I'm trying to create a Panel which contains N rows and 2 columns, where the first column is a label with a variable length but within certain limits (it varies length according to Language), while the second column contains fields with possibly very long text.
I've tried with GridBagLayout using NetBeans however the results are messy when scaling the panel or adding very long fields..
below a screenshot of the JPanel to see what I mean:
I'd like the left column to be spaced from the left border, the first column to never resize to a smaller value than it's longest label (labels must always be readable), while the second column should visualize up to its available horizontal space and then show dots (and not crop the text).
What's also boring is that although I defined NorthWest for orientation the Panel shows vertically aligned in the center
EDIT: I have used TableColumnAdjuster to use table rows instead of labels for my values so that I can select the values with the mouse.
I still have the rows however fit the length of the text and not of the containing Panel:
public class TestPanel extends JPanel
{
private static ArrayList<String> columnNames = new ArrayList<>();
static JTable table;
MyTableModel myTableModel = new MyTableModel();
static class MyTableModel extends AbstractTableModel
{
private String[] columnNames =
{
"Name", "Value"
};
private Object[][] data =
{
{ "Subject", "very very very very very very very very very very very very very very very very long subject"},
{ "Date", "" },
{ "Location", "" },
{ "Status", "" },
{ "Notes", "" }
};
#Override
public int getColumnCount()
{ return columnNames.length; }
#Override
public int getRowCount()
{ return data.length; }
#Override
public String getColumnName(int col)
{ return columnNames[col]; }
#Override
public Object getValueAt(int row, int col)
{ return data[row][col]; }
#Override
public Class getColumnClass(int c)
{ return getValueAt(0, c).getClass(); }
#Override
public boolean isCellEditable(int row, int col)
{ return false; }
#Override
public void setValueAt(Object value, int row, int col)
{ }
}
public TestPanel()
{
table = new JTable(myTableModel);
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
TableColumnAdjuster tca = new TableColumnAdjuster(table);
tca.adjustColumns();
JPanel panel = new JPanel(new GridBagLayout());
panel.add(table);
GridBagConstraints constraints = new GridBagConstraints();
constraints.weighty = 1.0;
constraints.fill = GridBagConstraints.VERTICAL;
panel.add(Box.createGlue(), constraints);
add(panel);
}
public static void main(String args[])
{
JFrame frame = new JFrame();
frame.setContentPane(new TestPanel());
frame.setSize(300, 800);
frame.setVisible(true);
}
}
while TableColumnAdjuster is from TableColumnAdjuster.. what I get is still as below
You probably have an incorrect usage of the GridBagLayout.
To push all the content to the top, either wrap the GridBagLayout panel into another panel (like a BorderLayout panel in the NORTH position) or add a component at the bottom which takes all the extra space
For all components in the first column, set weightx to 0 while on the second one, set it to something bigger than 0.
To add some space between the left border and the labels, simply use insets
Here is an example illustrating this:
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.util.Random;
import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Gridbag {
public void initUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new GridBagLayout());
Random random = new Random();
for (int i = 0; i < 10; i++) {
String label = "Label " + (i + 1);
StringBuilder fieldValue = new StringBuilder();
int r = 1 + random.nextInt(4);
for (int j = 0; j < r; j++) {
fieldValue.append("Some long value that may be very long in some cases");
}
addField(panel, label, fieldValue.toString());
}
GridBagConstraints constraints = new GridBagConstraints();
constraints.weighty = 1.0;
constraints.fill = GridBagConstraints.VERTICAL;
panel.add(Box.createGlue(), constraints);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
private void addField(JPanel panel, String label, String fieldValue) {
GridBagConstraints labelGBC = new GridBagConstraints();
labelGBC.insets = new Insets(0, 5, 0, 5);
labelGBC.anchor = GridBagConstraints.EAST;
GridBagConstraints fieldGBC = new GridBagConstraints();
fieldGBC.gridwidth = GridBagConstraints.REMAINDER;
fieldGBC.weightx = 1.0;
fieldGBC.anchor = GridBagConstraints.WEST;
panel.add(new JLabel(label), labelGBC);
panel.add(new JLabel(fieldValue), fieldGBC);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Gridbag().initUI();
}
});
}
}
One way to achieve it is to use 3 panels in a 'nested layout'. The panels would be laid out as follows.
Uses BorderLayout for the outer panel, it contains panels 2 & 3.
Uses a single column GridLayout - put in BorderLayout.LINE_START
Uses a single column GridLayout - put in BorderLayout.CENTER
You could use a JTable with two columns and a TableColumnAdjuster or a TableCellRenderer in order to adjust the width of the columns to the longest content.
Related
I have a super basic JTable, which I'm adding to a JFrame, but for some reason frame.pack() doesn't work. I'm setting the row height to the column width so that the cells of the table are squares, but this doesn't seem to work when the window is resized. So, how can I make it so that the cells of the table are always squares, even when resized, and the frame is properly packed? Here's the code for the window:
package me.an.ar.window;
import java.awt.Container;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
public class DayPlanner
{
private JFrame frame;
private void createAndShowGUI()
{
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container container = frame.getContentPane();
Object[][] data = new Object[5][7];
String[] columnNames = { "Day1", "Day2", "Day3", "Day4", "Day5", "Day6", "Day7" };
JTable table = new JTable(data, columnNames);
for (int col = 0; col < table.getColumnCount(); col++)
{
for (int row = 0; row < table.getRowCount(); row++)
{
int colWidth = table.getColumnModel().getColumn(col).getWidth();
table.setRowHeight(row, colWidth);
}
}
container.add(new JScrollPane(table));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private void show()
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
public DayPlanner()
{
show();
}
public static void main(String[] args)
{
new DayPlanner();
}
}
You did not set any LayoutManager. The default is not a FlowLayout but at least not null:
The default content pane will have a BorderLayout manager set on it.
