Develop Reference

JLayeredPane with JPanel

The problem: I have no control on implementing more into the histogram package, so I create an array of buttons and overlay them on top of the histogram using JLayeredPane. However, I cannot get both the histogram plot and the buttons panels to scale when the JFrame is enlarged or contracted.
The JLayedPane is composed of 2 JPanels, see MWE.
To repeat the issue, just run program and extend JFrame.
I have read the following on SO posts; jlayeredpane-with-gridlayout, jlayeredpane-with-a-layoutmanager, jlayeredpane-not-resizing-with-jframe, resize-jframe-to-jpanels-inside-jlayeredpane, automatic-content-resizing-of-jlayeredpane,
as well as the Oracle page on JLayeredPane which has some examples
As useful as these links were, I still cannot get both JPanels to extend/contract with the JFrame.
Question: Is there a way to get both JPanels in the JLayeredPane to rescale without implementing a new layout? If new layout is needed, would someone please provide a MWE on how to do such?
public class FrameDemo extends JPanel {
private JLayeredPane layeredPane;
private final int width = 800;
private final int height = 800;
private String[] layerStrings = { "Yellow (0)", "Magenta (1)", "Cyan (2)", "Red (3)", "Green (4)", "Blue (5)" };
private Color[] layerColors = { Color.yellow, Color.magenta, Color.cyan, Color.red, Color.green, Color.blue };
public FrameDemo() {
setLayout(new BorderLayout());
init();
addPanels();
add(layeredPane, BorderLayout.CENTER);
}
private void init() {
this.layeredPane = new JLayeredPane();
this.layeredPane.setPreferredSize(new Dimension(width, height));
this.layeredPane.setBorder(BorderFactory.createTitledBorder("Histogram should go here"));
this.layeredPane.setLayout(new BorderLayout());
}
private void addPanels() {
this.layeredPane.add(createHistogramPanel(), BorderLayout.CENTER, new Integer(1));
this.layeredPane.add(createButtonPanel(), BorderLayout.CENTER, new Integer(0));
this.layeredPane.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e) {
Dimension size = layeredPane.getSize(); // get size
createHistogramPanel().setSize(size); // push size through
createButtonPanel().setSize(size); // push size trhough
// otherChildOfLayers.setSize(size); // push size trhough
layeredPane.revalidate(); // revalidate to see updates
layeredPane.repaint(); // "Always invoke repaint after
// revalidate"
}
});
}
private JPanel createHistogramPanel() {
JPanel histpanel = new JPanel();
histpanel.setLayout(new GridLayout(2, 3));
for (int i = 0; i < layerStrings.length; i++) {
JLabel label = createColoredLabel(layerStrings[i], layerColors[i]);
histpanel.add(label);
}
histpanel.setOpaque(false);
histpanel.setBounds(10, 10, width, height);
return histpanel;
}
private JLabel createColoredLabel(String text, Color color) {
JLabel label = new JLabel("");
label.setVerticalAlignment(JLabel.TOP);
label.setHorizontalAlignment(JLabel.CENTER);
label.setOpaque(true);
label.setBackground(color);
label.setForeground(Color.black);
label.setBorder(BorderFactory.createLineBorder(Color.black));
label.setPreferredSize(new Dimension(120, 120));
return label;
}
private JPanel createButtonPanel() {
ButtonGroup buttons = new ButtonGroup();
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(2, 3));
for (int i = 0; i < 6; i++) {
final int placer = i + 1;
JButton freshButton = new JButton();
freshButton.addActionListener(e -> {
System.out.println("Button " + placer + " clicked");
});
freshButton.setText("Button " + (i + 1));
freshButton.setOpaque(true);
freshButton.setContentAreaFilled(false);
freshButton.setBorderPainted(false);
freshButton.setBounds(new Rectangle(132, 75 + (i * 20), 40, 20));
buttonPanel.add(freshButton, null);
buttons.add(freshButton);
}
buttonPanel.setOpaque(false);
buttonPanel.setBounds(10, 10, width, height);
return buttonPanel;
}
private static void createAndShowGUI() {
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JComponent newContentPane = new FrameDemo();
newContentPane.setOpaque(true); // content panes must be opaque
frame.setContentPane(newContentPane);
frame.setLocationRelativeTo(null);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}

Your code won't work because in componentResized you're creating new panels and applying the size to them. You need to resize the existing panels added to the layered pane. This could be done by assigning histogramPanel and buttonPanel as instance variables.

