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JPanel and JLabels stretching to fit size of parent, regardless of maximum size - java wordle clone

In the class that extends JFrame, I have the following code:
public Frame() {
setTitle("WORDLE");
// creates all containers
Container mainContainer = getContentPane();
JPanel gridContainer = new JPanel();
JPanel optionsContainer = new JPanel();
// sets size of main frame
setSize(WIDTH, 900);
// sets background size and background colors of all containers
gridContainer.setBackground(GameTheme.BACKGROUND); // TODO: add message label inside of gridContainer below grid JPanel
gridContainer.setPreferredSize(new Dimension(WIDTH - 150, 500));
gridContainer.setMaximumSize(new Dimension(WIDTH - 150, 500));
gridContainer.setLayout(new BorderLayout(10, 0));
optionsContainer.setBackground(GameTheme.BACKGROUND);
optionsContainer.setPreferredSize(new Dimension(WIDTH, 100));
// creates grid with boxes for letter
grid = new JPanel();
grid.setLayout(new GridLayout(6, 5, 5, 5));
grid.setPreferredSize(new Dimension(WIDTH - 150, 400));
grid.setMaximumSize(new Dimension(WIDTH - 150, 400));
grid.setBackground(GameTheme.BACKGROUND);
createBoxes();
// JLabel for messages
JLabel alertLabel = new JLabel("test");
alertLabel.setOpaque(true);
alertLabel.setForeground(GameTheme.WHITE);
alertLabel.setBackground(GameTheme.BACKGROUND);
// listens for presses in the JFrame, with the Game class implementing the method for the keypress event
addKeyListener(new Game(boxes));
// lays out all containers and their sub-containers
// title label at top, grid container at center, options container at bottom
mainContainer.setLayout(new BorderLayout());
mainContainer.add(createTitle(), BorderLayout.NORTH); // createTitle returns a JLabel
mainContainer.add(gridContainer, BorderLayout.CENTER);
mainContainer.add(optionsContainer, BorderLayout.SOUTH);
gridContainer.add(grid, BorderLayout.NORTH);
gridContainer.add(alertLabel, BorderLayout.SOUTH);
// boilerplate frame configuration
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setLocationRelativeTo(null);
pack();
setVisible(true);
}
public void createBoxes() {
// initializes 2d array for letter boxes
boxes = new LetterBox[6][5];
// populates 2d array and adds boxes to the grid container
for (int r = 0; r < 6; r++) {
for (int c = 0; c < 5; c++) {
LetterBox letterBox = new LetterBox(r, c);
boxes[r][c] = letterBox;
grid.add(letterBox.getBox());
}
}
}
I have set a maximum size on all of the components within gridContainer, and even on the gridContainer itself, yet the JLabels are still stretching to take up the size of the GUI. Can someone help me figure out why this is happening, and how I can fix it?
To make the problem clear, here are some images that show what I want vs what I am getting:
Expected:
Actual:
I tried to describe as clearly as possible please comment and let me know if there is anything I need to clarify.

Don't keep playing with the preferred/minimum/maximum sizes of parent panels and the frame. Each panel should be able to calculate its preferred size based on the preferred size of the components added to the panel. So you add components to a panel and the panels to the frame, then you pack the frame and everything will be displayed at the proper size.
So in your case you can use a GridLayout for your "gridContainer". Then you add your JLabels to the gridContainer. For your LetterBox component you should use a "monospaced" Font so all characters will take the same space. Then you can initialize your label with a default value of " " to give the label a size.
This size will be too small so you will then also want to add an EmptyBorder to the LetterBox. So in the constructor you can add something like:
setBorder( new EmptyBorder(10, 10, 10, 10) );
Now the LeterBox can calculates its preferred size correctly and the "gridContainer" will be able to calculate its preferred size correctly.
However, when you add the panel the the CENTER of the BorderLayout, the BorderLayout will attempt to resize each component to fill the space available in the frame. To prevent this you can use a "wrapper" panel:
JPanel wrapper = new JPanel(); // uses FlowLayout by default
wrapper.add( gridContainer );
mainContainer.add(wrapper, BorderLayout.CENTER);
//mainContainer.add(gridContainer, BorderLayout.CENTER);
Now if the frame is resized the extra space will go to the wrapper panel NOT the gridContainer.