(Java 17 API)
This would mean by resizing the window you would more have to fight with the scrollpane's resizing. What happens if you use
container.add(new JScrollPane(table), BorderLayout.CENTER);
That should let the scrollpane grow and shrink with the frame, and the amount of rows/columns inside the table might vary. This might also get impacted by JTable.setAutoResizeMode().
Option 1
You haven't really mentioned how you are about to use this table (what data will be held and how the user is expected to interact with); however, it sounds like a use case for GridLayout (regarding data cells), as well as GridBagLayout (regarding header cells). Example below:
public class DayPlanner {
private JFrame frame;
Dimension cellSize = new Dimension(75, 75);
private void createAndShowGUI() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create header cells
JPanel p1 = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
String[] columnNames = { "Day 1", "Day 2", "Day 3", "Day 4", "Day 5", "Day 6", "Day 7" };
int count = 0;
for (int i = 0; i < columnNames.length; i++) {
JLabel l = new JLabel(columnNames[i], SwingConstants.CENTER);
l.setFont(new Font("Times New Roman", Font.BOLD, 14));
l.setBackground(new Color(238, 238, 238));
l.setOpaque(true);
l.setBorder(BorderFactory.createMatteBorder(0, 0, 0, 1, new Color(122, 138, 153)));
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 5; // adjusts cell's height
c.weightx = 0.5;
c.gridx = count++;
c.gridy = 0;
p1.add(l, c);
}
// Create data cells
JPanel p2 = new JPanel();
p2.setLayout(new GridLayout(5, 7));
for (int i = 0; i < 35; i++) {
JLabel l = new JLabel("<html> This is some sample text " + i + "</html>"); // html tags allow text-wrapping
l.setFont(new Font("Times New Roman", Font.PLAIN, 14));
l.setVerticalAlignment(SwingConstants.TOP);
l.setHorizontalAlignment(SwingConstants.LEFT);
l.setPreferredSize(cellSize);
l.setBackground(Color.WHITE);
l.setOpaque(true);
l.setBorder(BorderFactory.createMatteBorder(0, 0, 1, 1, new Color(122, 138, 153)));
p2.add(l);
}
JScrollPane sp = new JScrollPane(p2);
sp.getVerticalScrollBar().setUnitIncrement((int) cellSize.getHeight() / 2); // adjusts scrolling speed
sp.getViewport().setBackground(Color.WHITE);
Container container = frame.getContentPane();
container.add(p1, BorderLayout.NORTH);
container.add(sp, BorderLayout.CENTER);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new DayPlanner().createAndShowGUI();
}
});
}
}
Option 2
If you still want to use the JTable given in your question, you could add a ComponentListener to your JFrame, so that you can listen to "resize events", allowing you to readjust the cells' size and retain their square shape.
frame.addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent evt) {
for (int row = 0; row < table.getRowCount(); row++) {
int colWidth = table.getColumnModel().getColumn(0).getWidth();
table.setRowHeight(row, colWidth);
}
}
});
As for the pack() issue, you could set the initial size of the JFrame according to the columns and rows in your table (remember to comment out frame.pack();). The below, although it would remove the empty space at the bottom of the frame, it wouldn't, however, stop the user from resizing the window and bringing that back.
int colWidth = table.getColumnModel().getColumn(0).getWidth();
frame.setSize(7 * colWidth, 5 * table.getRowHeight(0) + 25);
//frame.pack();
I am creating something like inspector panel for my program, so I can easily change some variables at runtime.
When you run the code bellow, you should see something like this:
inspector screenshot
There are several things that bothers me and I still cannot make them to work properly.
Items are verticaly aligned to the center... I have tried setting anchor to the North but it remains the same. In the example code bellow, there is one line commented out that can fix this: inspector.finish() but the solution seems kinda hacky to me. It works by adding empty JPanel as last item on the panel, acting as some kind of vertical glue to expand the lower area and push the components up. I don't like this, because with this solution I no longer can add more items to the inspector later at runtime.
If you add more items to the inspector (you can do this by changing n variable that fills the inspector with some test data) the scroll bar will not show up, and all the lower items are out of screen even it's all wrapped inside JScrollPane... I have tried several hacks to fix this but none of them works correctly. One of them was setting preferredSize of JPanel to some hard-coded dimensions but I don't like this because I don't know exact size of the panel.
When you push some of the spinner buttons and then click on the combobox (titled as "choose me"), the options are hidden behind the button bellow. This looks like some kind of z-ordering issue. Maybe this is bug in swing, dunno.
When you resizing the window vertically to smaller size, the items on the top will begin to shrink instead of staying the same size. Is there any option to set them constant height at all times?
