Develop Reference

Change the font color in a specific cell of a JTable?

Before starting, I've viewed a handful of solutions as well as documentation. I can't seem to figure out why my code isn't working the way I believe it should work. I've extended DefaultTableCellRenderer but I don't believe it is being applied - that or I messed things up somewhere.
Here are the threads / websites I've looked into before posting this question:
Swing - Is it possible to set the font color of 'specific' text within a JTable cell?
JTable Cell Renderer
http://docs.oracle.com/javase/tutorial/uiswing/components/table.html
I realize the first link uses HTML to change the font color, but I would think the way I went about it should produce the same result.
To make it easier on those who want to help me figure out the issues, I've created an SSCCE.
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
public class TableTest {
private static final int IMPORTANT_COLUMN = 2;
public static void createAndShowGUI() {
Object[][] data = new Object[2][4];
//create sample data
String[] realRowData = { "1", "One", "1.0.2", "compile" };
String[] fakeRowData = { "2", "Two", "1.3.2-FAKE", "compile" };
//populate sample data
for(int i = 0; i < realRowData.length; i++) {
data[0][i] = realRowData[i];
data[1][i] = fakeRowData[i];
}
//set up tableModel
JTable table = new JTable();
table.setModel(new DefaultTableModel(data,
new String[] { "ID #", "Group #", "version", "Action" })
{
Class[] types = new Class[] {
Integer.class, String.class, String.class, String.class
};
boolean[] editable = new boolean[] {
false, false, true, false
};
#Override
public Class getColumnClass(int columnIndex) {
return types[columnIndex];
}
#Override
public boolean isCellEditable(int rowIndex, int columnIndex) {
return editable[columnIndex];
}
});
//set custom renderer on table
table.setDefaultRenderer(String.class, new CustomTableRenderer());
//create frame to place table
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setMinimumSize(new Dimension(400, 400));
JScrollPane scrollPane = new JScrollPane();
scrollPane.setViewportView(table);
f.add(scrollPane);
f.pack();
f.setVisible(true);
}
//MAIN
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
//Custom DefaultTableCellRenderer
public static class CustomTableRenderer extends DefaultTableCellRenderer {
public Component getTableCellRenderer(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column)
{
Component c = super.getTableCellRendererComponent(table, value, isSelected,
hasFocus, row, column);
String versionVal = table.getValueAt(row, IMPORTANT_COLUMN).toString();
if(versionVal.contains("FAKE")) {
//set to red bold font
c.setForeground(Color.RED);
c.setFont(new Font("Dialog", Font.BOLD, 12));
} else {
//stay at default
c.setForeground(Color.BLACK);
c.setFont(new Font("Dialog", Font.PLAIN, 12));
}
return c;
}
}
}
My goal is to highlight any value in the version column that contains the word FAKE in a red bold text.

I've extended DefaultTableCellRenderer but I don't believe it is being applied
Some simple debugging tips:
Add a simple System.out.println(...) to the method you think should be invoked
When overriding a method, make sure you use the #Override annotation (you used it in the TableModel class, but not your renderer class).
Your problem is a typing mistake because you are not overriding the proper method:
#Override
// public Component getTableCellRenderer(...) // this is wrong
public Component getTableCellRendererComponent(...)
The override annotation will display a compile message. Try it before changing the code.
Also, your first column is NOT an Integer class. Just because it contains String representations of an Integer does not make it an Integer. You need to add an Integer object to the model.

Replace your custom table cell rendere with the below.
Explanations are in comments. Basically, you should override getTableCellRendererComponent then check for correct column (there may be other methods instead of checking header value), then set cell depending on color.
Do not forget last else block to set color to default if it is not the column you want.
//Custom DefaultTableCellRenderer
public static class CustomTableRenderer extends DefaultTableCellRenderer {
// You should override getTableCellRendererComponent
#Override
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column) {
Component c = super.getTableCellRendererComponent(table, value, isSelected,
hasFocus, row, column);
// Check the column name, if it is "version"
if (table.getColumnName(column).compareToIgnoreCase("version") == 0) {
// You know version column includes string
String versionVal = (String) value;
if (versionVal.contains("FAKE")) {
//set to red bold font
c.setForeground(Color.RED);
c.setFont(new Font("Dialog", Font.BOLD, 12));
} else {
//stay at default
c.setForeground(Color.BLACK);
c.setFont(new Font("Dialog", Font.PLAIN, 12));
}
} else {
// Here you should also stay at default
//stay at default
c.setForeground(Color.BLACK);
c.setFont(new Font("Dialog", Font.PLAIN, 12));
}
return c;
}
}

