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JPanel repaint doesn't work

I have a simple task.
There is a frame. There are two panel in that frame. In second panel there is a button. When user click that button first panel must change its content.
Here is a code:
package test;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
class MyJPanel1 extends JPanel {
MyJPanel1() {
this.add(new JButton("MyJPanel1"));
}
}
class MyJPanel2 extends JPanel {
MyJPanel2() {
this.add(new JButton("MyJPanel2"));
}
}
class MyFrame extends JFrame {
JPanel topPanel = null;
MyFrame() {
super("Test");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLayout(new GridLayout(0, 1, 20, 20));
topPanel = new MyJPanel1();
this.add(topPanel);
JPanel bottomPanel = new JPanel();
this.add(bottomPanel);
JButton button = new JButton("switch");
button.addMouseListener(new MouseClickListener());
bottomPanel.add(button);
this.pack();
this.setVisible(true);
}
class MouseClickListener extends MouseAdapter {
#Override
public void mouseClicked(MouseEvent e) {
topPanel = new MyJPanel2();
System.out.println("switch");
topPanel.invalidate();
topPanel.validate();
topPanel.repaint();
MyFrame.this.invalidate();
MyFrame.this.validate();
MyFrame.this.repaint();
}
}
}
public class Test {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new MyFrame();
}
});
}
}
But that don't work. After I click on button I see text in console, but first panel remain the same. I read that I must use invalidate() validate() and repaint() methods and I did, but it isn't help.
Any help would be appreciated.

If you want to "switch" panels then you should be using a CardLayout. The CardLayout allows 2 (or more) components to share the same space in a container but only one is ever visible at a time.
Read the section from the Swing tutorial on How to Use CardLayout for more information and working examples.

In your mouseClicked() method you create a new topPanel, but you don't do anything with it. Perhaps you meant to remove the original topPanel from myFrame, create a new topPanel, and then add the new toipPanel to myFrame.
Note that this may not be the best strategy (creating a new topPanel).

Adding JPanel to another JPanel in a different class

I'm trying to add a JPanel to another JPanel from another class. The program does not longer throw an error and all methods have been run, but the new panel just has a black screen. A basic version of the program looks as follows:
package ninjadragon;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class NinjaDragon extends JFrame implements ActionListener{
public JPanel panelMain;
public JPanel panelTurnBase;
public static void main(String[] args) {
NinjaDragon();
}
public static void NinjaDragon() {
NinjaDragon frame;
frame = new NinjaDragon();
frame.CreateMenuScreen();
JFrame.setDefaultLookAndFeelDecorated(true);
frame.setSize(750, 750);
frame.show();
frame.setResizable(false);
frame.pack();
}
private void CreateMenuScreen() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container window = getContentPane();
panelMain =new JPanel();
panelMain.setPreferredSize(new Dimension(750,750));
panelMain.setBackground(Color.BLACK);
panelMain.setLayout (new FlowLayout());
window.add(panelMain);
PanelTop();
PanelButtons();
PanelIcon();
}
#Override
public void actionPerformed(ActionEvent event) {
Object eventSource = event.getSource();
if (eventSource == buttonStart) {
panelMain.removeAll();
TurnBase TB = new TurnBase();
TB.CreateTurnBase();
}
}
The other class looks something like this:
public void CreateTurnBase() {
panelMain=new JPanel();
panelTurnBase =new JPanel();
setLayout(new FlowLayout());
setPreferredSize(new Dimension(750,750));
setBackground(Color.BLUE);
panelTurnBase.setLayout (new FlowLayout());
panelMain.add(panelTurnBase);
System.out.println("1");
PanelTurnBaseTop();
PanelGameScreen();
PanelTurnBaseBottom();
repaint();
revalidate();
buttonAttack = new JButton("Attack");
buttonAttack.addActionListener(this);
panelTurnBase.add(buttonAttack);
System.out.println("2");
}

The reason the panel has "just a black screen" is because you dont add anything to it, and you tell it to have a black screen.
i.e
panel.setBackground(Color.BLACK);
You never actually do anything to that first panel inside of any of those methods, which I can assume based on your representation of your second "class" (it's a method). Hence why it stays black.
You say:
panelMain=new JPanel();
panelTurnBase =new JPanel();
You're creating new JPanels every time and just call them panelMain and they just sit inside of that method, never leaving. You either need to return a JPanel or give it a JPanel as an argument.
The program is doing exactly what you tell it to do.
Also, do not compare Objects like this:
eventSource == buttonStart
You should use:
eventSource.equals(buttonStart);