Maybe I am using the wrong layout manager, but I don't know which other one to choose. I was thinking about simple grid layout, but this does not allow me to do things like having some rows with one item and others with multiple items in such a way that they will always use the whole width "capacity" of the row.
example code:
import java.awt.*;
import javax.swing.*;
public class Test {
// Setup test scenario
public Test() {
// Create window
JFrame f = new JFrame();
f.setLayout(new BorderLayout());
f.setSize(800, 600);
f.setTitle("Inspector");
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
// Create panel which will be used for the inspector
JPanel p = new JPanel();
p.setPreferredSize(new Dimension(200, 0));
// Encapsulate it to the scroll panel so it can grow vertically
JScrollPane sp = new JScrollPane();
sp.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
sp.setViewportView(p);
// Create the inspector inside panel p
Inspector inspector = new Inspector(p);
// Fill the inspector with some test data
int n = 3;
for (int i = 0; i < n; ++i) {
inspector.addTitle("Title");
inspector.addButton("push me");
inspector.addCheckBox("check me");
inspector.addSpinner("Spin me");
inspector.addTextField("Edit me", "here");
inspector.addComboBox("Choose one", new String[]{"A", "B", "C"});
inspector.addSeparator();
}
//inspector.finish();
// The inspector will be on the right side of the window
f.getContentPane().add(sp, BorderLayout.LINE_END);
// Show the window
f.setVisible(true);
}
// Main method
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new Test();
}
});
}
// Inspector class itself
private class Inspector {
private final JPanel panel;
private final GridBagConstraints constraints;
private int itemsCount = 0;
public Inspector(JPanel p) {
panel = p;
panel.setLayout(new GridBagLayout());
constraints = new GridBagConstraints();
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.weightx = 0.5;
}
// Adds component which will span across whole row
private void addComponent(Component component) {
constraints.gridx = 0;
constraints.gridwidth = 2;
constraints.gridy = itemsCount;
panel.add(component, constraints);
itemsCount++;
}
// Adds descriptive label on the left and component on the right side of the row
private void addNamedComponent(String description, Component component) {
constraints.gridx = 0;
constraints.gridy = itemsCount;
constraints.gridwidth = 1;
panel.add(new JLabel(description), constraints);
constraints.gridx = 1;
constraints.gridy = itemsCount;
constraints.gridwidth = 1;
panel.add(component, constraints);
itemsCount++;
}
public void addSeparator() {
// (little hacky)
addComponent(new JPanel());
}
public void addTitle(String title) {
addComponent(new JLabel(title));
}
public void addButton(String actionName) {
addComponent(new Button(actionName));
}
public void addCheckBox(String description) {
addNamedComponent(description, new JCheckBox());
}
public void addSpinner(String description) {
addNamedComponent(description, new JSpinner());
}
public void addTextField(String description, String text) {
addNamedComponent(description, new JTextField(text));
}
public void addComboBox(String description, String[] options) {
JComboBox<String> comboBox = new JComboBox<>();
ComboBoxModel<String> model = new DefaultComboBoxModel<>(options);
comboBox.setModel(model);
addNamedComponent(description, comboBox);
}
public void finish() {
constraints.gridx = 0;
constraints.gridy = itemsCount;
constraints.gridwidth = 2;
constraints.weighty = 1.0;
panel.add(new JPanel(), constraints);
}
}
}
The Reason that you can't scroll up or down is because you are setting the preferred size of sp to 200x0. You need to remove this line.
p.setPreferredSize(new Dimension(200, 0));
As for the issue with everything being centered instead of at the top. I would prefer to leave p with the default FlowLayout and give each "section" it's own panel, and the make that panel a GridBagLayout. By doing this you probably will not need addSeparator() anymore.
public class Test {
// Setup test scenario
public Test() {
// Create window
JFrame f = new JFrame();
f.setLayout(new BorderLayout());
f.setSize(800, 600);
f.setTitle("Inspector");
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
// Create panel which will be used for the inspector
JPanel p = new JPanel();
// Encapsulate it to the scroll panel so it can grow vertically
JScrollPane sp = new JScrollPane();
sp.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
sp.setViewportView(p);
// Create the inspector inside panel p
Inspector inspector = new Inspector(p);
// Fill the inspector with some test data
int n = 2;
for (int i = 0; i < n; ++i) {
inspector.addTitle("Title");
inspector.addButton("push me");
inspector.addCheckBox("check me");
inspector.addSpinner("Spin me");
inspector.addTextField("Edit me", "here");
inspector.addComboBox("Choose one", new String[]{"A", "B", "C"});
}
// The inspector will be on the right side of the window
f.getContentPane().add(sp, BorderLayout.LINE_END);
// Show the window
f.setVisible(true);
}
// Main method
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new Test();
}
});
}
// Inspector class itself
private class Inspector {
private final JPanel panel;
private final GridBagConstraints constraints;
private int itemsCount = 0;
public Inspector(JPanel p) {
panel = new JPanel();
p.add(panel);
panel.setLayout(new GridBagLayout());
constraints = new GridBagConstraints();
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.weightx = 1.0;
}
// Adds component which will span across whole row
private void addComponent(Component component) {
constraints.gridx = 0;
constraints.gridwidth = 2;
constraints.gridy = itemsCount;
panel.add(component, constraints);
itemsCount++;
}
// Adds descriptive label on the left and component on the right side of the row
private void addNamedComponent(String description, Component component) {
constraints.gridx = 0;
constraints.gridy = itemsCount;
constraints.gridwidth = 1;
panel.add(new JLabel(description), constraints);
constraints.gridx = 1;
constraints.gridy = itemsCount;
constraints.gridwidth = 1;
panel.add(component, constraints);
itemsCount++;
}
public void addSeparator() {
// (little hacky)
addComponent(new JPanel());
}
public void addTitle(String title) {
addComponent(new JLabel(title));
}
public void addButton(String actionName) {
addComponent(new Button(actionName));
}
public void addCheckBox(String description) {
addNamedComponent(description, new JCheckBox());
}
public void addSpinner(String description) {
addNamedComponent(description, new JSpinner());
}
public void addTextField(String description, String text) {
addNamedComponent(description, new JTextField(text));
}
public void addComboBox(String description, String[] options) {
JComboBox<String> comboBox = new JComboBox<>();
ComboBoxModel<String> model = new DefaultComboBoxModel<>(options);
comboBox.setModel(model);
addNamedComponent(description, comboBox);
}
public void finish() {
constraints.gridx = 0;
constraints.gridy = itemsCount;
constraints.gridwidth = 2;
constraints.weighty = 1.0;
panel.add(new JPanel(), constraints);
}
}
}
I've looked everywhere but can't seem to figure this out. I just want to pull out a cell's value from my JTable when a user clicks on it.
