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Layout Problem in Java - set a 20%opaque Panel on Bottom of JFrame

Well, actually I have a Layout problem in java Swing. I simply want to add a JPanel on the bottom of a Frame - a coding snipplet that might be done with every web based language in about 5 Minutes. Not so in Java. I tried to add a jPanel to a jFrame, that Contains a jContentPane, set the size of the jPanel to what I need and to repaint and revalidate the jFrame, as well as setting the LayOutManager to null.
Java shows me in this case a full-width jPanel, that fills my whole jFrame.
Therefore I tried another approach: I divided my jPanel in a fully transparent jPanel on top and a 20%opaque jPanel on the bottom. Still it didn't work out as expected.
Since then I tried to resize the child jPanels of my new Panel and the Panel as well and tried to repaint and revalidate the jFrame. Without any effect.
Despite of my efforts, java still shows me a full sized 20%opaque jPanel on the whole jFrame, that now contains another 20%opaque jPanel on Top.
I know that this whole problem is caused by the LayoutManager, Java useless per Default. However, it is not an option to set the LayoutManager to null or even change the LayoutManager of our jFrame, because that would lead us to refactor the whole functionality of our tiny app we worked on for several weeks.
public void showUndoPanel() {
System .out.println("Show Undo Panel");
JPanel myPanel = new JPanel(null);
JPanel glassPanel = new JPanel();
JPanel ContentPanel = new JPanel();
JLabel myJLabel = new JLabel("Great Job!");
myPanel.setBackground(new Color(255,122,122,100));
glassPanel.setSize(650, 550);
glassPanel.setBackground(new Color(255,122,122,100));
myPanel.add(glassPanel);
ContentPanel.setSize(650, 30);
ContentPanel.setBackground(new Color(255,122,122,20));
ContentPanel.add(myJLabel);
myPanel.revalidate();
myPanel.repaint();
undoPanel = myPanel;
myJFrame.add(undoPanel);
myJFrame.revalidate();
}
What I expected:
What it actually does:

Well, I solved the problem by using a BoxLayoutManager and a RigidArea. In case if anyone else may encounter that problem again in the future, I decided to provide the code for this simple solution.
public void showUndoPanel() {
System .out.println("Show Undo Panel");
JPanel myPanel = new JPanel(null);
JPanel glassPanel = new JPanel();
JPanel ContentPanel = new JPanel();
JLabel myJLabel = new JLabel("Great Job!");
myPanel.setBackground(new Color(255,255,255,0));
myPanel.setLayout(new BoxLayout(myPanel, BoxLayout.PAGE_AXIS));
glassPanel.setSize(650, 650);
glassPanel.setBounds(0,0,650,550);
glassPanel.setBackground(new Color(255,122,122,0));
myPanel.add(glassPanel);
myPanel.add(Box.createRigidArea(new Dimension(0,450)));
ContentPanel.setSize(650, 30);
ContentPanel.setBounds(0,750,650,30);
ContentPanel.setBackground(new Color(255,122,122,20));
ContentPanel.add(myJLabel);
myPanel.add(ContentPanel);
myPanel.revalidate();
myPanel.repaint();
undoPanel = myPanel;
myJFrame.add(undoPanel);
myJFrame.revalidate();
}
Now it behaves as expected:

BorderLyout would make it easier to implement.
Note the comments in the following mre:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Main {
private static JFrame myJFrame;
public static void main(String[] args) {
myJFrame = new JFrame();
myJFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
myJFrame.setLocationRelativeTo(null);
showUndoPanel();
myJFrame.pack();
myJFrame.setVisible(true);
}
public static void showUndoPanel() {
JPanel myPanel = new JPanel();
myPanel.setBackground(new Color(255,255,255,0));
myPanel.setLayout(new BorderLayout());
JPanel glassPanel = new JPanel(); //uses FlowLayout by default
//glassPanel.setSize(650, 650); //use preferred size
glassPanel.setPreferredSize(new Dimension(650, 650));
//glassPanel.setBounds(0,0,650,550); //no need to set bounds. bounds are set by the layout manager
glassPanel.setBackground(new Color(255,122,122,0));
myPanel.add(glassPanel, BorderLayout.CENTER);
JPanel contentPanel = new JPanel(); //uses FlowLayout by default
//contentPanel.setSize(650, 30);//use preferred size
contentPanel.setPreferredSize(new Dimension(650, 30));
//contentPanel.setBounds(0,750,650,30); //no need to set bounds. bounds are set by the layout manager
contentPanel.setBackground(new Color(255,122,122,20));
JLabel myJLabel = new JLabel("Great Job!");
contentPanel.add(myJLabel);
myPanel.add(contentPanel, BorderLayout.SOUTH);
myJFrame.add(myPanel);
}
}

