Develop Reference

BorderLayout combined with FlowLayout: JTextArea ruins GUI (Java Swing)

I use a BorderLayout combined with a FlowLayout, which works perfectly when I set up the BorderLayout.NORTH. However, in the CENTER area I would like to add a JTextArea (to print out console), but when I create a panel, add JTextArea, after adding a panel to BorderLayout.CENTER nothing appears and became grey. I have tried several combinations and tricks, also I have checked several forum posts without luck. Here is my very simplified code (should run flawlessly, I have commented the problematic part if you remove the comment the bug present):
public static void main(String[] args) {
blogGUI();
}
public static void blogGUI() {
JFrame frame = new JFrame("test");
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setVisible(true);
frame.setSize(700, 500);
frame.setLayout(new BorderLayout()); //a frame BorderLayout elrendezésü
JPanel panel1 = new JPanel();
//panel.setBounds(0,0,700,500);
panel1.setBackground(new java.awt.Color(255,255,255));
panel1.setVisible(true);
panel1.setSize(new Dimension(140, 30));
JPanel panel2 = new JPanel();
//panel.setBounds(0,0,700,500);
panel2.setBackground(new java.awt.Color(255,255,255));
panel2.setVisible(true);
panel2.setSize(new Dimension(140, 30));
JButton btNewEntry = new JButton("New Post");
JButton btModifyEntry = new JButton("Modify");
JButton btDeleteEntry = new JButton("Delete");
JButton btShowEntries = new JButton("List");
JButton btExit = new JButton("Exit");
JLabel lbFile = new JLabel("Open Blog:");
JLabel lbFilePath = new JLabel("Nothing selected...");
JButton btFileOpen = new JButton("Open");
btNewEntry.setPreferredSize(new Dimension(100,30));
btModifyEntry.setPreferredSize(new Dimension(100,30));
btDeleteEntry.setPreferredSize(new Dimension(100,30));
btShowEntries.setPreferredSize(new Dimension(100,30));
btExit.setPreferredSize(new Dimension(100,30));
lbFile.setPreferredSize(new Dimension(100,30));
lbFilePath.setPreferredSize(new Dimension(310,30));
btFileOpen.setPreferredSize(new Dimension(100,30));
panel1.add(btNewEntry);
panel1.add(btModifyEntry);
panel1.add(btDeleteEntry);
panel1.add(btShowEntries);
panel1.add(btExit);
panel2.add(lbFile);
panel2.add(btFileOpen);
panel2.add(lbFilePath);
JPanel cpanelNorth = new JPanel();
cpanelNorth.setBackground(new java.awt.Color(135,206,250));
cpanelNorth.setLayout(new FlowLayout());
cpanelNorth.setPreferredSize(new Dimension(500, 95));
cpanelNorth.add(panel1);
cpanelNorth.add(panel2);
frame.add(cpanelNorth, BorderLayout.NORTH);
/*Something wrong here! From this point, if this uncommented ruins the gui.*/
JPanel panel3 = new JPanel();
panel3.setLayout(new FlowLayout());
//panel.setBounds(0,0,700,500);
panel3.setBackground(new java.awt.Color(255,255,255));
//panel3.setVisible(true);
//panel3.setPreferredSize(new Dimension(30, 30));
JTextArea textArea = new JTextArea("Welcome to...!");
//textArea.setPreferredSize(new Dimension(50,50));
textArea.setBackground(new java.awt.Color(255,0,0));
panel3.add(textArea);
frame.add(panel3, BorderLayout.CENTER);

