Question

I am trying to place two JButtons next to each other in the center of a JFrame, that won’t re-size the buttons when the JFrame is re-sized.

To do this I placed the two buttons in a panel with a FlowLayout, that is then placed in a panel with a center BorderLayout.

However the following code won’t display the chosen panel in the center of the BorderLayout.

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class test extends JFrame {

    private JPanel panel1 = new JPanel();
    private JPanel panel2 = new JPanel();
    private JButton button1 = new JButton("one");
    private JButton button2 = new JButton("two");

    public test() {
        panel1.setLayout(new FlowLayout());
        panel1.add(button1);
        panel1.add(button2);

        panel2.setLayout(new BorderLayout());
        panel2.add(panel1, BorderLayout.CENTER);

        this.add(panel2);
    }

    public static void main(String[] args) {
        test frame = new test();
        frame.setVisible(true);
        frame.setSize(400, 400);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}

Answer 1

Set GridBagLayout to panel1.

 panel1.setLayout(new GridBagLayout());

EDIT:

@trashgod : I have to figure out how the default constraints do it.

Because of the field GridBagLayout.defaultConstraints :

This field holds a gridbag constraints instance containing the default
values, so if a component does not have gridbag constraints associated
with it, then the component will be assigned a copy of the
defaultConstraints.

In normal practice, one must have to create GridBagConstraints object and set fields to specify the constraints on each object.

To quote the tutorial:

The preferred approach to set constraints on a
component is to use the Container.add variant, passing it a
GridBagConstraints object