However at the moment I am getting -1 so I suppose double clicking results in no row being detected. Here is the code:
import java.awt.*;
import java.awt.event.*;
import java.sql.SQLException;
import javax.swing.*;
import javax.swing.table.TableColumn;
public class CardLayoutExample {
private static JScrollPane scrollPane;
public static void main(String[] arguments) throws SQLException {
// main window
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame window = new JFrame("CardLayout Example");
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setSize(1500,800);
window.getContentPane().setLayout(new BorderLayout());
final CardLayout cardLayout = new CardLayout();
final JPanel cardPanel = new JPanel(cardLayout);
JPanel card3 = new JPanel();
cardPanel.add(card3,"All Patients");
String AllPatients="select * from tblPtDetails";
JTable tablePatientDt = new JTable(Bquery.buildTableModel(Bquery.resultQuery(AllPatients)));
tablePatientDt.setEnabled(false);
tablePatientDt.setPreferredScrollableViewportSize(new Dimension(1200, 400));
tablePatientDt.setAutoResizeMode( JTable.AUTO_RESIZE_OFF );
tablePatientDt.setRowHeight(30);
tablePatientDt.setAutoCreateRowSorter(true);
card3.add(tablePatientDt);
card3.add(new JScrollPane(tablePatientDt), BorderLayout.CENTER);
for (int i = 0; i < (tablePatientDt.getColumnCount()); i++) {
TableColumn columnPatients = null;
columnPatients = tablePatientDt.getColumnModel().getColumn(i);
columnPatients.setPreferredWidth(70); //sport column is bigger
}
tablePatientDt.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) {
int row = tablePatientDt.getSelectedRow();
int column = tablePatientDt.getSelectedColumn();
//Object val= tablePatientDt.getModel().getValueAt(row, column);
//tablePatientDt.getModel().getValueAt(row, column);
//return tablePatientDt.getModel().getValueAt(row, column);
System.out.println(row);
JFrame newFrame = new JFrame();
newFrame.setTitle("Detail Screen");
newFrame.setVisible(true);
}
}
});
Your main problem is here:
tablePatientDt.setEnabled(false);
Because the table is not enabled, no cell or row can ever be selected, and so the selected row will always be -1. Solution: get rid of that line. Instead, if you don't want a cell to be editable on double click, override the JTable or its model and override the isCellEditable method:
e.g.,
// create your JTable model here:
DefaultTableModel model = ......
JTable tablePatientDt = new JTable(model){
#Override
public boolean isCellEditable(int row, int column) {
return false;
}
Other issues: don't add the JTable to more than one component as you're doing. That spells great risk for trouble since Swing components can be added to only one component at a time.
A side recommendation: in your future questions post only small compilable and runnable programs. Your code above cannot run since it has database dependencies that we don't have access to, and is also incomplete. In order to find your problem, I had to take your code and create a small runnable program with it, an mcve (please read the link):
import java.awt.*;
import java.awt.event.*;
import java.sql.SQLException;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;
public class CardLayoutExample {
private static JScrollPane scrollPane;
public static void main(String[] arguments) throws SQLException {
// main window
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame window = new JFrame("CardLayout Example");
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// !! window.setSize(1500, 800);
window.getContentPane().setLayout(new BorderLayout());
final CardLayout cardLayout = new CardLayout();
final JPanel cardPanel = new JPanel(cardLayout);
JPanel card3 = new JPanel();
cardPanel.add(card3, "All Patients");
String AllPatients = "select * from tblPtDetails";
//!!
String[][] data = {{"1", "2", "3"}, {"4", "5", "6"}, {"7", "8", "9"}};
String[] columnNames = {"One", "Two", "Three"};
DefaultTableModel model = new DefaultTableModel(data, columnNames);
// !! JTable tablePatientDt = new JTable(Bquery.buildTableModel(Bquery.resultQuery(AllPatients)));
JTable tablePatientDt = new JTable(model){
#Override
public boolean isCellEditable(int row, int column) {
return false;
}
};
// !! tablePatientDt.setEnabled(false);
tablePatientDt.setPreferredScrollableViewportSize(new Dimension(1200, 400));
tablePatientDt.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
tablePatientDt.setRowHeight(30);
tablePatientDt.setAutoCreateRowSorter(true);
// !! card3.add(tablePatientDt);
card3.add(new JScrollPane(tablePatientDt), BorderLayout.CENTER);
for (int i = 0; i < (tablePatientDt.getColumnCount()); i++) {
TableColumn columnPatients = null;
columnPatients = tablePatientDt.getColumnModel().getColumn(i);
columnPatients.setPreferredWidth(70); // sport column is bigger
}
tablePatientDt.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) {
int row = tablePatientDt.getSelectedRow();
int column = tablePatientDt.getSelectedColumn();
// Object val= tablePatientDt.getModel().getValueAt(row,
// column);
// tablePatientDt.getModel().getValueAt(row, column);
// return tablePatientDt.getModel().getValueAt(row, column);
System.out.println(row);
JFrame newFrame = new JFrame();
newFrame.setTitle("Detail Screen");
newFrame.setVisible(true);
}
}
});
//!!
window.add(cardPanel);
window.pack();
window.setVisible(true);
}
}
But really this effort should be yours not mine, since we're all volunteers, and you're the one asking for volunteer help in solving a problem. So in the future we ask that you create your own mcve to go with your questions.