In case you would like to relax a little the requirement of the frame being unresizable, here follow some implementations which restrict the maximum size of the grid to the preferred, but do not restrict the minimum. As a result in both implementations the grid will not get bigger than its preferred size, making it possible for the user to enlarge the frame and empty spaces to appear by the LayoutManagers used to fill the remaining space.
The minimum size of the grid is not restricted however, just in case the user wants to resize the frame to a smaller size. This is supposed to be an extra feature, although if you want to disable it the easiest way would be to uncomment the frame.setMinimumSize(frame.getSize()); line in each implementation.
Both implementations take into account the sizes of the grid.
BoxLayout implementation:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class BoxMain {
private static void createAndShowGUI() {
final int rows = 6, cols = 15;
final JPanel grid = new JPanel(new GridLayout(rows, 0, 5, 5));
for (int row = 0; row < rows; ++row)
for (int col = 0; col < cols; ++col)
grid.add(new JLabel(Integer.toString(row * cols + col), JLabel.CENTER));
final Dimension sz = grid.getPreferredSize();
grid.setMaximumSize(sz);
grid.setMinimumSize(new Dimension(0, sz.height));
final JPanel box = new JPanel();
box.setLayout(new BoxLayout(box, BoxLayout.X_AXIS));
box.add(Box.createGlue());
box.add(grid);
box.add(Box.createGlue());
final JPanel mainPanel = new JPanel(new BorderLayout());
mainPanel.add(box, BorderLayout.CENTER);
mainPanel.add(new JLabel("Alert label", JLabel.CENTER), BorderLayout.PAGE_END);
final JFrame frame = new JFrame("Wordle");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
//frame.setMinimumSize(frame.getSize());
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(BoxMain::createAndShowGUI);
}
}
SpringLayout implementation:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Spring;
import javax.swing.SpringLayout;
import javax.swing.SwingUtilities;
public class SpringMain {
private static void createAndShowGUI() {
final int rows = 6, cols = 15;
final JPanel grid = new JPanel(new GridLayout(rows, 0, 5, 5));
for (int row = 0; row < rows; ++row)
for (int col = 0; col < cols; ++col)
grid.add(new JLabel(Integer.toString(row * cols + col), JLabel.CENTER));
grid.setMaximumSize(grid.getPreferredSize());
grid.setMinimumSize(new Dimension());
final SpringLayout layout = new SpringLayout();
final JPanel spring = new JPanel(layout);
spring.add(grid);
final Spring flexible = Spring.constant(0, 0, Short.MAX_VALUE);
layout.putConstraint(SpringLayout.WEST, grid, flexible, SpringLayout.WEST, spring);
layout.putConstraint(SpringLayout.EAST, spring, flexible, SpringLayout.EAST, grid);
layout.putConstraint(SpringLayout.NORTH, grid, flexible, SpringLayout.NORTH, spring);
layout.putConstraint(SpringLayout.SOUTH, spring, flexible, SpringLayout.SOUTH, grid);
final JPanel mainPanel = new JPanel(new BorderLayout());
mainPanel.add(spring, BorderLayout.CENTER);
mainPanel.add(new JLabel("Alert label", JLabel.CENTER), BorderLayout.PAGE_END);
final JFrame frame = new JFrame("Wordle");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
//frame.setMinimumSize(frame.getSize());
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(SpringMain::createAndShowGUI);
}
}

