Question

I have a following JFrame.

public class AddActivityWindow extends JFrame {

    //declaration of components go here
     ...
    public AddActivityWindow(ActivityStore store) {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel pnl_date = new JPanel();
        JLabel lbl_date = new JLabel("X");
        pnl_date.add(lbl_date);
        add(pnl_date);


        pnl_activities = new JPanel();
        JLabel lbl_act = new JLabel("Y");
        pnl_activities.add(lbl_act);
        add(pnl_activities);

        setLocationRelativeTo(null);
        setVisible(true);

    }
}

When I create this Frame I was expecting that it would create a frame with two panels. But, I only see the second panel (i.e.) I only see Y on the screen and not X. However, if I remove the code for the second panel, then I can see X.

What happens when I add the second panel. Why does the first panel not show up in the frame?

Answer 1

You should be using a different Layout Manager, Have a look at : A Visual Guide to Layout Managers to select one for you.

This works fine for me ,

import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class FrameTest extends JFrame {

    public FrameTest() {
        setLayout(new FlowLayout());
        setSize(150, 150);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel pnl_date = new JPanel();
        JLabel lbl_date = new JLabel("X");
        pnl_date.add(lbl_date);
        add(pnl_date);


        JPanel pnl_activities = new JPanel();
        JLabel lbl_act = new JLabel("Y");
        pnl_activities.add(lbl_act);
        add(pnl_activities);

        setLocationRelativeTo(null);
        setVisible(true);

    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new FrameTest().setVisible(true);

            }
        });
    }
}