Hi Andrew Thompson and user16320675, Thanks for the quick help, this solved my issue. How can I further improve the quality the code? I had to put only one setPrefferedSize() at the JTextArea, all other places I removed (without this the window shrinks to zero)
I reduced my code
image: https://ibb.co/Xj7tYKf
I have removed allsetPrefferedSize()
I put frame.setVisible(true) at the end, and also frame.pack() at the end
Here is my code:
package bloggui;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class Start {
public static void main(String[] args) {
blogGUI();
}
public static void blogGUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
JPanel panel1 = new JPanel();
panel1.setBackground(new java.awt.Color(255,255,255));
JPanel panel2 = new JPanel();
panel2.setBackground(new java.awt.Color(255,255,255));
JButton btNewEntry = new JButton("New Post");
JButton btModifyEntry = new JButton("Modify");
JButton btDeleteEntry = new JButton("Delete");
JButton btShowEntries = new JButton("List");
JButton btExit = new JButton("Exit");
JLabel lbFile = new JLabel("Open Blog:");
JLabel lbFilePath = new JLabel("Nothing selected...");
JButton btFileOpen = new JButton("Open");
panel1.add(btNewEntry);
panel1.add(btModifyEntry);
panel1.add(btDeleteEntry);
panel1.add(btShowEntries);
panel1.add(btExit);
panel2.add(lbFile);
panel2.add(btFileOpen);
panel2.add(lbFilePath);
JPanel cpanelNorth = new JPanel();
cpanelNorth.setBackground(new java.awt.Color(135,206,250));
cpanelNorth.setLayout(new FlowLayout());
cpanelNorth.add(panel1);
cpanelNorth.add(panel2);
frame.add(cpanelNorth, BorderLayout.NORTH);
frame.pack();
JPanel panel3 = new JPanel();
panel3.setLayout(new FlowLayout());
panel3.setBackground(new java.awt.Color(135,206,250));
JTextArea textArea = new JTextArea("Welcome to...!");
textArea.setBackground(new java.awt.Color(255,255,255));
textArea.setPreferredSize(new Dimension(620, 400)); //Must not use setPreferredSize() [I must use it only once here!]
panel3.add(textArea);
frame.add(panel3, BorderLayout.CENTER);
frame.pack(); //Must be at the end
frame.setVisible(true); //Must be at the end
}
}

Java JFrame: Windows Layout & Embed

I need to define a layout for a Jframe Window, as in the picture above.
Below is my approach.
A Picture from my resources folder (/resources/...jpg) embed inside the middle(main).
Top, Bottom, Left and Right divided in four parts, whereas their content is a labeled button stretched, so I can map some methods on it later, that change the picture inside the main container.
I tried to display the picture, but I get the result you see in my screenshot. I can't see it inside my main container and I receive no error message.
I don't know if this is because of my wrong approach of using JFrame.
Below you can see my code, I'd be happy if you could help me solving my wrong design layout pattern too.
MyFrame.java
package ms0.gui;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
public class MyFrame extends JFrame {
public MyFrame () {
setTitle("This is an example title");
setSize(600,600);
setLocation(750,640);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
//Main Container
Container mainContainer = this.getContentPane();
mainContainer.setLayout(new BorderLayout(8,6));
mainContainer.setBackground(Color.BLUE);
this.getRootPane().setBorder(BorderFactory.createMatteBorder(4, 4, 4, 4, Color.green));
//JButton Positions
JButton topButton = new JButton("Oben");
JButton bottomButton = new JButton("Unten");
JButton leftButton = new JButton("Links");
JButton rightButton = new JButton("Rechts");
//Panel Top
JPanel topPanel = new JPanel();
topPanel.setBorder(new LineBorder(Color.BLACK, 3));
topPanel.setBackground(Color.ORANGE);
topPanel.setLayout(new FlowLayout(5));
topPanel.add(topButton);
mainContainer.add(topPanel, BorderLayout.NORTH);
//Panel Middle
JPanel middlePanel = new JPanel();
middlePanel.setBorder(new LineBorder(Color.black, 3));
middlePanel.setLayout(new FlowLayout(4,4,4));
middlePanel.setBackground(Color.cyan);
//Grid Panel Right
JPanel rightPanel = new JPanel();
rightPanel.setLayout(new FlowLayout(4,4,4));
rightPanel.setBorder(new LineBorder(Color.black, 3));
rightPanel.setBackground(Color.GREEN);
rightPanel.add(rightButton);
//Grid Panel Left
JPanel gridPanel = new JPanel();
gridPanel.setLayout(new GridLayout(4,1,5,5));
gridPanel.setBorder(new LineBorder(Color.black, 3));
gridPanel.setBackground(Color.red);
gridPanel.add(leftButton);
//Center Box
JLabel label = new JLabel("Center Box", SwingConstants.CENTER);
label.setOpaque(true);
label.setBorder(new LineBorder(Color.black,3));
middlePanel.add(gridPanel);
mainContainer.add(label);
mainContainer.add(middlePanel, BorderLayout.WEST);
mainContainer.add(rightPanel, BorderLayout.EAST);
//Panel Bottom
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new FlowLayout(3));
bottomPanel.add(bottomButton);
bottomPanel.setBackground(Color.magenta);
bottomPanel.setBorder(new LineBorder(Color.BLUE, 3));
mainContainer.add(bottomPanel, BorderLayout.SOUTH);
//Siegel
String filepath = "/resources/siegel.jpg";
int picWidth = 150;
int picHeight = 150;
ImageIcon image1 = new ImageIcon(getClass().getResource(filepath));
//Image scaledImage = img.getScaledInstance(picWidth, picHeight, Image.SCALE_DEFAULT);
//ImageIcon icon = new ImageIcon(scaledImage);
mainContainer.add(new JButton(image1));
}
}

