ActionPerformed不起作用

Question

Have a little problem with this code. The actionPerformed method doesn't work. Buttons knappStartSalg and knappStartKunde , don't react when I push the buttons.

All that should have been imported are imported.

Will be very thankful for any help.

Startmeny class.

public class Startmeny extends JFrame implements ActionListener
{

    public JButton knappStartSalg, knappStartKunde, knappStartInfo, knappStartStatistikk;

    public JPanel startmeny()
    {
    JPanel startpanel = new JPanel();
    startpanel.setLayout(new GridLayout(2, 0, 25, 25) );
    startpanel.setComponentOrientation(ComponentOrientation.LEFT_TO_RIGHT);
    startpanel.setBackground(Color.white);

    JButton knappStartSalg = new JButton();
    knappStartSalg.setText("Salg");
    knappStartSalg.setVerticalTextPosition(JButton.BOTTOM);
    knappStartSalg.setHorizontalTextPosition(JButton.CENTER);
    knappStartSalg.setIcon(new javax.swing.ImageIcon(getClass().getResource("salg.png")));
    knappStartSalg.setIconTextGap(6);
    knappStartSalg.setForeground(Color.black);
    knappStartSalg.setBackground(Color.white);
    knappStartSalg.setBorderPainted(false);
    knappStartSalg.addActionListener(this);

    startpanel.add(knappStartSalg);

    JButton knappStartKunde = new JButton();
    knappStartKunde.setText("Kontroll");
    knappStartKunde.setVerticalTextPosition(JButton.BOTTOM);
    knappStartKunde.setHorizontalTextPosition(JButton.CENTER);
    knappStartKunde.setIcon(new javax.swing.ImageIcon(getClass().getResource("heiskontroll.png")));
    knappStartKunde.setIconTextGap(6);
    knappStartKunde.setForeground(Color.black);
    knappStartKunde.setBackground(Color.white);
    knappStartKunde.setBorderPainted(false);
    knappStartKunde.addActionListener(this);

    startpanel.add(knappStartKunde);

    JButton knappStartInfo = new JButton();
    knappStartInfo.setText("Informasjonsvindu");
    knappStartInfo.setVerticalTextPosition(JButton.BOTTOM);
    knappStartInfo.setHorizontalTextPosition(JButton.CENTER);
    knappStartInfo.setIcon(new javax.swing.ImageIcon(getClass().getResource("info.png")));
    knappStartInfo.setIconTextGap(6);
    knappStartInfo.setForeground(Color.black);
    knappStartInfo.setBackground(Color.white);
    knappStartInfo.setBorderPainted(false);
    knappStartInfo.addActionListener(this);

    startpanel.add(knappStartInfo);

    JButton knappStartStatistikk = new JButton();
    knappStartStatistikk.setText("Statistikk");
    knappStartStatistikk.setVerticalTextPosition(JButton.BOTTOM);
    knappStartStatistikk.setHorizontalTextPosition(JButton.CENTER);
    knappStartStatistikk.setIcon(new javax.swing.ImageIcon(getClass().getResource("statistikk.png")));
    knappStartStatistikk.setIconTextGap(6);
    knappStartStatistikk.setForeground(Color.black);
    knappStartStatistikk.setBackground(Color.white);
    knappStartStatistikk.setBorderPainted(false);
    knappStartStatistikk.addActionListener(this);

    startpanel.add(knappStartStatistikk );

    return startpanel;
}


@Override
public void actionPerformed(ActionEvent e)
{
    Salgsvindu s = new Salgsvindu();

    if(e.getSource() == knappStartSalg)
    {
        s.visSalgvinduNyBruker();
        System.out.println("hallotest");
    }
    else if(e.getSource() == knappStartKunde)
        s.visKontrollvindu();
}
}

Main-class, which runs the GUI.

public class Skisenter
{
public static void main(String[] args) 
{   
    /*Salgsvindu s = new Salgsvindu();
    s.visSalgvinduNyBruker();*/
    Startmeny startmenyinstanse = new Startmeny();

    startmenyinstanse.setSize(600, 630);
    startmenyinstanse.setTitle("Startmeny for skisenter");
    Startmeny st = new Startmeny();
    startmenyinstanse.setContentPane(st.startmeny());
    startmenyinstanse.setVisible(true);
    startmenyinstanse.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

Answer 1

In your class, you define instance variables:

public JButton knappStartSalg, knappStartKunde, knappStartInfo, knappStartStatistikk;

You use these variables in your action listener implementation. However in your constructor, you construct JButton s and assign them to new local variables, not the instance variables you declare above the constructor. So instead of:

JButton knappStartSalg = new JButton();

write

knappStartSalg = new JButton();

to assign the buttons to the instance variables and your action listener should work.