Question

I Have one JButton variable which i used to create different buttons with different number on it

JButton numb;
numb = new JButton("7");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipadx = 30;
    c.ipady = 30;
    c.gridx = 0;
    c.gridy = 3;
    c.gridwidth = 1;
    displayPanel.add(numb, c);
    numb.setFont(new Font("arial",Font.BOLD,20));
    numb.addActionListener(this);

    numb = new JButton("8");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipadx = 30;
    c.ipady = 30;
    c.gridx = 1;
    c.gridy = 3;
    c.gridwidth = 1;
    displayPanel.add(numb, c);
    numb.setFont(new Font("arial",Font.BOLD,20));
     numb.addActionListener(this);

    numb = new JButton("9");
    c.fill = GridBagConstraints.HORIZONTAL;
    c.ipadx = 30;
    c.ipady = 30;
    c.gridx = 2;
    c.gridy = 3;
    c.gridwidth = 1;
    displayPanel.add(numb, c);
    numb.setFont(new Font("arial",Font.BOLD,20));
    numb.addActionListener(this);

Like So

when my buttons get clicked i wane read the text from the button thats got pressed

My actionPerformed looks like this

public void actionPerformed(ActionEvent e) {
    // add your event handling code here
    if (e.getSource()==numb){

        String button = (String)e.getActionCommand();

        display.setText(button); 

        System.out.println(button);

    }else if (e.getSource()==opButton){

        System.out.println(button);
    }

}

Answer 1

Well you can print the text of whatever button was clicked on like this:

JButton button = (JButton) e.getSource();
String text = button.getText();
display.setText(text);
System.out.println(text);

… but it’s not really clear what you’re trying to do. In particular, you’ve reassigned the value of numb several different times – it can’t refer to all of those buttons. You might want to give all of the buttons a common action command, e.g. “digit”. Then you can use:

private static final String DIGIT_COMMAND = "digit";

// Assign the action command of each button as DIGIT_COMMAND...

...

public void actionPerformed(ActionEvent e) {
    if (DIGIT_COMMAND.equals(e.getActionCommand()) {
        JButton button = (JButton) e.getSource();
        String text = button.getText();
        display.setText(text);
        System.out.println(text);
    } else {
        // Handle other commands
    }
}