JFrame will not load new screen

I have a class that extends JFrame and works by adding in 2 panels with BoxLayout buttons, and one JTabbedPane in the center which displays graphs.
I want one of the buttons to remove all current components in the frame and add new ones.
Here are the methods used.
private void createAndShowGraphs() {
ImageIcon createImageIcon(lsuLettersPath); //simple png file to fill one tab
final JTabbedPane jtp = new JTabbedPane();
JLabel iconLabel = new JLabel();
iconLabel.setOpaque(true);
jtp.addTab(null, icon, iconLabel);
//Here is where the errors begin
JPanel menu = new JPanel();
menu.setLayout(new BoxLayout(menu, BoxLayout.Y_AXIS));
//I want this button to remove all components currently in the JFrame and replace them with new components specified in the createAndShowIntro() method
menu.add(new JButton(new AbstractAction("Intro Pane") {
public void actionPerformed(ActionEvent e) {
//I've also tried putting removeAll in the Intro method
removeAll();
createAndShowIntro();
}
}));
add(jtp, BorderLayout.CENTER);
add(menu, BorderLayout.WEST);
pack();
setVisible(true);
}
private void createAndShowIntro() {
System.out.println("Made it to Intro");
//all I want is a blank JLabel with the String "test" to show up
JPanel test = new JPanel();
test.setLayout(new BorderLayout());
JLabel label = new JLabel();
label.setText("test");
label.setHorizontalAlignment(SwingConstants.CENTER);
label.setVerticalAlignment(SwingConstants.CENTER);
test.add(label);
add(test, BorderLayout.CENTER);
test.revalidate();
label.revalidate();
validate();
test.repaint();
label.repaint();
repaint();
pack();
setVisible(true);
}
When I call createAndShowGraphs() in main() and then hit the 'Intro' button, everything freezes and nothing is actually removed. I know it makes it the Intro method because of the "Made it to Intro" string output to the terminal.
I've tried all kinds of combinations of invalidate(), validate(), revalidate(), repaint() on the labels and on the frame itself. Really frustrated because I don't know how else I'm going to be able to display 3 different screens to switch back and forth between while only actually displaying one at a time.
Thanks for your time.

Problems with BorderLayout() in Java

I've tried a lot of different ways, but I will explain two and what was happening (no error messages or anything, just not showing up like they should or just not showing up at all):
First, I created a JPanel called layout and set it as a BorderLayout. Here is a snippet of how I made it look:
JPanel layout = new JPanel();
layout.setLayout(new BorderLayout());
colorChoice = new JLabel("Choose your color: ");
layout.add(colorChoice, BorderLayout.NORTH);
colorBox = new JComboBox(fireworkColors);
colorBox.addActionListener(this);
layout.add(colorBox, BorderLayout.NORTH);
In this scenario what happens is they don't show up at all. It just continues on with whatever else I added.
So then I just tried setLayout(new BorderLayout()); Here is a snippet of that code:
setLayout(new BorderLayout());
colorChoice = new JLabel("Choose your color: ");
add(colorChoice, BorderLayout.NORTH);
colorBox = new JComboBox(fireworkColors);
colorBox.addActionListener(this);
add(colorBox, BorderLayout.NORTH);
In this scenario they are added, however, the width takes up the entire width of the frame and the textfield (not shown in the snippet) takes up basically everything else.
Here is what I have tried:
setPreferredSize() & setSize()
Is there something else that I am missing? Thank you.
I also should note that this is a separate class and there is no main in this class. I only say this because I've extended JPanel instead of JFrame. I've seen some people extend JFrame and use JFrame, but I haven't tried it yet.