So, as a very basic example, nothing but BorderLayout
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.border.EmptyBorder;
public class MyFrame extends JFrame {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
MyFrame frame = new MyFrame();
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public MyFrame() {
setTitle("This is an example title");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(new BorderLayout());
add(new JButton("Top button (stretched)"), BorderLayout.NORTH);
add(new JButton("Left button (stretched)"), BorderLayout.WEST);
add(new JButton("Right button (stretched)"), BorderLayout.EAST);
add(new JButton("Bottom button (stretched)"), BorderLayout.SOUTH);
JLabel label = new JLabel("Picture");
label.setBorder(new EmptyBorder(100, 100, 100, 100));
add(label);
}
}
Remember, simple is often best.
Now, if you absolutely, positively must have the label/picture in another container, you can simply make use of GridBagLayout, as it will centre the child component(s) by default, for example...
JLabel label = new JLabel("Picture");
label.setBorder(new EmptyBorder(100, 100, 100, 100));
// Automatic center position
JPanel mainPane = new JPanel(new GridBagLayout());
mainPane.add(label);
add(mainPane);
And you don't have to use EmptyBorder. GridBagLayout will allow to supply insets which will do the same thing

Why is BorderLayout not displaying properly with multiple layers?

I am setting up a UI for a blackjack helper program and while I know its not the most beautiful way to do things, it makes sense.
The layering for what seems to be the upper layers is not working properly. Any suggestions?
The left should have four layers, as should the middle and the right side should have two layers between the keypad and the enter buttons. Image is attached below.
import java.util.*;
import java.lang.*;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
// main method, runs the program
class BlackjackHelper
{
public static void main(String\[\] args)
{
Frame21 game = new Frame21();
//pop window with rules of game
}
}
// JFrame Construction
class Frame21 extends JFrame
{
// create needed components of program
JLabel questionDisplay = new JLabel("What is your first card?");
JLabel actionDisplay = new JLabel("Enter your first card");
JLabel dealerCardText = new JLabel("Dealer's Card:");
JLabel dealerCardDisplay = new JLabel("N/A");
JLabel handOneText = new JLabel("Hand One:");
JLabel handOneDisplay = new JLabel("N/A");
JLabel handTwoText = new JLabel("Hand Two:");
JLabel handTwoDisplay = new JLabel("N/A");
JLabel statsText = new JLabel("Win %:");
JLabel statsDisplay = new JLabel("N/A");
JButton aceButton = new JButton("A");
JButton twoButton = new JButton("2");
JButton threeButton = new JButton("3");
JButton fourButton = new JButton("4");
JButton fiveButton = new JButton("5");
JButton sixButton = new JButton("6");
JButton sevenButton = new JButton("7");
JButton eightButton = new JButton("8");
JButton nineButton = new JButton("9");
JButton tenButton = new JButton("10");
JButton faceButton = new JButton("F");
JButton clearButton = new JButton("C");
JButton standButton = new JButton("Stand");
JButton hitButton = new JButton("Hit");
JButton doubleButton = new JButton("Double");
JButton splitButton = new JButton("Split");
JButton winButton = new JButton("Win");
JButton loseButton = new JButton("Lose");
JButton resetButton = new JButton("Reset All");
JButton enterButton = new JButton("Enter");
public Frame21()
{
// JFrame - the main area of the program
JFrame frame = new JFrame("Blackjack Helper");
// JPanel right - the rightside of the program
JPanel rightSide = new JPanel();
JPanel rightNorthSide = new JPanel();
rightNorthSide.setLayout(new GridLayout(3,4));
rightNorthSide.add(aceButton);
rightNorthSide.add(twoButton);
rightNorthSide.add(threeButton);
rightNorthSide.add(fourButton);
rightNorthSide.add(fiveButton);