BorderLayout not working JFrame

For some reason I can't get the BorderLayout to set the way it's supposed to. Just would like to know where I'm going wrong.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ColorFactory extends JFrame
{
final int width = 500;
final int height = 300;
private JPanel buttonPanel;
private JPanel radioButtonPanel;
private JLabel msgChangeColor;
public ColorFactory()
{
setTitle("Color Factory");
setSize(width, height);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
createTopPanel();
add(buttonPanel, BorderLayout.NORTH);
createBottomPanel();
add(radioButtonPanel, BorderLayout.SOUTH);
msgChangeColor = new JLabel("Top buttons change the panel color and bottom radio buttons change the text color.");
add(msgChangeColor, BorderLayout.CENTER);
pack();
}
private void createTopPanel()
{
buttonPanel = new JPanel();
setLayout(new FlowLayout());
JButton redButton = new JButton("Red");
redButton.setBackground(Color.RED);
redButton.addActionListener(new ButtonListener());
redButton.setActionCommand("R");
JButton orangeButton = new JButton("Orange");
orangeButton.setBackground(Color.ORANGE);
orangeButton.addActionListener(new ButtonListener());
orangeButton.setActionCommand("O");
JButton yellowButton = new JButton("Yellow");
yellowButton.setBackground(Color.YELLOW);
yellowButton.addActionListener(new ButtonListener());
yellowButton.setActionCommand("Y");
buttonPanel.add(redButton);
buttonPanel.add(orangeButton);
buttonPanel.add(yellowButton);
}
private void createBottomPanel()
{
radioButtonPanel = new JPanel();
setLayout(new FlowLayout());
JRadioButton greenRadioButton = new JRadioButton("Green");
greenRadioButton.setBackground(Color.GREEN);
greenRadioButton.addActionListener(new RadioButtonListener());
greenRadioButton.setActionCommand("G");
JButton blueRadioButton = new JButton("Blue");
blueRadioButton.setBackground(Color.BLUE);
blueRadioButton.addActionListener(new RadioButtonListener());
blueRadioButton.setActionCommand("B");
JButton cyanRadioButton = new JButton("Cyan");
cyanRadioButton.setBackground(Color.CYAN);
cyanRadioButton.addActionListener(new RadioButtonListener());
cyanRadioButton.setActionCommand("C");
radioButtonPanel.add(greenRadioButton);
radioButtonPanel.add(blueRadioButton);
radioButtonPanel.add(cyanRadioButton);
}
private class ButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String actionColor = e.getActionCommand();
if(actionColor.equals("R"))
{
buttonPanel.setBackground(Color.RED);
radioButtonPanel.setBackground(Color.RED);
}
if(actionColor.equals("O"))
{
buttonPanel.setBackground(Color.ORANGE);
radioButtonPanel.setBackground(Color.ORANGE);
}
if(actionColor.equals("Y"))
{
buttonPanel.setBackground(Color.YELLOW);
radioButtonPanel.setBackground(Color.YELLOW);
}
}
}
private class RadioButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String actionTextColor = e.getActionCommand();
if(actionTextColor.equals("G"))
{
msgChangeColor.setForeground(Color.GREEN);
}
if(actionTextColor.equals("B"))
{
msgChangeColor.setForeground(Color.BLUE);
}
if(actionTextColor.equals("C"))
{
msgChangeColor.setForeground(Color.CYAN);
}
}
}
public static void main(String[] args)
{
ColorFactory run = new ColorFactory();
run.setVisible(true);
}
}

The problem is you are changing the layout manager for the frame when you create your top and bottom panels...
private void createTopPanel() {
buttonPanel = new JPanel();
setLayout(new FlowLayout()); // <--- This is call setLayout on the frame
This is why it's dangerous to...
Extend from something like JFrame directly...
Dynamically build components
It's all to easy to lose context and start effecting components you didn't actually want to...