You created a JPanel, but didn't add it to any container. It won't be visible until it is added to something (a JFrame, or another panel that is in a frame somewhere up the hierarhcy)
You added two components to the same position in the BorderLayout. The last one added is the one that will occupy that position.
Update:
You do not need to extend JFrame. I never do, instead I always extend JPanel. This makes my custom components more flexible: they can be added in another panel, or they can be added to a frame.
So, to demonstrate the problem I will make an entire, small, program:
public class BadGui
{
public static void main(String[] argv)
{
final JFrame frame = new JFrame("Hello World");
final JPanel panel = new JPanel();
panel.add(new JLabel("Hello"), BorderLayout.NORTH);
panel.add(new JLabel("World"), BorderLayout.SOUTH);
frame.setVisible(true);
}
}
In this program I created a panel, but did not add it to anything so it never becomes visible.
In the next program I will fix it by adding the panel to the frame.
public class FixedGui
{
public static void main(String[] argv)
{
final JFrame frame = new JFrame("Hello World");
final JPanel panel = new JPanel();
panel.add(new JLabel("Hello"), BorderLayout.NORTH);
panel.add(new JLabel("World"), BorderLayout.SOUTH);
frame.getContentPane().add(panel);
frame.setVisible(true);
}
}
Note that in both of these, when I added something to the panel, I chose different layout parameters (one label I put in 'North' and the other in 'South').

Here is an example of a JPanel with a BorderLayout that adds a JPanel with a button and label to the "North"
public class Frames extends JFrame
{
public Frames()
{
JPanel homePanel = new JPanel(new BorderLayout());
JPanel northContainerPanel = new JPanel(new FlowLayout());
JButton yourBtn = new JButton("I Do Nothing");
JLabel yourLabel = new JLabel("I Say Stuff");
homePanel.add(northContainerPanel, BorderLayout.NORTH);
northContainerPanel.add(yourBtn);
northContainerPanel.add(yourLabel);
add(homePanel);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setLocationRelativeTo(null);
setExtendedState(JFrame.MAXIMIZED_BOTH);
setTitle("Cool Stuff");
pack();
setVisible(true);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(Frames::new);
}
}

The below suggestion is assuming that your extending JFrame.
Testing
First of all, without seeing everything, theres always a numerous amount of things you can try.
First off, after you load everything, try adding this in (Again, assuming your extending JFrame:
revalidate();
repaint();
I add this into my own Swing projects all the time, as it refreshes and checks to see that everything is on the frame.
If that doesn't work, make sure that all your JComponent's are added to your JPanel, and ONLY your JPanel is on your JFrame. Your JFrame cannot sort everything out; the JPanel does that.
JPanel window = new JPanel();
JButton button = new JButton("Press me");
add(window);
window.add(button); // Notice how it's the JPanel that holds my components.
One thing though, you still add your JMenu's and what-not through your JFrame, not your JPanel.

Multiple panels in JFrame

The useless Layout Manager guy is back again, I just can't seem to get my head around these darn layouts and make them work the way I want.
Anyway, I want to have a JFrame which has one large panel at the top (I call it a header) which runs from the left to right side of the frame at the north part of the frame, then four panels below it, two just below the header and two below those, and finally a "footer" panel, basically the same as the header panel, only at the south part of the frame.
Like this:
I had code which had the four middle panels working fine, but the header panel just messed everything up, and I have since been testing with the demo layout manager code for GridBagLayout, GridLayout again and BoxLayout. I can't getting any to work as I want.
For the aware of you here, you will probably notice I've already had a question related to this, and if having two similar questions are not allowed, please make me aware and I will move this to my previous question and this can be closed.
public Shop() {
shopUI = new JFrame("Shop Menu");
shopUI.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
shopUI.setBounds(100, 100, 700, 500);
shopUI.setResizable(false);
allPanels = new JPanel();
headerPanel = new JPanel();
headerPanel.setLayout(new BorderLayout());
headerPanel.setBackground(Color.cyan);
mainPanel = new JPanel();
mainPanel.setLayout(new GridLayout(2,2));
topLeft = new JPanel();
topLeft.setBackground(Color.pink);
topRight = new JPanel();
topRight.setBackground(Color.black);
bottomLeft = new JPanel();
bottomLeft.setBackground(Color.green);
bottomRight = new JPanel();
bottomRight.setBackground(Color.blue);
footerPanel = new JPanel();
footerPanel.setLayout(new BorderLayout());
footerPanel.setBackground(Color.magenta);
mainPanel.add(topLeft);
mainPanel.add(topRight);
mainPanel.add(bottomLeft);
mainPanel.add(bottomRight);
allPanels.add(headerPanel, BorderLayout.NORTH);
allPanels.add(footerPanel, BorderLayout.SOUTH);
allPanels.add(mainPanel);
shopUI.add(allPanels);
shopUI.setVisible(true);
}