rightNorthSide.add(sixButton);
rightNorthSide.add(sevenButton);
rightNorthSide.add(eightButton);
rightNorthSide.add(nineButton);
rightNorthSide.add(tenButton);
rightNorthSide.add(faceButton);
rightNorthSide.add(clearButton);
JPanel rightSouthSide = new JPanel();
rightSouthSide.add(resetButton, BorderLayout.WEST);
rightSouthSide.add(enterButton, BorderLayout.EAST);
rightSide.add(rightNorthSide, BorderLayout.NORTH);
rightSide.add(rightSouthSide, BorderLayout.SOUTH);
frame.add(rightSide, BorderLayout.EAST);
// JPanel Center - the center of the program
JPanel center = new JPanel();
JPanel centerNorth = new JPanel();
centerNorth.add(questionDisplay, BorderLayout.NORTH);
centerNorth.add(actionDisplay, BorderLayout.SOUTH);
JPanel centerSouth = new JPanel();
JPanel centerSouthNorth = new JPanel();
centerSouthNorth.add(dealerCardText, BorderLayout.WEST);
centerSouthNorth.add(dealerCardDisplay, BorderLayout.EAST);
JPanel centerSouthSouth = new JPanel();
JPanel centerSouthSouthWest = new JPanel();
centerSouthSouthWest.add(handOneText, BorderLayout.NORTH);
centerSouthSouthWest.add(handOneDisplay, BorderLayout.SOUTH);
JPanel centerSouthSouthEast = new JPanel();
centerSouthSouthEast.add(handTwoText, BorderLayout.NORTH);
centerSouthSouthEast.add(handTwoDisplay, BorderLayout.SOUTH);
centerSouthSouth.add(centerSouthSouthWest, BorderLayout.WEST);
centerSouthSouth.add(centerSouthSouthEast, BorderLayout.EAST);
centerSouth.add(centerSouthNorth, BorderLayout.NORTH);
centerSouth.add(centerSouthSouth, BorderLayout.SOUTH);
center.add(centerNorth, BorderLayout.NORTH);
center.add(centerSouth, BorderLayout.SOUTH);
frame.add(center, BorderLayout.CENTER);
// JPanel left - the center of the program
JPanel left = new JPanel();
JPanel leftNorth = new JPanel();
JPanel leftNorthNorth = new JPanel();
JPanel leftNorthSouth = new JPanel();
JPanel leftSouth = new JPanel();
JPanel leftSouthNorth = new JPanel();
JPanel leftSouthSouth = new JPanel();
leftNorthNorth.add(standButton, BorderLayout.WEST);
leftNorthNorth.add(hitButton, BorderLayout.EAST);
leftNorthSouth.add(doubleButton, BorderLayout.WEST);
leftNorthSouth.add(splitButton, BorderLayout.EAST);
leftNorth.add(leftNorthNorth, BorderLayout.NORTH);
leftNorth.add(leftNorthSouth, BorderLayout.SOUTH);
leftSouthNorth.add(statsText, BorderLayout.WEST);
leftSouthNorth.add(statsDisplay, BorderLayout.EAST);
leftSouthSouth.add(winButton, BorderLayout.WEST);
leftSouthSouth.add(loseButton, BorderLayout.EAST);
leftSouth.add(leftSouthNorth, BorderLayout.NORTH);
leftSouth.add(leftSouthSouth, BorderLayout.SOUTH);
left.add(leftNorth, BorderLayout.NORTH);
left.add(leftSouth, BorderLayout.SOUTH);
frame.add(left, BorderLayout.WEST);
frame.setSize(1600, 200);
frame.setVisible(true);
frame.setResizable(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

The layering for what seems to be the upper layers is not working properly. Any suggestions? The left should have four layers.
A BorderLayout does not "layer".
Only a single component can be added to each of the 5 areas of the BorderLayout.
So, yes, you can create a JPanel and add multiple components to that panel, and then add the panel to an area of the BorderLayout.
JPanel rightSouthSide = new JPanel();
rightSouthSide.add(resetButton, BorderLayout.WEST);
rightSouthSide.add(enterButton, BorderLayout.EAST);
However, the above code is incorrect. The default layout manager of a JPanel is the FlowLayout. So specifying BorderLayout constraints does nothing (and is very confusing).
If by "layers" you mean "rows", then you need to use a panel with a different layout manage. Maybe you can use a BoxLayout to add rows of panels.
Overall, your approach to creating panels with different components is valid, the problem is you also need to use the appropriate layout manager for each of your child panels.
Read the Swing tutorial on Layout Managers for more information about how each of the layout managers work.

