerformed method. How can I accomplish this? (I just want to invoke something like jButton.setText(...) ).

Thanks in advance,
Steffen

I got these two simple Java files (with all imports etc.):

public class MiniGui1 {
    JButton jButton;

    public static void main(String[] args) {
        MiniGui1 gui = new MiniGui1();
        gui.go();
    }
    
    public void go() {
        JFrame theFrame = new JFrame();
        jButton = new JButton();
        MiniGuiActionListener listen = new MiniGuiActionListener();
        
        jButton.addActionListener(listen);
        jButton.setText("Click me!");
        
        theFrame.getContentPane().add(jButton);
        theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        theFrame.setSize(300,300);
        theFrame.setVisible(true);
        } 
}

Second file:

public class MiniGuiActionListener implements ActionListener{

    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO: change button text     
    } 
}

[Campbell Ritchie]

Welcome to the Ranch
I shall move this discussion to our GUIs forum.
If the button is a local variable in that method, it ceases to exist outside the method, unless you pass a reference to it elsewhere. Why not pass a reference to the constructor of the listener class, and keep it as a field of the listener class? Then you can access it inside the listener class.

[Campbell Ritchie]

I see it is a field. You ought to have given it private access. You can pass it as an argument to eht Listener class’s constructor just the same as for a local variable.

[Steffen Lima]

Perfect - passing an object reference to the constructor just solved my little "problem"

Thank you very much !!

[Campbell Ritchie]

You’re welcome