Also that detail window shouldn't be a JFrame but rather a JDialog.
Say I have two components, A and B, in a JPanel. I want Component A to stay left aligned, while Component B does its best to stay in the middle of the panel. I mocked up the following demo (sorry for the quality, I made it in paint):
What I am doing now is using a GridBagLayout on the JPanel, and keeping A left aligned while keeping B centered, but B stays centered within the 2nd column, so it is centered in the space remaining after A is placed, instead of centered with respect to the panel as a whole.
I cannot use any 3rd party libraries for this. Is there a way to do this using pure Swing?
Edit:
Firefly's answer is correct (as marked) but I created an SSCCE showing my original problem (first row), Hovercraft Full Of Eels' attempted solution (second row), and the Firefly's correct solution (third row). I figured it can't hurt to post it:
package stackoverflow;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.LayoutManager2;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class StackOverflowTest extends JFrame
{
public StackOverflowTest()
{
super("Stack Overflow Test");
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
JPanel testPanel = new JPanel(new GridLayout(3, 1));
// set up grid bag layout example
JPanel gridBagPanel = new JPanel(new GridBagLayout());
GridBagConstraints gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 0;
gridBagConstraints.anchor = GridBagConstraints.LINE_START;
gridBagPanel.add(getA(), gridBagConstraints);
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 1;
gridBagConstraints.gridy = 0;
gridBagConstraints.anchor = GridBagConstraints.CENTER;
gridBagConstraints.weightx = 1.0;
gridBagPanel.add(getB(), gridBagConstraints);
testPanel.add(gridBagPanel);
// set up border layout panel
JPanel borderPanel = new JPanel(new BorderLayout());
borderPanel.add(getA(), BorderLayout.LINE_START);
JPanel flowPanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 0, 0));
borderPanel.add(flowPanel, BorderLayout.CENTER);
flowPanel.add(getB());
testPanel.add(borderPanel);
// set up sly493 layout panel
JPanel sly493LayoutPanel = new JPanel(new Sly493LayoutManager());
sly493LayoutPanel.add(getA(), Sly493LayoutManager.LEFT);
sly493LayoutPanel.add(getB(), Sly493LayoutManager.CENTERED);
testPanel.add(sly493LayoutPanel);
// set up panel to act as the midpoint marker
JPanel midpointMarkerPanel = new JPanel()
{
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.BLACK);
int w = getWidth();
int h = getHeight();
int x = w / 2;
g2.drawLine(x, 0, x, h);
g2.drawLine(x, 0, x - (h / 5), (h / 5));
g2.drawLine(x, 0, x + (h / 5), (h / 5));
}
};
midpointMarkerPanel.setPreferredSize(new Dimension(1, 50));
// setup up content pane
JPanel contentPane = new JPanel(new BorderLayout());
contentPane.add(testPanel, BorderLayout.NORTH);
contentPane.add(midpointMarkerPanel, BorderLayout.CENTER);
this.setContentPane(contentPane);
pack();
}
private JPanel getA()
{
JPanel aPanel = new JPanel(new BorderLayout());
JLabel aLabel = new JLabel("A", JLabel.CENTER);
aLabel.setFont(aLabel.getFont().deriveFont(Font.BOLD, 36));
aPanel.add(aLabel, BorderLayout.CENTER);
aPanel.setBackground(Color.RED);
aPanel.setPreferredSize(new Dimension(50, 50));
return aPanel;
}
private JPanel getB()
{
JPanel bPanel = new JPanel();
JLabel bLabel = new JLabel("B", JLabel.CENTER);
bLabel.setForeground(Color.WHITE);
bLabel.setFont(bLabel.getFont().deriveFont(Font.BOLD, 36));
bPanel.add(bLabel, BorderLayout.CENTER);
bPanel.setBackground(Color.BLUE);
bPanel.setPreferredSize(new Dimension(50, 50));
return bPanel;
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
new StackOverflowTest().setVisible(true);
}
});
}
private static class Sly493LayoutManager implements LayoutManager2
{
public static final Integer LEFT = 0;
public static final Integer CENTERED = 1;
private Component leftComponent;
private Component centeredComponent;
#Override
public void addLayoutComponent(String name, Component comp)
{
}
#Override
public void removeLayoutComponent(Component comp)
{
if (leftComponent == comp)
{
leftComponent = null;
}
else if (centeredComponent == comp)
{
centeredComponent = null;
}
}
#Override
public Dimension preferredLayoutSize(Container parent)
{
Dimension d = new Dimension();
for (Component c : parent.getComponents())
{
//wide enough to stack the left and center components horizontally without overlap
d.width += c.getPreferredSize().width;
//tall enough to fit the tallest component
d.height = Math.max(d.height, c.getPreferredSize().height);
}
return d;
}
#Override
public Dimension minimumLayoutSize(Container parent)
{
return preferredLayoutSize(parent);
}
#Override
public void layoutContainer(Container parent)
{
//in this method we will:
//1) position the left component on the left edge of the parent and center it vertically
//2) position the center component in the center of the parent (as long as it would not overlap
//the left component) and center it vertically
int leftComponentWidth = leftComponent.getPreferredSize().width;
int leftComponentHeight = leftComponent.getPreferredSize().height;
int centeredComponentWidth = centeredComponent.getPreferredSize().width;
int centeredComponentHeight = centeredComponent.getPreferredSize().height;
leftComponent.setBounds(0, (parent.getHeight() - leftComponentHeight) / 2, leftComponentWidth, leftComponentHeight);
int leftComponentRightEdge = leftComponent.getX() + leftComponent.getWidth();
int centerComponentLeftEdge = (parent.getWidth() - centeredComponentWidth) / 2;