usage of BorderLayout

I am having a problem with BorderLayout, that was set to the green JPanel side. It does not display elements on the EAST in a row order. Do I have to combine this with GridBagLayout ? Could someone advice me how should I tackle this problem?
Basically the problem is of displaying objects inside green area below when I am using
Current layout:
My aim is to achieve this layout:
public class GUILayout {
public static void main(String[] args) {
JFrame jf = new JFrame();
JButton jbO = new JButton("CSIS0396");
JButton jbl = new JButton("Final");
JButton jb2 = new JButton("2010");
JButton jb3 = new JButton("Exam");
JPanel panel = new JPanel();
JPanel panel2 = new JPanel();
JButton object_btn = new JButton("Object");
JButton oriented_btn = new JButton("Oriented");
JButton programming_btn = new JButton("Programming");
JButton and_btn = new JButton("and");
JButton java_btn = new JButton("Java");
BorderLayout layout = new BorderLayout();
panel.setLayout(layout);
panel2.setLayout(layout);
panel.add(BorderLayout.CENTER,object_btn);
panel.add(BorderLayout.WEST,oriented_btn);
panel.add(BorderLayout.WEST,programming_btn);
panel.add(BorderLayout.WEST,and_btn);
panel.add(BorderLayout.WEST,java_btn);
panel2.add(BorderLayout.NORTH, jbO);
panel2.add(BorderLayout.SOUTH, jb2);
panel2.add(BorderLayout.WEST, jbl);
panel2.add(BorderLayout.EAST, jb3);
panel.setBackground(Color.GREEN);
panel2.setBackground(Color.RED);
jf.getContentPane().add(panel);
jf.getContentPane().add(panel2, BorderLayout.EAST);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setSize(400, 300);
jf.setVisible(true);
}
}

don't share same layout for multiple component and use box layout for left panel to positioning buttons
import java.awt.BorderLayout;
import java.awt.Color;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class GUILayout {
public static void main(String[] args) {
JFrame jf = new JFrame();
JButton jbO = new JButton("CSIS0396");
JButton jbl = new JButton("Final");
JButton jb2 = new JButton("2010");
JButton jb3 = new JButton("Exam");
JPanel panel = new JPanel();
JPanel panel2 = new JPanel();
JButton object_btn = new JButton("Object");
JButton oriented_btn = new JButton("Oriented");
JButton programming_btn = new JButton("Programming");
JButton and_btn = new JButton("and");
JButton java_btn = new JButton("Java");
BorderLayout layout = new BorderLayout();
panel2.setLayout(layout);
panel.setLayout( new BoxLayout(panel, BoxLayout.PAGE_AXIS));
panel.add(object_btn);
panel.add(oriented_btn);
panel.add(programming_btn);
panel.add(and_btn);
panel.add(java_btn);
panel2.add(BorderLayout.NORTH, jbO);
panel2.add(BorderLayout.SOUTH, jb2);
panel2.add(BorderLayout.WEST, jbl);
panel2.add(BorderLayout.EAST, jb3);
panel.setBackground(Color.GREEN);
panel2.setBackground(Color.RED);
jf.setLayout(new BorderLayout());
jf.getContentPane().add(panel ,BorderLayout.WEST);
jf.getContentPane().add(panel2, BorderLayout.EAST);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setSize(400, 300);
jf.setVisible(true);
}
}

The first problem is that you're having your panels share a layout. You must use a new BorderLayout for each of them.
The second problem is that a BorderLayout can only have one component in each constraint position. When you try to add multiple components to the WEST position, each one replaces the one that was previously in that position:
panel.add(BorderLayout.WEST,oriented_btn);
// Implicitly removes oriented_btn from panel
panel.add(BorderLayout.WEST,programming_btn);
// Implicitly removes programming_btn from panel
panel.add(BorderLayout.WEST,and_btn);
// Implicitly removes and_btn from panel
panel.add(BorderLayout.WEST,java_btn);
The solution is to put them in their own container, such as a Box or a JPanel with a GridLayout:
Box box = Box.createVerticalBox();
// Or:
//JComponent box = new JPanel(new GridLayout(0, 1));
box.add(oriented_btn);
box.add(programming_btn);
box.add(and_btn);
box.add(java_btn);
panel.add(BorderLayout.WEST, box);

Resizable Swing layout with buttons arranged according to variable dimensions

I would like to make a layout using Java Swing which looks like the following drawing.
(source: braun-abstatt.de)
On the left is a JPanel which is drawn through paintComponent() in a way that the graphics automatically scale when the window is resized. (The question isn't about that panel. That one's already done.)
Now I need some buttons (the black boxes, added in Photoshop for the drawing) to the right of the JPanel mentioned before. The height of the reddish areas at the top and bottom, next to which there should be just empty space, is calculated along the lines of CONSTANT_FACTOR * getHeight(). Next to each compartment on the left, there should be a group of buttons, lined up to the center of the respective compartment (see the blue lines).
The JPanel containing the buttons knows about the CONSTANT_FACTOR and the number of compartments, so it should be possible to feed this information into a layout manager.
Which layout manager would I best use to achieve this layout? I've read about all the different layout managers, but I can't quite figure out which one or which combination of them best fits in this case.