Another problem (besides the one posted by MadProgrammer) is that you add your components to the JFrame itself.
You should add content to the content pane of the frame which you can get by calling JFrame.getContentPane().
Example:
JFrame f = new JFrame("Test");
Container c = f.getContentPane();
c.add(new JButton("In Center"), BorderLayout.CENTER);
c.add(new JButton("At the Bottom"), BorderLayout.SOUTH);
c.add(new JButton("At the Top"), BorderLayout.NORTH);
c.add(new JButton("On the Left"), BorderLayout.WEST);
c.add(new JButton("On the Right"), BorderLayout.EAST);
You can set/change the content panel by calling JFrame.setContentPane(). The default content panel already has BorderLayout so you don't even need to change it nor to set a new panel.

all individual panels are not shown inside root panel

I want to add multiple jpanels to jpanel.So i added a root panel to jscrollpane.and then added all individual jpanels to this root panel.I made jscrollpane's scrolling policy as needed.i.e HORIZONTAL_SCROLLBAR_AS_NEEDED,VERTICAL_SCROLLBAR_AS_NEEDED.
But the problem is all individual panels are not shown inside root panel.
Code:
JScrollPane scPanel=new JScrollPane();
JPanel rootPanel=new JPanel();
rootPanel.setLayout(new FlowLayout());
JPanel indPanel = new JPanel();
rootPanel.add(indPanel);
JPanel indPanel2 = new JPanel();
rootPanel.add(indPanel2);
//.....like this added indPanals to rootPanel.
scPanel.setViewPortView(rootPanel);
//scPanel.setHorizontalScrollPolicy(HORIZONTAL_SCROLLBAR_AS_NEEDED);
And one more thing is, as i scroll the scrollbar the panels are going out of jscrollpane area.
I am not able to see all individual panels,
Please suggest me.
Edit: code snippet from double post:
MosaicFilesStatusBean mosaicFilesStatusBean = new MosaicFilesStatusBean();
DefaultTableModel tableModel = null;
tableModel = mosaicFilesStatusBean.getFilesStatusBetweenDates(startDate, endDate);
if (tableModel != null) {
rootPanel.removeAll();
rootPanel.setLayout(new BoxLayout(rootPanel, BoxLayout.PAGE_AXIS));
for (int tempRow = 0; tempRow < tableModel.getRowCount(); tempRow++) {
int fileIdTemp = Integer.parseInt(tableModel.getValueAt(tempRow, 0).toString());
String dateFromTemp = tableModel.getValueAt(tempRow, 3).toString();
String dateToTemp = tableModel.getValueAt(tempRow, 4).toString();
int processIdTemp = Integer.parseInt(tableModel.getValueAt(tempRow, 5).toString());
int statusIdTemp = Integer.parseInt(tableModel.getValueAt(tempRow, 6).toString());
String operatingDateTemp = tableModel.getValueAt(tempRow, 7).toString();
MosaicPanel tempPanel =
new MosaicPanel(fileIdTemp, dateFromTemp, dateToTemp, processIdTemp, statusIdTemp, operatingDateTemp);
rootPanel.add(tempPanel);
}
rootPanel.revalidate();
}

The main reason, why you couldn't see your JPanel is that you are using FlowLayout as the LayoutManager for the rootPanel. And since your JPanel added to this rootPanel has nothing inside it, hence it will take it's size as 0, 0, for width and height respectively. Though using GridLayout such situation shouldn't come. Have a look at this code example attached :
import java.awt.*;
import javax.swing.*;
public class PanelAddition
{
private void createAndDisplayGUI()
{
JFrame frame = new JFrame("Panel Addition Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setLayout(new GridLayout(0, 1));
JScrollPane scroller = new JScrollPane();
CustomPanel panel = new CustomPanel(1);
contentPane.add(panel);
scroller.setViewportView(contentPane);
frame.getContentPane().add(scroller, BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
for (int i = 2; i < 20; i++)
{
CustomPanel pane = new CustomPanel(i);
contentPane.add(pane);
contentPane.revalidate();
contentPane.repaint();
}
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new PanelAddition().createAndDisplayGUI();
}
});
}
}
class CustomPanel extends JPanel
{
public CustomPanel(int num)
{
JLabel label = new JLabel("" + num);
add(label);
}
#Override
public Dimension getPreferredSize()
{
return (new Dimension(200, 50));
}
}