int centerComponentTopEdge = (parent.getHeight() - centeredComponentHeight) / 2;
if (leftComponentRightEdge >= centerComponentLeftEdge)
{
//Center component will "do its best" to remain in the center
//but it will not do so if it would cause it to overlap the left component
centerComponentLeftEdge = leftComponentRightEdge;
}
centeredComponent.setBounds(centerComponentLeftEdge,
centerComponentTopEdge,
centeredComponentWidth,
centeredComponentHeight);
}
#Override
public void addLayoutComponent(Component comp, Object constraints)
{
if (LEFT.equals(constraints))
{
if (leftComponent != null)
{
throw new IllegalStateException("A left component has already been assigned to this layout.");
}
leftComponent = comp;
}
else if (CENTERED.equals(constraints))
{
if (centeredComponent != null)
{
throw new IllegalStateException("A centered component has already been assigned to this layout.");
}
centeredComponent = comp;
}
else
{
throw new IllegalStateException("Unexpected constraints '" + constraints + "'.");
}
}
#Override
public Dimension maximumLayoutSize(Container target)
{
return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
}
#Override
public float getLayoutAlignmentX(Container target)
{
return 0;
}
#Override
public float getLayoutAlignmentY(Container target)
{
return 0;
}
#Override
public void invalidateLayout(Container target)
{
}
}
}
If I'm understanding your needs correctly, you want B centered relative to the parent as a whole, not centered in the space left over after A is positioned. That makes this problem interesting and after testing the other suggested answers, I don't believe they can meet that requirement.
I'm having trouble thinking of a way to combine the built-in layout managers in a way that would achieve that. So, I've hacked up a custom implementation of LayoutManager2.
The following executable example may meet your needs. The implementation is quick and dirty and is in no way an example of a good generalized layout manager, but it appears to meet your requirements and behaves like your drawings made me think it should. I interpreted your requirement that "B does its best to stay in the middle of the panel" to mean that B should try to remain centered relative to the panel as a whole, but not at the expense of overlapping A.
package com.example;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.LayoutManager2;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Example {
public Example() {
JPanel a = new JPanel();
a.setBackground(Color.RED);
a.setPreferredSize(new Dimension(128, 128));
JPanel b = new JPanel();
b.setBackground(Color.BLUE);
b.setPreferredSize(new Dimension(128, 128));
JPanel panel = new JPanel(new Sly493LayoutManager());
panel.add(a, Sly493LayoutManager.LEFT);
panel.add(b, Sly493LayoutManager.CENTERED);
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
new Example();
}
private static class Sly493LayoutManager implements LayoutManager2 {
public static final Integer LEFT = 0;
public static final Integer CENTERED = 1;
private Component leftComponent;
private Component centeredComponent;
#Override
public void addLayoutComponent(String name, Component comp) { }
#Override
public void removeLayoutComponent(Component comp) {
if (leftComponent == comp) {
leftComponent = null;
} else if (centeredComponent == comp) {
centeredComponent = null;
}
}
#Override
public Dimension preferredLayoutSize(Container parent) {
Dimension d = new Dimension();
for (Component c : parent.getComponents()) {
//wide enough to stack the left and center components horizontally without overlap
d.width += c.getPreferredSize().width;
//tall enough to fit the tallest component
d.height = Math.max(d.height, c.getPreferredSize().height);
}
return d;
}
#Override
public Dimension minimumLayoutSize(Container parent) {
return preferredLayoutSize(parent);
}
#Override
public void layoutContainer(Container parent) {
//in this method we will:
//1) position the left component on the left edge of the parent and center it vertically
//2) position the center component in the center of the parent (as long as it would not overlap
//the left component) and center it vertically
int leftComponentWidth = leftComponent.getPreferredSize().width;
int leftComponentHeight = leftComponent.getPreferredSize().height;
int centeredComponentWidth = centeredComponent.getPreferredSize().width;
int centeredComponentHeight = centeredComponent.getPreferredSize().height;
leftComponent.setBounds(0, (parent.getHeight() - leftComponentHeight) / 2, leftComponentWidth, leftComponentHeight);
int leftComponentRightEdge = leftComponent.getX() + leftComponent.getWidth();
int centerComponentLeftEdge = (parent.getWidth() - centeredComponentWidth) / 2;
int centerComponentTopEdge = (parent.getHeight() - centeredComponentHeight) / 2;
if (leftComponentRightEdge >= centerComponentLeftEdge) {
//Center component will "do its best" to remain in the center
//but it will not do so if it would cause it to overlap the left component
centerComponentLeftEdge = leftComponentRightEdge;
}
centeredComponent.setBounds(centerComponentLeftEdge,
centerComponentTopEdge,
centeredComponentWidth,
centeredComponentHeight);
}
#Override
public void addLayoutComponent(Component comp, Object constraints) {
if (LEFT.equals(constraints)) {
if (leftComponent != null) {
throw new IllegalStateException("A left component has already been assigned to this layout.");
}
leftComponent = comp;
} else if (CENTERED.equals(constraints)) {
if (centeredComponent != null) {
throw new IllegalStateException("A centered component has already been assigned to this layout.");
}
centeredComponent = comp;
} else {
throw new IllegalStateException("Unexpected constraints '" + constraints + "'.");
}
}
#Override
public Dimension maximumLayoutSize(Container target) {
return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
}
#Override
public float getLayoutAlignmentX(Container target) {
return 0;
}
#Override
public float getLayoutAlignmentY(Container target) {
return 0;
}
#Override
public void invalidateLayout(Container target) {
}
}
}
Here's a really quick and dirty way, similar to Firefly's answer - just create a JPanel with null Layout, and place the two child panels in its paintComponent method:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Example extends JPanel {
protected JPanel a;
protected JPanel b;
int size = 200;
public Example() {
setLayout( null );
a = new JPanel();
a.setBackground( Color.red );
a.setPreferredSize( new Dimension( size, size ) );
b = new JPanel();
b.setBackground( Color.blue );
b.setPreferredSize( new Dimension( size, size ) );
add( a );
add( b );
setPreferredSize( new Dimension( 4 * size, size ) );
}
#Override
public void paintComponent( final Graphics g ) {
super.paintComponent( g );
a.setBounds( 0, 0, size, size );
int w = getWidth();
int x = (w - size) / 2;
if ( x < size ) {
x = size;
}
b.setBounds( x, 0, size, size );
}
public static void main( String[] args ) {
SwingUtilities.invokeLater( new Runnable() {
#Override
public void run() {
// Create and set up the window.
JFrame jf = new JFrame();
jf.setName( "Example" );
Example item = new Example();
jf.add( item );
// Display the window.
jf.pack();
jf.setVisible( true );
jf.addWindowListener( new WindowAdapter() {
#Override
public void windowClosing( WindowEvent arg0 ) {
System.exit( 0 );
}
} );
}
} );
}
}
Have the overall container use BorderLayout
Add A to its BorderLayout.LINE_START position.
Add another FlowLayout JPanel BorderLayout.CENTER. This panel will hold B.
Add B to the JPanel above. Since FlowLayout defaults to FlowLayout.CENTER, B should be centered in this JPanel.
For my practical purposes, I did not need precise centering. And I needed right alignment. And I needed two rows. And the text on the right was much shorter than the text in the center. So the trick is:
have both rows in a separate JPanel
use GridBagLayout
the "centered" item is really the left item, but it is right-aligned.
Some code from a real app (the {} blocks used to be in different functions, but that's not important now):
JPanel myPanel = new JPanel(new GridBagLayout());
JLabel centerFirst = new JLabel("first line");
JLabel rightFirst = new JLabel("...");
{
GridBagConstraints gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 1;
gridBagConstraints.gridy = 0;
gridBagConstraints.anchor = GridBagConstraints.EAST;
gridBagConstraints.weightx = 0.5;
myPanel.add(centerFirst, gridBagConstraints);
}
{
GridBagConstraints gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 3;
gridBagConstraints.gridy = 0;
gridBagConstraints.anchor = GridBagConstraints.EAST;
gridBagConstraints.weightx = 0.5; // you don't really need 0.5 and 0.5, it may be 0.1 and 0.1, two equal values
myPanel.add(rightFirst, gridBagConstraints);
}
JLabel centerSecond = new JLabel("second line");
JLabel rightSecond = new JLabel("...");
{
GridBagConstraints gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 1;
gridBagConstraints.gridy = 1;
gridBagConstraints.anchor = GridBagConstraints.EAST;
gridBagConstraints.weightx = 0.5;
myPanel.add(centerSecond, gridBagConstraints);
}
{
GridBagConstraints gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 3;
gridBagConstraints.gridy = 1;
gridBagConstraints.anchor = GridBagConstraints.EAST;
gridBagConstraints.weightx = 0.5;
myPanel.add(rightSecond, gridBagConstraints);
}
//...
// the main frame uses GridBagLayout too
JFrame frame = new JFrame();
{
GridBagLayout gbl = new GridBagLayout();
//...
frame.setLayout(gbl);
}
// myPanel: full width of the enclosing GridBagLayout
{
GridBagLayout gbl = (GridBagLayout) frame.getContentPane().getLayout();
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0; // it will occupy columns 0 and 1 of the GridBagLayout
gbc.gridy = 4; // and there will be stuff above it
gbc.gridheight = 1; // full width, therefore height=1 is enough
gbc.gridwidth = 2; // the number of columns in this GridBagLayout
gbc.fill = GridBagConstraints.HORIZONTAL;
gbl.setConstraints(myPanel, gbc);
frame.add(myPanel);
}
Box layout
container.add(componentA)
container.add(Box.createHorisontalGlue())
container.add(componentB)
container.add(Box.createHorisontalGlue())
I am trying to make a JFrame for displaying the data that my beta-testers are to send me (this part I have already done), and a JTabbedPane for the charts (for their use). //I am hoping for something that, ignoring stuff like the look-and-feel (and coloring; I was too lazy to color the picture all the way), would look something like this:
. //I would have to use CardLayout for the JComboBox to display a different table and a different JTabbedPane for the newly-selected mode; that means two tables and two JTabbedPanes.
I have tried to make a small (extremely-simplified!) example of this setup, a JFrame with only a (very simple!) JTabbedPane and a small JTable. The example works if I give my JPanel (that houses both components) a BorderLayout, but as soon as I give it a GridLayout (or a GridBagLayout //the very Layout I will end up using), only the last component displays no matter what I try! Why is this?
