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How can I align elements in JPanels / JFrames?

I am completely unaccustomed to using the GUI in java, so I am having trouble figuring out how to align everything I need. I have panels in my JFrame that I need to align (one on the left, one on the right) and several buttons on one of the panels that I need to focus on the panel. Here is my code.

package application;

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.io.*;
import java.nio.*;
import java.util.*;

public class Main extends JPanel 
{
    public static void main(String[] args)
    { 
        //set the ui to the native OS
        try
        { 
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        }catch(ClassNotFoundException | InstantiationException | IllegalAccessException 
        | UnsupportedLookAndFeelException e)                                   
        {
        }

        JFrame frame = new JFrame("Application Name");
        Menu menu = new Menu();
        JPanel iconPanel = new JPanel();
        final JPanel grid = new JPanel(new FlowLayout());
        JButton firewallButton = new JButton("Firewall");
        JButton networkButton = new JButton("Network");
        JButton printerButton = new JButton("Printer");

        int iconPanelSizeX;
        int iconPanelSizeY;
        int gridSizeX;
        int gridSizeY;
        int gridPosition;

        //frame setting
        frame.setSize(800, 600);
        frame.setMinimumSize(new Dimension(800, 600));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

        //add grid and iconPanel JPanels to the frame
        frame.add(iconPanel);
        iconPanel.add(firewallButton);
        iconPanel.add(networkButton);
        iconPanel.add(printerButton);
        frame.add(grid);        

        //iconPanel settings
        iconPanel.setBorder(BorderFactory.createLoweredSoftBevelBorder());
        iconPanel.setBackground(Color.gray);
        iconPanel.setLayout(new FlowLayout());
        iconPanel.setSize(new Dimension(100, 600));
        iconPanel.setVisible(true);

        //grid setting
        grid.setBackground(Color.red);
        grid.setSize(new Dimension(700, 600));
        grid.setVisible(true);

        //this is for resizing components when the user resizes the window
        int counter = 0;
        while(counter == 0)
        {
            firewallButton.setSize(new Dimension(iconPanel.getWidth(), 50));
            networkButton.setSize(new Dimension(iconPanel.getWidth(), 50));
            printerButton.setSize(new Dimension(iconPanel.getWidth(), 50));
            iconPanelSizeX = frame.getWidth() / 10;
            iconPanelSizeY = frame.getHeight();
            gridSizeX = (frame.getWidth() / 10) * 9;
            gridSizeY = frame.getHeight();
            iconPanel.setSize(new Dimension(iconPanelSizeX, iconPanelSizeY));
            grid.setSize(new Dimension(gridSizeX, gridSizeY));
        }
    }
}

As you can see, the second JPanel (grid) does not align with the right side of the frame, and the buttons inside iconTray are also not centered. I understand that these are probably simple layout fixes, but I don't know where to start.

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4 answers

JFrame GridLayout 1 2- .

frame.setLayout(new GridLayout(1,2,3,3)); //3,3 are gaps
frame.add(grid);
frame.add(iconPanel);

FlowLayout, JPanels:

:

grid.setLayout(new FlowLayout()); //Centered components

grid.setLayout(new FlowLayout(FlowLayout.LEFT,3,3)); //Components aligned to left

grid.setLayout(new FlowLayout(FlowLayout.RIGHT,3,3)); //Components aligned to right

:

enter image description here

, :

  • setXXXSize() ;

  • setSize(); JFrame, pack();;

  • setVisible(true); ;

"" :

import javax.swing.*;
import java.awt.*;


public class Main extends JPanel
{
    public static void main(String[] args)
    {
        JFrame frame = new JFrame("Application Name");
        JPanel iconPanel = new JPanel();
        JPanel grid = new JPanel(new FlowLayout());
        JButton firewallButton = new JButton("Firewall");
        JButton networkButton = new JButton("Network");
        JButton printerButton = new JButton("Printer");


        frame.add(iconPanel);
        iconPanel.add(firewallButton);
        iconPanel.add(networkButton);
        iconPanel.add(printerButton);
        grid.setBackground(Color.GREEN);

        frame.setLayout(new GridLayout(1,2,3,3));
        frame.add(grid);
        frame.add(iconPanel);


        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}
+7

?

Box WEST BorderLayout:

enter image description here

import java.awt.*;
import javax.swing.*;

/** @see http://stackoverflow.com/a/14927280/230513 */
public class Main {

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

            @Override
            public void run() {
                display();
            }
        });
    }

    private static void display() throws HeadlessException {
        JFrame frame = new JFrame("Application Name");
        JButton firewallButton = new JButton("Firewall");
        JButton networkButton = new JButton("Network");
        JButton printerButton = new JButton("Printer");

        //iconPanel settings
        Box iconPanel = new Box(BoxLayout.Y_AXIS);
        iconPanel.add(firewallButton);
        iconPanel.add(networkButton);
        iconPanel.add(printerButton);
        iconPanel.setBackground(Color.gray);
        iconPanel.setVisible(true);
        frame.add(iconPanel, BorderLayout.WEST);

        //grid setting
        JPanel grid = new JPanel() {

            @Override
            // arbitrary placeholder size
            public Dimension getPreferredSize() {
                return new Dimension(320, 230);
            }
        };
        grid.setBackground(Color.red);
        frame.add(grid, BorderLayout.CENTER);

        //frame setting
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}
+5

. , API. , , , , . , , API, API- Layout Manager, .

+2

JFrame, ( , ) , . .

I understand that these are probably simple layout fixes, but I don’t have a clue where to start.

Use a more complex layout than the simple FlowLayoutone you are actually using. I suggest you use

  • GridBagLayout
  • BoxLayout

Mark references here

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