Putting multiple JPanels inside a JTabbed pane

I've looked around a while and also played around trying to add multiple panels to a JTabbedPane.
My question is: Is it possible to add the same Jpanel to multiple TabbedPanes. Everything way that I tried, it doesn't seem to work correctly. This is how it it works.
public MainGUI() {
JMenuBar menuBar = new JMenuBar();
setJMenuBar(menuBar);
JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP);
getContentPane().add(tabbedPane, BorderLayout.CENTER);
JEditorPane instructionalEditorPane = new JEditorPane();
tabbedPane.addTab("Instructional", instructionalEditorPane);
JPanel codePanel = new JPanel();
JPanel drawPanel = new JPanel();
JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, codePanel, drawPanel);
splitPane.setResizeWeight(0.75);
tabbedPane.addTab("Code Panel", splitPane);
JEditorPane unifiedInstPane = new JEditorPane();
JPanel unifiedCodePanel = new JPanel();
JPanel unifiedDrawPanel = new JPanel();
JSplitPane unifiedSplitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, unifiedCodePanel, unifiedDrawPanel);
unifiedSplitPane.setResizeWeight(0.75);
JSplitPane unifiedPanel = new JSplitPane(JSplitPane.VERTICAL_SPLIT,unifiedInstPane, unifiedSplitPane);
unifiedPanel.setResizeWeight(0.40);
tabbedPane.addTab("Unified Tab", unifiedPanel);
}
What I would like to do is just add the instructionalEditorPane and the splitPane to multiple tabbedPanes but when I do I loose the original Individual tabbedPanes. If I have to I can do it this way but I would then have to write to both the unifiedInstPane & the instructionalEditorPane to keep them updated. I would also have to do this for the 2 splitPanes which have the codePanel and drawPanels embedded. This will make it harder to keep all the panels in sync.
Any suggestions?

"Is it possible to add the same Jpanel to multiple TabbedPanes." -- no. You can only add a component to one container at a time. Your JPanels should share models but use unique components. The model will likely be a non-GUI class of your creation.
For example, here's a very simplistic rendering of my recommendations:
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import javax.swing.*;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;
public class MainGui2 extends JPanel {
private static final int TAB_COUNT = 3;
private JTabbedPane tabbedPane = new JTabbedPane();
private PlainDocument doc = new PlainDocument();
private Action btnAction = new ButtonAction("Button");
public MainGui2() {
for (int i = 0; i < TAB_COUNT; i++) {
tabbedPane.add("Tab " + (i + 1), createPanel(doc, btnAction));
}
setLayout(new BorderLayout());
add(tabbedPane);
}
private JPanel createPanel(PlainDocument doc, Action action) {
JTextArea textArea = new JTextArea(doc);
textArea.setColumns(40);
textArea.setRows(20);
JPanel panel = new JPanel();
panel.add(new JScrollPane(textArea));
panel.add(new JButton(action));
return panel;
}
private class ButtonAction extends AbstractAction {
public ButtonAction(String title) {
super(title);
}
#Override
public void actionPerformed(ActionEvent evt) {
try {
String text = "Button Pressed!\n";
doc.insertString(doc.getLength(), text, null);
} catch (BadLocationException e) {
e.printStackTrace();
}
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("MainGui2");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new MainGui2());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Better would be to create a formal model class that gets injected into each view, each tabbed pane's individual panes.
Edit
You state in comment:
Yes I can fix that by making calls to the instances but then I'm back to my original problem of having to make calls to each instance to affect a change in all the panel. Say for example I have a drawing panel and I need to call repaint(), I would have to make a call to 2 different instances to get both tabbedPanes to update. Is there any way around this?
Yes, the solution is to use an MVC, or model-view-control, structure. Your model holds your overall program logic, the views are what the user sees, and the control interacts between the two.
Consider having your model notify either the control or the views that its been changed, and then this stimulates a repaint an all observer views.

