Making all button size same

java, swing

Solution

Here is one way to achieve this using a `GridLayout`. I also introduced an additional `JPanel` so that the buttons are not stretched when the `JFrame` is resized and I chose the `GridBagLayout` for it so that it will center the button panel vertically. There are definitely other ways to solve your issue.

One thing you should try to avoid is to force preferred/maximum/minimum sizes. Delegate this to the L&F and the LayoutMananager's.

If you call `pack()` on a `JFrame`, it is useless to set its size previously, as `pack()` will change that anyway. Try to make the call to `setVisible(true);` the last line of your GUI initialization.

If you want to understand properly how layout, positioning, sizing, etc... works in Swing, I would strongly recommend to read the tutorial on LayoutManager's.

import java.awt.BorderLayout;
import java.awt.GridBagLayout;
import java.awt.GridLayout;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

public class GUI extends JFrame {
    private JButton open, process;
    private JLabel center;
    private JScrollPane scroll;
    private JPanel box;

    public GUI() {
        open = new JButton("Open Image");
        // open.addActionListener(new OpenImageAction());
        process = new JButton("Process");
        // process.addActionListener(new ProcessAction());

        box = new JPanel(new GridLayout(2, 1));
        box.add(open);
        box.add(process);
        JPanel west = new JPanel(new GridBagLayout());
        west.add(box);

        center = new JLabel("Some center label");
        scroll = new JScrollPane(center);

        getContentPane().add(west, BorderLayout.WEST);
        getContentPane().add(scroll);

        this.pack();
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (java.lang.Exception e) {
            JOptionPane.showMessageDialog(null, "GUI Error");
        }
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new GUI();
            }
        });
    }
}

Problem

Original source

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