Adding Swing Elements to JFrame with BorderLayout and existing JScrollPane

Question

package Input;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ScrollPaneConstants;

public class ProgramEditor2 {
    JFrame frame;
    JPanel contactListPanel;
    ArrayList<JButton> program;

    public ProgramEditor2() {
        initialize();
    }

    ActionListener al = new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            LineEditor.main((JButton) arg0.getSource(),program,contactListPanel);
        }
    };

    public void initialize() {
        frame = new JFrame();
        frame.setSize(471, 298);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);
        frame.setVisible(true);
        frame.getContentPane().setLayout(new BorderLayout());

        program = new ArrayList<JButton>();

        // Set layout for contactListPane
        contactListPanel = new JPanel();
        contactListPanel.setLayout(new GridLayout(15, 1)); // 15 rows, 1 column
        contactListPanel.setMinimumSize(new Dimension(471, 298));
        contactListPanel.setPreferredSize(new Dimension(471, 298));
        contactListPanel.setMaximumSize(new Dimension(471, 298));
        for (int i = 0; i < 1; i++) {
            JButton button = new JButton();
            button.addActionListener(al);
            contactListPanel.add(button);
        }
        JScrollPane scrollPane = new JScrollPane(contactListPanel);
        scrollPane
                .setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
        frame.getContentPane().add(scrollPane, BorderLayout.CENTER);

    }

    public static void main(String[] args) {
        new ProgramEditor2();
    }
}

I am trying to add a JLabel above the scrollpanel, and two JButtons below it.I believe the issue is the fact that I am setting the frame layout to BorderLayout at line 57. How can I got about fixing this problem?

`frame.add(new JLabel("Hello"), BorderLayout.NORTH)`;? – MadProgrammer Apr 30 '15 at 01:03 — MadProgrammer, Apr 30 '15 at 01:03

score 3 · Accepted Answer · edited May 23 '17 at 10:24

Start by having a closer look at How to Use BorderLayout

I am trying to add a JLabel above the scrollpanel

frame.add(new JLabel("Hello"), BorderLayout.NORTH);

and two JButtons below it

Use a "compound layout" approach by using a different container with a different layout manager, which meets the requirements for the inner components, then add this container to the parent container, for example

JButton btn1 = ...;
JButton btn2 = ...;
JPanel buttons = new JPanel();
buttons.add(btn1);
buttons.add(btn2);

frame.add(buttons, BorderLayout.SOUTH);

Side notes:

Instead of frame.setSize(471, 298);, I'd recommend using JFrame#pack, but I'd only do this AFTER you've established the base UI.
frame.getContentPane().setLayout(null); is a bit pointless
frame.setVisible(true); should be called last, after you have established the UI, otherwise some components may not appear
Avoid using etMinimumSize, setPreferredSize, setMaximumSize, they can adversely affect the layouts if you're not careful. See Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing? for more discussions. If you want to change the way a JScrollPane works, then use the Scrollable interface instead

Compound layouts are pretty common, so spending time getting to use it is worthwhile — MadProgrammer, May 01 '15 at 22:45

Adding Swing Elements to JFrame with BorderLayout and existing JScrollPane

1 Answers1

Side notes: