Thread: How to fill available space with FlowLayout

I am trying to make a gui, with a frame, 2 panels which are half of the height of the frame, and in the bottom panel 7 buttons next to each other using FlowLayout.
this works, but it does not fill up the available space, so if I say the preferred size of the buttons is screenWidth / 7 to make room for all 7, it places 6 buttons on one row, puts blank space on both sides, and places the last button which could fit without the blank space a row below.

Posted full code so you can copy paste and run for yourself,
but the main question is how to fill up the remaining space with that 7th button using FlowLayout.

In any case, Thank you for your time!

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.awt.Container;
public class newGui
{
    public newGui()
    {
        initUI();
 
    }
    public void addComponents(Container container)
    {
 
        JPanel display = new JPanel(); 
        JPanel interact = new JPanel();
        //sets Layout for containers
        container.setLayout(new BorderLayout());
        display.setLayout(new FlowLayout());
        interact.setLayout(new FlowLayout());
 
        display.setBackground(Color.BLACK);
 
        //creates icons for buttons
        //to run change with own jpg's
        ImageIcon[] icons = new ImageIcon[7];
        icons[0] = new ImageIcon(("hearts1.jpg"));
        icons[1] = new ImageIcon(("hearts2.jpg"));
        icons[2] = new ImageIcon(("hearts3.jpg"));
        icons[3] = new ImageIcon(("hearts4.jpg"));
        icons[4] = new ImageIcon(("hearts5.jpg"));
        icons[5] = new ImageIcon(("hearts6.jpg"));
        icons[6] = new ImageIcon(("hearts7.jpg"));
 
        //makes buttons
        JButton button1 = new JButton("derp");
        JButton button2 = new JButton("derp");
        JButton button3 = new JButton("derp");
        JButton button4 = new JButton("derp");
        JButton button5 = new JButton("derp");
        JButton button6 = new JButton("derp");
        JButton button7 = new JButton("derp");
 
        //sets icons to buttons
        button1.setIcon(icons[0]);
        button2.setIcon(icons[1]);
        button3.setIcon(icons[2]);
        button4.setIcon(icons[3]);
        button5.setIcon(icons[4]);
        button6.setIcon(icons[5]);
        button7.setIcon(icons[6]);
 
        //gets screen size and sets up dimension to use for button
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        int screenHeight = screenSize.height;
        int screenWidth = screenSize.width;
        display.setPreferredSize(new Dimension(screenWidth, screenHeight/2));  
        Dimension buttonDimension = new Dimension(screenWidth / 7, screenHeight / 2 -40 );
 
        button1.setPreferredSize(buttonDimension);
        button2.setPreferredSize(buttonDimension);
        button3.setPreferredSize(buttonDimension);
        button4.setPreferredSize(buttonDimension);
        button5.setPreferredSize(buttonDimension);
        button6.setPreferredSize(buttonDimension);
        button7.setPreferredSize(buttonDimension);
 
        //adds buttons to bottom panel
        FlowLayout flow = new FlowLayout(FlowLayout.LEFT);
 
        interact.add(button1,flow);
        interact.add(button2,flow);
        interact.add(button3,flow);
        interact.add(button4,flow);
        interact.add(button5,flow);
        interact.add(button6,flow);
        interact.add(button7,flow);
 
        //adds panels to container
        container.add(display,BorderLayout.NORTH);
        container.add(interact,BorderLayout.SOUTH);
 
    }
    //sets up frame and adds the components
    private void initUI()
    {
 
        JFrame frame = new JFrame("My App");
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
 
        frame.setSize(screenSize);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        
 
        addComponents(frame.getContentPane());
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
 
    }
 
    public static void main(String[] args)
    {
 
        javax.swing.SwingUtilities.invokeLater(new Runnable(){
 
            public void run()
            {
 
                newGui gui = new newGui();
            }
        });
 
    }
}

Have you tried using BoxLayout instead?

I can try that, I just figured there must be a way of doing this with flowlayout too

FlowLayout respects each component's preferredSize. BoxLayout will stretch or shrink components so they all fill the parent container. Switching to BoxLayout is the first thing I would try if I were you.

You could also consider GridLayout, if you want all of your components to be the same size.

Thank you all for the response, I'm using miglayout and it all seems to work
But I do have one more question, when using swing, why should I repaint(or overwrite paintComponent)?
So far I'm just swapping the corresponding icon on the JButtons and that seems to work without a hitch for now.

When I read this it seems the components used repaint themselves when necessary, so why repaint?

Thank you!

"
Swing components generally repaint themselves whenever necessary. When you invoke the setText method on a component, for example, the component automatically repaints itself and, if appropriate, resizes itself. "

Repainting is more of a concern when you're using a custom component. You aren't doing that, so it doesn't really matter.

More info here: Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing)

Thank you
I'll close this now