For example, by use of a different LayoutManager, a very easy and simple container, takes no more than 15-20 minutes:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
public class ThinLineFrame {
private JFrame frame = new JFrame();
private JScrollPane scrollPane;
private JPanel panel = new JPanel();
private JPanel panelNorth = new JPanel();
private JPanel panelCenter = new JPanel();
private JPanel panelCenterCh1 = new JPanel();
private JPanel panelCenterCh2 = new JPanel();
private JPanel panelCenterCh3 = new JPanel();
private JPanel panelCenterCh4 = new JPanel();
private JPanel panelCenterCh5 = new JPanel();
private JPanel panelSouth = new JPanel();
public ThinLineFrame() {
panelNorth.setBackground(Color.red.darker());
panelNorth.setPreferredSize(new Dimension(80, 30));
//
panelCenter.setBackground(Color.darkGray);
panelCenter.setLayout(new GridLayout(5, 1, 2, 2));
//
panelCenterCh1.setLayout(new BorderLayout());
JButton panelCenterCh1Button = new JButton();
panelCenterCh1.add(panelCenterCh1Button, BorderLayout.CENTER);
//
JButton panelCenterCh2Button1 = new JButton();
JButton panelCenterCh2Button2 = new JButton();
panelCenterCh2.setLayout(new GridLayout(2, 1, 2, 2));
panelCenterCh2.add(panelCenterCh2Button1);
panelCenterCh2.add(panelCenterCh2Button2);
//
JButton panelCenterCh3Button1 = new JButton();
JButton panelCenterCh3Button2 = new JButton();
panelCenterCh3.setLayout(new GridLayout(2, 1, 2, 2));
panelCenterCh3.add(panelCenterCh3Button1);
panelCenterCh3.add(panelCenterCh3Button2);
//
JButton panelCenterCh4Button1 = new JButton();
JButton panelCenterCh4Button2 = new JButton();
panelCenterCh4.setLayout(new GridLayout(2, 1, 2, 2));
panelCenterCh4.add(panelCenterCh4Button1);
panelCenterCh4.add(panelCenterCh4Button2);
//
panelCenterCh5.setLayout(new BorderLayout());
JButton panelCenterCh5Button = new JButton();
panelCenterCh5.add(panelCenterCh5Button, BorderLayout.CENTER);
//
panelCenter.add(panelCenterCh1);
panelCenter.add(panelCenterCh2);
panelCenter.add(panelCenterCh3);
panelCenter.add(panelCenterCh4);
panelCenter.add(panelCenterCh5);
//
panelSouth.setBackground(Color.red.darker());
panelSouth.setPreferredSize(new Dimension(80, 30));
//
panel.setLayout(new BorderLayout(2, 2));
panel.add(panelNorth, BorderLayout.NORTH);
panel.add(panelCenter, BorderLayout.CENTER);
panel.add(panelSouth, BorderLayout.SOUTH);
//
scrollPane = new JScrollPane(panel);
frame.add(scrollPane, BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(80, 600));
frame.setLocation(100, 150);
frame.pack();
frame.setVisible(true);
}
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
ThinLineFrame dlg = new ThinLineFrame();
}
});
}
}

You should try looking at MigLayout. It's a super flexible LayoutManager that is also very simple.
The code would look something like:
MigLayout layout = new MigLayout("flowy");
panel.setLayoutManager(layout);
panel.add(button1);
panel.adD(button2);
etc..
Try adding debug, flowy to the constructor to get a visual idea of what is going on.

GBC without an anchor, just with plain vanilla GridBagConstraints and preferred size.
Centered JButton with fixed size:
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class MainWithFixSize {
public static void main(String[] argv) throws Exception {
JFrame frame = new JFrame();
Container container = frame.getContentPane();
GridBagLayout gbl = new GridBagLayout();
container.setLayout(gbl);
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 1;
gbc.gridy = 1;
JButton component = new JButton();
component.setPreferredSize(new Dimension(25, 25));
gbl.setConstraints(component, gbc);
container.add(component);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(40, 90));
frame.pack();
frame.setVisible(true);
}
private MainWithFixSize() {
}
}