JFrame removing JPanels and adding a new JPanel

I currrently have a SwingWorker that sends a HTTP Request and I override the SwingWorker's done() method to change contents in a JFrame. I want to basically remove everything and add a new members panel on the JFrame depending on the values returned from the Server.
Now, the problem I am facing is that when I invoke the following methods below on the JFrame, it doesn't remove anything from the JFrame nor does it change it's contents contained within the Frame.
//TODO: Investigate why JFrame content pane won't repaint.
f.removeAll();
//Pass the frame f reference only into MainDisplay, it doesn't actually do anything apart from allowing a class to add a JMenuBar on the JFrame.
f.add(new MainDisplay(f));
f.getContentPane().invalidate();
f.getContentPane().validate();
f.getContentPane().repaint();
The current fix I have is this below but I would rather change the contents of the JFrame rather then loading a new one up.
f.dispose();
f=new ApplicationFrame();
I've looked through previous answers on here and on Google and some state use validate() or invalidate() whilst calling repaint() to repaint the JFrame.
Any suggestions/help would be much appreciated.
Edit: I think I am going to debug more since there must be something else going wrong.

for example
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class MyFrame extends JFrame {
private static final long serialVersionUID = 1L;
public MyFrame() {
final JPanel parentPanel = new JPanel();
parentPanel.setLayout(new BorderLayout(10, 10));
final JPanel childPanel1 = new JPanel();
childPanel1.setBackground(Color.red);
childPanel1.setPreferredSize(new Dimension(300, 40));
final JPanel childPanel2 = new JPanel();
childPanel2.setBackground(Color.blue);
childPanel2.setPreferredSize(new Dimension(800, 600));
JButton myButton = new JButton("Add Component ");
myButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
parentPanel.remove(childPanel1);
parentPanel.add(childPanel2, BorderLayout.CENTER);
parentPanel.revalidate();
parentPanel.repaint();
pack();
}
});
setTitle("My Empty Frame");
setLocation(10, 200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
parentPanel.add(childPanel1, BorderLayout.CENTER);
parentPanel.add(myButton, BorderLayout.SOUTH);
add(parentPanel);
pack();
setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
MyFrame myFrame = new MyFrame();
}
});
}
}

You are trying to repaint()/validate() the ContentPane. Did you try doing same on the JFrame?
You can also try JFrame#pack().

modification of your code
f.setContentPane(new MainDisplay(f));
f.getContentPane().invalidate();
f.getContentPane().validate();
f.getContentPane().repaint();

You may try using Frame.pack() again it worked for me. Or try one od those following methods:
Frame.setOpaque(false);
Frame.setEnabled(false);
Frame.setVisible(false);
Frame.removeAll();

Does Container.getComponents() return references to the original components?

I'm using Container.getComponents() to get an array of Components stored inside the Container. I'm then modifying one of these Components (which happens to be a JLabel), but the changes are not showing on the GUI.
So I'm thinking maybe the method creates new instances of each Component which prevents me from making changes to the original component?
Here's my code:
Component[] components = source.getComponents();
if(components.length >= 2) {
if(components[1] instanceof JLabel) {
JLabel htmlArea = (JLabel) components[1];
htmlArea.setText("<html>new changes here</html>");
htmlArea.revalidate();
}
}

It is either another problem outside of the code, or you are doing this from the wrong thread.
Any changes on Swing components should be done in the event dispatch thread. Often is it most easy to surround the changing code with EventQueue.invokeLater(...) (or SwingUtilities.invokeLater, this is the same).
And make sure your component is actually visible on the screen.

There is no need to revalidate() or repaint() anything (unless you are doing something really strange)!
Where is your SSCCE that demonstrates your problem???
It works fine for me:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class TabbedPaneLabel extends JFrame
{
JTabbedPane tabbedPane;
public TabbedPaneLabel()
{
tabbedPane = new JTabbedPane();
add(tabbedPane);
tabbedPane.addTab("First", createPanel("<html>label with text</html>"));
tabbedPane.addTab("Second", createPanel("another label"));
JButton remove = new JButton("Change Label on first tab");
add(remove, BorderLayout.SOUTH);
remove.addActionListener( new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
Component[] components = tabbedPane.getComponents();
JPanel panel = (JPanel)components[0];
JLabel label = (JLabel)panel.getComponent(0);
String date = new Date().toString();
label.setText("<html>" + date + "</html>");
}
});
}
private JPanel createPanel(String text)
{
JPanel panel = new JPanel();
panel.add( new JLabel(text) );
return panel;
}
public static void main(String args[])
{
TabbedPaneLabel frame = new TabbedPaneLabel();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.setSize(300, 200);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}