Don't use FlowLayout for the rootPanel. Instead consider using BoxLayout:
JPanel rootPanel=new JPanel();
// if you want to stack JPanels vertically:
rootPanel.setLayout(new BoxLayout(rootPanel, BoxLayout.PAGE_AXIS));
Edit 1
Here's an SSCCE that's loosely based on your latest code posted:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.util.Random;
import javax.swing.*;
#SuppressWarnings("serial")
public class PanelsEg extends JPanel {
private static final int MAX_ROW_COUNT = 100;
private Random random = new Random();
private JPanel rootPanel = new JPanel();
public PanelsEg() {
rootPanel.setLayout(new BoxLayout(rootPanel, BoxLayout.PAGE_AXIS));
JScrollPane scrollPane = new JScrollPane(rootPanel);
scrollPane.setPreferredSize(new Dimension(400, 400)); // sorry kleopatra
add(scrollPane);
add(new JButton(new AbstractAction("Foo") {
#Override
public void actionPerformed(ActionEvent arg0) {
foo();
}
}));
}
public void foo() {
rootPanel.removeAll();
// rootPanel.setLayout(new BoxLayout(rootPanel, BoxLayout.PAGE_AXIS)); // only need to set layout once
int rowCount = random.nextInt(MAX_ROW_COUNT);
for (int tempRow = 0; tempRow < rowCount ; tempRow++) {
int fileIdTemp = tempRow;
String data = "Data " + (tempRow + 1);
MosaicPanel tempPanel =
new MosaicPanel(fileIdTemp, data);
rootPanel.add(tempPanel);
}
rootPanel.revalidate();
rootPanel.repaint(); // don't forget to repaint if removing
}
private class MosaicPanel extends JPanel {
public MosaicPanel(int fileIdTemp, String data) {
add(new JLabel(data));
}
}
private static void createAndShowGui() {
PanelsEg mainPanel = new PanelsEg();
JFrame frame = new JFrame("PanelsEg");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
This SSCCE works, in that it easily shows removing and adding JPanels to another JPanel that is held by a JScrollPane. If you're still having a problem, you should modify this SSCCE so that it shows your problem.

GridBagLayout Don't make components "jump" after add

I want to use GridBagLayout for a layout that has <= 3 columns, and a variable amount of rows(If anyone knows another layout that can do this easily, please tell me), everytime I press the "add" button a square will be added at the first location that is available. Like so:
|x x x|
|x x x|
|x o |
The x's are squares, and when I press add a new square should be added where the o is now.
I managed to "kind of make it work" like so:
public void addSquare(Square square) {
c.fill = GridBagConstraints.NONE;
c.gridx = nrOfSquares % 3;
c.gridy = (int) (nrOfSquares / 3);
c.weighty = 1;
c.weightx = 1;
c.anchor = GridBagConstraints.NORTHWEST;
c.insets = new Insets(5, 5, 5, 5);
this.container.add(square, c);
this.container.revalidate();
++nrOfSquares;
}
the problem is that the second square I add is added like this:
|x x |
please note that there is an extra space between the first square and the second one. I have the same problem when an extra row is added.
Now how do I fix my code so that the squares don't "jump" and are added like in the first example I gave?
EDIT: as requested, a better example after I converted it to a regular GridLayout:
public class Square extends JPanel {
public Square() {
super();
Dimension SIZE = new Dimension(200, 200);
this.setSize(SIZE);
this.setPreferredSize(SIZE);
this.setMinimumSize(SIZE);
this.setMaximumSize(SIZE);
this.setBackground(Color.ORANGE);
this.setVisible(true);
}
}
public class SquareContainer extends JPanel {
protected JPanel realContainer;
public SquareContainer(int width, int height) {
super();
this.setLayout(new BorderLayout());
this.setBackground(Color.WHITE);
this.setSize(width, height);
this.realContainer = new JPanel();
GridLayout layout = new GridLayout(0, 3);
layout.setHgap(10);
layout.setVgap(10);
this.realContainer.setLayout(layout);
this.realContainer.setBackground(this.getBackground());
JScrollPane scroller = new JScrollPane(this.realContainer);
scroller.getVerticalScrollBar().setUnitIncrement(20);
this.add(scroller, BorderLayout.CENTER);
}
public void addSquare(Square square) {
this.realContainer.add(square);
this.realContainer.revalidate();
}
}
And I just add that to a JFrame:
public class TheGreatFrame extends JFrame {
public TheGreatFrame() {
super();
this.setSize(800, 800);
this.setLocationRelativeTo(null);
this.setLayout(new BorderLayout());
this.setResizable(false);
this.add(new SquareContainer(750, 660), BorderLayout.CENTER);
this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
this.setVisible(true);
}
}