If it would help any (it might, given how much of a newbie I am to this), here is the example code:
JPanelLayoutTest.java
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.HeadlessException;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
public class JPanelLayoutTest extends JFrame {
private JPanel aPanel;
private JTabbedPane tabbedPane;
private JTable someTable;
public JPanelLayoutTest(String title) throws HeadlessException {
super(title);
aPanel = setupPanel();
}
private JPanel setupPanel()
{
GridBagLayout gridBag = new GridBagLayout();
GridBagConstraints constraints = new GridBagConstraints();
//making the panel have two columns and one row
JPanel panel = new JPanel(gridBag);
//add someTable to top
someTable = new JTable(new SampleTableModel());
/*JPanel somePanel = new JPanel();
somePanel.add(new JScrollPane(someTable));*/
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridheight = 1;
constraints.gridwidth = 1;
gridBag.setConstraints(new JScrollPane(someTable), constraints);
add(new JScrollPane(someTable));
//add tabbedPane to bottom
tabbedPane = new JTabbedPane();
tabbedPane.addTab("some component", new JLabel("some text"));
/*JPanel someOtherPanel = new JPanel();
someOtherPanel.add(tabbedPane);*/
constraints.gridy = 1;
gridBag.setConstraints(tabbedPane, constraints);
add(tabbedPane);
//add(tabbedPane);
return panel;
}
public void turnOnWindow()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
//setSize(400,200);
pack();
}
public static void main(String[] args) {
JPanelLayoutTest frame = new JPanelLayoutTest("JPanel Layout Test");
frame.turnOnWindow();
}
}
//Pardon the indentation; I wish this forum had support for the [code][/code] tag
SampleTableModel.java
import javax.swing.table.AbstractTableModel;
public class SampleTableModel extends AbstractTableModel {
//declaring the static arrays that will be the data for the table
private final String[] columnNames = {"Account", "Full Name", "Balance"};
private final int[] acctNumbers = {1000443749, 190238420, 928355};
private final String[] fullNames = {"Mike Warren", "Jack Smith", "Sarah Brown"};
private final double[] acctBalances = {193.38, 289.28, 21034.29};
public SampleTableModel()
{
// I do nothing in here; there is no reason to.
}
#Override
public int getColumnCount() { return columnNames.length; }
#Override
public int getRowCount() { return acctNumbers.length; }
#Override
public Object getValueAt(int row, int column) {
switch (column)
{
case 0:
return new Integer(acctNumbers[row]);
case 1:
return fullNames[row];
case 2:
return new Double(acctBalances[row]);
default:
return null; //there should be no way the code would ever reach here
}
}
#Override
public String getColumnName(int index) { return columnNames[index]; }
//Again, forgive my horrible indentation near the end here...
}
Instead of:
private JPanel setupPanel()
{
GridBagLayout gridBag = new GridBagLayout();
GridBagConstraints constraints = new GridBagConstraints();
//making the panel have two columns and one row
JPanel panel = new JPanel(gridBag);
//add someTable to top
someTable = new JTable(new SampleTableModel());
/*JPanel somePanel = new JPanel();
somePanel.add(new JScrollPane(someTable));*/
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridheight = 1;
constraints.gridwidth = 1;
gridBag.setConstraints(new JScrollPane(someTable), constraints);
add(new JScrollPane(someTable));
//add tabbedPane to bottom
tabbedPane = new JTabbedPane();
tabbedPane.addTab("some component", new JLabel("some text"));
/*JPanel someOtherPanel = new JPanel();
someOtherPanel.add(tabbedPane);*/
constraints.gridy = 1;
gridBag.setConstraints(tabbedPane, constraints);
add(tabbedPane);
//add(tabbedPane);
return panel;
}
I think you will have better luck building your panel as an extention to the JPanel:
EDIT: Forgot to mention that this code is very reusable and allows to to pass in other objects into the JPanel...save you a ton of work as it allows you to overload constructors for different scenarios.
//You can call new objects such as:
new MyPanel(data, otherComponent);
public class MyPanel extends JPanel{
String data;
public MyPanel(String someData, SomeOtherClass aClass){
this.data = someData;
setLayout(new GridBagLayout());
GridBagConstraints constraints = new GridBagConstraints();
JPanel panel = new JPanel(gridBag);
//New addition
constraints.gridx = 0;
constraints.gridy = 0;
//add components to the JPanel with your grid (constraints)
add(new JScrollPane(someTable), constraints)
//New addition
constraints.gridx = 0;
constraints.gridy = 1;
//add components to the JPanel with your grid (constraints)
add(tabbedPane , constraints);
}
public String getData(){
return this.data;
}
}
This follows the MVC pattern (which i recommend looking into if you plan on designing more swing). I know it really helped me!
Your Problem
When using a GridBagLayout (and many other layouts), you need to pass the constraints you wish to use for a particular component, otherwise the layout manager will use its default values.
For example, you are doing...
gridBag.setConstraints(new JScrollPane(someTable), constraints);
add(new JScrollPane(someTable));
But the component you are adding is not the component your applied the constraints to. Instead, do something more like...
add(new JScrollPane(someTable), constraints);
A (possible) better solution
Break your UI down into sections. Each section has its own unique requirements (I see three sections).
I see a GridLayout as the base layout, onto which you want to add three additional panels, which represent three sections of your UI.
This commonly known as compound layouts as you building a series of layouts to produce your final result