Resize JFrame to JPanels inside JLayeredPane

I'm working on a Swing GUI using the JLayeredPane. The JFrame has a JLayeredPane which contains two JPanels. Later I want to display some components in the JPanels, I cut this part of the code to make it shorter for you.
How do I resize the JFrame to the sizes of the JPanels? frame.pack() does not work and without the line setting the preferred size the GUI will show with minimal size.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
public class TestGUI {
private JFrame frame;
private JLayeredPane layeredPane;
private JPanel panelBottom;
private JPanel panelTop;
private MainMenuBar menuBar;
public TestGUI() {
// panel bottom:
panelBottom = new JPanel();
panelBottom.setSize(1000, 500);
panelBottom.setBackground(new Color(0, 100, 0, 100));
panelBottom.setLayout(new GridBagLayout());
// panel top:
panelTop = new JPanel();
panelTop.setSize(950, 450);
panelTop.setBackground(new Color(0, 0, 100, 100));
panelTop.setLayout(new GridBagLayout());
// layered pane:
layeredPane = new JLayeredPane();
layeredPane.add(panelBottom, 1);
layeredPane.add(panelTop, 0);
// frame building:
frame = new JFrame();
menuBar = new MainMenuBar();
frame.setJMenuBar(menuBar);
frame.setLayout(new BorderLayout());
frame.setPreferredSize(new Dimension(1100, 600)); // <-- Without this the GUI will be very small
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(layeredPane, BorderLayout.CENTER);
frame.pack(); // <-- does not work!
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
new TestGUI();
}
}
EDIT: I could just change the preferred size line to fit the biggest JPanel, but i ask the question because I want the JFrame to resize depending on the size of the JPanels dynamically.

As suggested in How to Use Layered Panes: Laying Out Components in a Layered Pane, "Although a layered pane has no layout manager by default, you can still assign a layout manager to the layered pane." Use OverlayLayout, seen here, for overlapping panels.
Alternatively, use JInternalFrame, which does allow you to pack() the internal frames individually, as shown here and here.

Using JLayeredPane to add multiple JPanels to a JPanel

I am trying to add multiple panels to another panel. I want them to be on top of each other so I'm using JLayeredPane. I've added a button to each one. Two buttons should appear when it works.
import java.awt.Color;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
public class PanelTest {
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel mainPanel = new JPanel();
JPanel panel1 = new JPanel();
JPanel panel2 = new JPanel();
JLayeredPane layers = new JLayeredPane();
mainPanel.add(layers);
panel2.setOpaque(false);
panel1.setOpaque(false);
panel1.setVisible(true);
panel2.setVisible(true);
panel1.add(new JButton("1111111111"));
panel2.add(new JButton("2"));
frame.setContentPane(mainPanel);
layers.add(panel1, new Integer(2));
layers.add(panel2, new Integer(3));
frame.setVisible(true);
frame.setSize(500, 500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
Only the grey background of the mainPanel is visible. What am I doing wrong?

When adding a component to a JLayeredPane, you're essentially adding the component to a null layout using container. This means that you must fully specify both the component's size and its position, often solving both with a setBounds(...) call. Call this on panel1 and panel2, for example:
panel1.setBounds(10, 10, 100, 100);
panel2.setBounds(70, 70, 100, 100);
Edit:
setting bounds didn't make any difference
Setting the size (bounds) is required but you still have an additional problem.
You are adding the JLayeredPane to a JPanel which uses a FlowLayout. By default a FlowLayout respects the preferred size of the component added to it. Since JLayeredPane uses a null layout its preferred size is (0, 0) so there is nothing to paint.
Two solutions:
You don't need the JPanel, just use: frame.setContentPane(layers);
If you really want to use the panel then you need to change the layout manager: JPanel mainPanel = new JPanel( new BorderLayout());

