Question

I have an annoying problem, and I don’t seem to understand where in comes from. I have an application and a simple UI for it. The problem is that when I run the program buttons respond only to the second click. After they do what they have to do, buttons respond to the first click. I really don’t know what is the source of the problem. Here is some source code for binding jButton and actionlistener:

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:
    jButton1.addActionListener(new SolutionListener());
}

And here is actionlistener itself (if it helps):

private class ListListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        jTextArea1.setText(null);
        if (jTextField2.getText().equals("")) {
            jTextArea1.append("Input a value");
        }
        else {
            for (int i = 2; i <= Integer.valueOf(jTextField2.getText().trim()); i++) {
                if(isSquare(i) == true) {
                    continue;
                }
                else {
                    PE pe = new PE(i);
                    answer = pe.solve();
                    jTextArea1.append(i + "\t");
                    jTextArea1.append(answer[0].toString() + " ");
                    jTextArea1.append(answer[1].toString() + "\n");
                }
            }
        }
    }
}

I would really appreciate any help, thanks in advance!

Answer 1

If you try this:

    jButton1.addActionListener(new ActionListener () {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            System.out.println("outside Action");
            jButton1.addActionListener(new ActionListener () {
                public void actionPerformed(java.awt.event.ActionEvent evt2) {
                    System.out.println("inside Action");
                }
            });
        }
   });

One key click will print “outside Action” and the second will print “inside Action”.

You only need one ActionListener per JButton.