A small example program of using GridLayout:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class GridLayoutEg {
private static void createAndShowGui() {
final JPanel centerPanel = new JPanel(new GridLayout(0, 3));
JButton addBtn = new JButton(new AbstractAction("Add Button") {
#Override
public void actionPerformed(ActionEvent e) {
centerPanel.add(new JButton("X"));
centerPanel.revalidate();
centerPanel.repaint();
SwingUtilities.getWindowAncestor(centerPanel).pack();
}
});
JPanel btnPanel = new JPanel();
btnPanel.add(addBtn);
JPanel mainPanel = new JPanel(new BorderLayout());
mainPanel.add(centerPanel, BorderLayout.CENTER);
mainPanel.add(btnPanel, BorderLayout.PAGE_END);
JFrame frame = new JFrame("GridLayoutEg");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

if all JComponents could have the same HEIGHT and WEIGHT, then look for GridLayout
in case that the JComponent couldn't same WEIGHT, then put each "line" to the separate JPanel (by using BorderLayout or BoxLayout) and use GridLayout for put these JPanels into Container

JScrollPane adding JPanels at the top and keeping current scroll view

I have a JScrollPane that contains a vertical Box. I'm inserting new JPanel's at the top of Box. If I use the scrollbar to scroll down I'd like for the current view to remain where I scrolled down to. For example, if I have 50 panels in the box and use the scrollbar to view panel 20, I'd like the view to remain on box 20 even though other boxes are added on top. Additionally, if I use the scrollbar to scroll back up to the top I'd like the view to display new panels as they are added. Any idea how to do this?
BTW, it isn't necessary to use a JScrollPane or a Box. The example code is just to help explain what I am trying to do.
Example code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TestScrollPane extends JFrame {
JScrollPane scrollPane;
Box box;
private static int panelCount = 0;
public TestScrollPane() {
setPreferredSize(new Dimension(200, 400));
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
scrollPane = new JScrollPane();
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.getVerticalScrollBar().setUnitIncrement(15);
box = Box.createVerticalBox();
scrollPane.getViewport().add(box);
this.add(scrollPane);
this.pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
Timer t = new Timer(500, new ActionListener() {
public void actionPerformed(ActionEvent ae) {
box.add(new TestPanel(), 0);
scrollPane.validate();
}
});
t.setRepeats(true);
t.start();
}
public class TestPanel extends JPanel {
int myId = panelCount++;
public TestPanel() {
this.setLayout(new GridBagLayout());
this.setBorder(BorderFactory.createBevelBorder(1));
JLabel label = new JLabel("" + myId);
label.setHorizontalAlignment(JLabel.CENTER);
label.setVerticalAlignment(JLabel.CENTER);
this.setMaximumSize(new Dimension(100, 100));
this.setPreferredSize(new Dimension(100, 100));
this.add(label);
}
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
TestScrollPane testScrollPane = new TestScrollPane();
}
});
}
}
EDIT:
This is how I ended up changing the code. I feel somewhat foolish for not seeing the obvious. Anyways, thanx to those that helped.
public void actionPerformed(ActionEvent ae) {
Point view = scrollPane.getViewport().getViewPosition();
TestPanel panel = new TestPanel();
box.add(panel, 0);
scrollPane.validate();
if (view.y != 0) {
view.y += panel.getHeight();
scrollPane.getViewport().setViewPosition(view);
}
}
BTW, I had cross posted this question to http://www.coderanch.com/t/528829/GUI/java/JScrollPane-adding-JPanels-at-top#2398276 Just FYI for those that might care.

You could get the bounds of the component you want to make visible (using JComponent's getBounds method), and use that as an input to JViewPort's scrollRectToVisible method.

Something like:
Timer t = new Timer(1000, new ActionListener() {
public void actionPerformed(ActionEvent ae) {
TestPanel panel = new TestPanel();
box.add(panel, 0);
JViewport vp = scrollPane.getViewport();
Point p = vp.getViewPosition();
p.y += panel.getPreferredSize().height;
scrollPane.revalidate();
vp.setViewPosition(p);
}
});