JLayeredPane white background next to component

Experimenting with layered panes here and I'm having a problem. I have two JPanels. I'm adding them both to a JLayeredPane - panel1 is big enough to take up the whole space, while panel2 is smaller and centered using FlowLayout. The problem is that with JLayeredPane, the background next to panel2 seems to be painted white when I add it. Here's a picture to illustrate. panel1 is blue, panel2 is red:
As you can see, the bottom part of the panel1 is still painted, but for some reason the sides are just white. The panel2 is 700 pixels wide and centered, while the frame is 800 pixels wide, so it's definitely not a problem with that. Here's the entire class:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
public class Errortest extends JFrame {
public static void main(String[] args) {
//Creating frame and setting the JLayeredPane as contentpane
Errortest frame = new Errortest();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLayeredPane pane = new JLayeredPane();
pane.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0));
pane.setPreferredSize(new Dimension(800,600));
frame.setContentPane(pane);
frame.pack();
//Creating panels
JPanel panel1 = new JPanel();
panel1.setPreferredSize(new Dimension(800,600));
panel1.setBackground(Color.BLUE);
JPanel panel2 = new JPanel();
panel2.setPreferredSize(new Dimension(700,500));
panel2.setBackground(Color.RED);
pane.add(panel1, new Integer(0));
pane.add(panel2, new Integer(1));
frame.setVisible(true);
}
}
Hopefully that wasn't too confusing. From what I can tell, the white background comes from the JFrame itself, since when I do frame.setBackground(Color.YELLOW); it turns yellow.

If you add a component to a JLayeredPane, it's like adding it to a null layout using container: you must fully specify the component's size and position.
import java.awt.*;
import javax.swing.*;
public class ErrorTest extends JFrame {
public static void main(String[] args) {
// Creating frame and setting the JLayeredPane as contentpane
ErrorTest frame = new ErrorTest();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JComponent pane = new JLayeredPane();
//pane.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0)); // Take out FlowLayout
pane.setPreferredSize(new Dimension(800, 600));
frame.setContentPane(pane);
// Creating panels
JPanel panel1 = new JPanel();
panel1.setBackground(Color.BLUE);
panel1.setBounds(0, 0, 800, 600); // <<<---- Set Bounds
JPanel panel2 = new JPanel();
panel2.setBackground(Color.RED);
panel2.setBounds(50, 0, 700, 500); // <<---- Set Bounds
pane.add(panel1, new Integer(1));
pane.add(panel2, new Integer(2));
frame.pack();
frame.setVisible(true);
}
}

I believe I found out what the problem is. Has to do with the answer here:
JLayeredPane not respecting layers
You need a layout manager which understands the Z-Axis. The default layout managers don't understand the Z-Axis of the JLayeredPane.
So it's the FlowLayout that's messing me up. I'll just use absolute positioning for my project and use setBounds() to make sure the red panel ends up in the middle. Otherwise I'd have to look into custom layout managers I suppose.

How do i allow my Jslider to fit inside my JPanel?

I am programming a small application and have run into a big bump. I am stuck on why the JSlider won't allow me to add it to the JPanel.
When the last line of code reads:
"add.(slider);"
the JSlider covers the entire JPanel. Is this correct and I need to resize my JSlider somehow? Or, have I made a mistake with the code and are not making the Jslider visible within the Jpanel?
Here's my code:
package atmosfile;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JSlider;
import java.awt.*;
public class Main extends JFrame {
private static final long serialVersionUID = 1L;
public Main() {
super("Package Choice");
setSize(800, 600);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLocationRelativeTo(null);
JPanel panel = new JPanel();
panel.setLayout(new FlowLayout(1, 100, 500));
panel.add(new JButton("Package 1"));
panel.add(new JButton("Package 2"));
panel.add(new JButton("Package 3"));
add(panel);
JSlider slider = new JSlider();
slider.setLayout(new FlowLayout(1, 100, 200));
slider.setMajorTickSpacing(5);
slider.setPaintTicks(true);
slider.setSize(200, 200);
slider.setVisible(true);
panel.add(slider);
}
}
Thanks in advance for any help its most appreciated!

The horizontal gap of your FlowLayout is so large that it "pushes" the JSlider component out of the drawable area of the frame. Reducing it brings it back in into view again. Also would recommend avoiding the use of magic numbers (1 = FlowLayout.CENTER):
panel.setLayout(new FlowLayout(FlowLayout.CENTER, 50, 500));