I suggest learning about border layout.
for what you want, put the header in the NORTH of the border panel, and the footer in the SOUTH. How you do your other panels depends a bit on what you want them to do; if you always want them to be the same size as each other, you can use a gridlayout for them; if not, you can use boxlayout to lay either the two pairs horizontally or the two pairs vertically, again depending on what you want them to do when the frame resizes.
I think using layout managers is simplified by deciding what you want to happen in the first place, including what happens when the frame is resized. That's a large part of what layouts are all about, anyway -- what stretches, what lines up, etc.
Anyway. what you have there looks like classic BorderLayout to me. Let us know if you need further help. Incidentally, BorderLayout is default for JFrame...
edit...
this will get more interesting when you put something in the panels...
package simpleborderlayout;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main
{
public static void main(String[] args)
{
Main main = new Main(args);
main.go();
}
public Main(String ... args)
{}
public void go()
{
JPanel headerPanel = getPanel(Color.RED);
JPanel footerPanel = getPanel(Color.BLUE);
JPanel p1 = getPanel(Color.GRAY);
JPanel p2 = getPanel(Color.GRAY);
JPanel p3 = getPanel(Color.GRAY);
JPanel p4 = getPanel(Color.GRAY);
GridLayout gridLayout = new GridLayout(2,2);
JPanel middlePanel = new JPanel(gridLayout);
middlePanel.add(p1);
middlePanel.add(p2);
middlePanel.add(p3);
middlePanel.add(p4);
JFrame mainFrame = new JFrame();
mainFrame.add(headerPanel, BorderLayout.NORTH);
mainFrame.add(middlePanel, BorderLayout.CENTER);
mainFrame.add(footerPanel, BorderLayout.SOUTH);
mainFrame.pack();
mainFrame.setVisible(true);
}
private JPanel getPanel(Color c)
{
JPanel result = new JPanel();
result.setBorder(BorderFactory.createLineBorder(c));
return result;
}
}

Java Swing spacing between objects

I have a Java program where i would prefer if i could get a very specific layout.
This is what I get:
JLabel JToggleButon JLabel JToggleButon
This is what I want:
JLabel JToggleButon
JLabel JToggleButon
This is the code:
package Main;
import javax.swing.*;
import java.awt.FlowLayout;
import java.awt.GridBagLayout;
public class SystemWindow {
static JFrame window = new JFrame("System statistics");
static JToggleButton button = new JToggleButton("Push me");
static JLabel status = new JLabel("Status: ");
static JLabel status2 = new JLabel("Status: ");
static JToggleButton button2 = new JToggleButton("Push me");
static FlowLayout layout = new FlowLayout();
public static void openWindow(){
window.setLayout(new GridBagLayout());
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.add(status);
window.add(button);
window.add(status2);
window.add(button2);
window.setSize(100, 100);
window.pack();
window.setSize(200,70);
window.setVisible(true);
while(true){
status.setText("Status: "+button.isSelected());
status2.setText("Status: "+button2.isSelected());
}
}
}
p.s: Wrote the code in eclipse.

you can use GridLayout where you can specify rows, columns and spacings
i.e. add a jpanel with gridlayout and add these elements inside this panel
new JPanel(new GridLayout(2,2,5,5));
first parameter is the rows, second the columns and the others are the horizontal and vertical spacing between controls
I guess this works
JPanel panel = new JPanel(new GridLayout(2,2,5,5));
window.add(panel);
panel.add(status);
panel.add(button);
panel.add(status2);
panel.add(button2);

The behaviour you are getting is the default behaviour for FlowLayout. Read more about it here. Read morea bout layouts here and choose what you prefer.

As you are using GridBayLayout you have to provide some position constraints when adding controls to container. Here you have complete guide. 3rd party layout manager as MigLayout should suit your needs too.
while(true){
status.setText("Status: "+button.isSelected());
status2.setText("Status: "+button2.isSelected());
}
your computer is going to explode thanks to that code :)