Usability features for JComboBox within JTable

I'm trying to build a table which includes JComboBoxes as both the renderer and editor components. This mostly works fine, however there are two things I can't seem to solve.
Tabbing between cells should make the JComboBox active
Clicking the drop-down arrow should immediately open the option list
Regarding 1, the editable combo should place focus within the embedded text field, the fixed combo should allow the down arrow to open the list of options.
Regarding 2, I find that this sometimes works depending on what other cell is currently active, but other times I have to double click. I cannot make this behaviour consistent.
For convenience I have included a clear example which (I believe) uses the recommended approach for embedding JComboBoxes within Jtables.
Thank you for constructive advice.
import java.awt.Component;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
public class TableCombos
{
public static void main(String[] args)
{
JFrame frame = new JFrame("Frame");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
AbstractTableModel model = new DefaultTableModel()
{
String[] columnHeaders = new String[]{"label", "combo-edit", "combo-fixed"};
Class<?>[] columnClasses = new Class<?>[]{String.class, Double.class, Double.class};
List<Object[]> data = new ArrayList<>();
{
data.add(new Object[]{"row 1", 1.0d, 2.0d});
data.add(new Object[]{"row 2", 2.0d, 3.0d});
}
#Override
public int getColumnCount()
{
return columnHeaders.length;
}
#Override
public boolean isCellEditable(int row, int column)
{
return column != 0;
}
#Override
public int getRowCount()
{
if (data == null) // race condition
return 0;
return data.size();
}
#Override
public Object getValueAt(int row, int column)
{
return data.get(row)[column];
}
#Override
public void setValueAt(Object aValue, int row, int column)
{
data.get(row)[column] = aValue;
}
#Override
public Class<?> getColumnClass(int column)
{
return columnClasses[column];
}
#Override
public String getColumnName(int column)
{
return columnHeaders[column];
}
};
JTable table = new JTable(model);
table.setSurrendersFocusOnKeystroke(true);
TableColumn c1 = table.getColumnModel().getColumn(1);
TableColumn c2 = table.getColumnModel().getColumn(2);
JComboBox<Double> editorComboEditable = new JComboBox<>(new Double[]{1.0d, 2.0d, 3.0d});
editorComboEditable.setEditable(true);
c1.setCellEditor(new DefaultCellEditor(editorComboEditable));
c2.setCellEditor(new DefaultCellEditor(new JComboBox<>(new Double[]{1.0d, 2.0d, 3.0d})));
final JComboBox<Double> rendererComboEditable = new JComboBox<>(new Double[]{1.0d, 2.0d, 3.0d});
rendererComboEditable.setEditable(true);
final JComboBox<Double> rendererComboFixed = new JComboBox<>(new Double[]{1.0d, 2.0d, 3.0d});
c1.setCellRenderer(new TableCellRenderer()
{
#Override
public Component getTableCellRendererComponent(JTable t, Object value, boolean isSelected, boolean hasFocus, int row, int column)
{
rendererComboEditable.setSelectedItem(value);
return rendererComboEditable;
}
});
c2.setCellRenderer(new TableCellRenderer()
{
#Override
public Component getTableCellRendererComponent(JTable t, Object value, boolean isSelected, boolean hasFocus, int row, int column)
{
rendererComboFixed.setSelectedItem(value);
return rendererComboFixed;
}
});
frame.getContentPane().add(new JScrollPane(table));
frame.pack();
frame.setVisible(true);
}
}

Both of your issues be resolved by overriding the DefaultCellEditor#isCellEditable method and returning true
You may need to set JTable#setSurrendersFocusOnKeystroke to true as well
Update
The short answer is "It's messy". The long answer is "it's very messy"
I did a "continuos editing" process some time back. Basically, I overrode the Enter and Tab key bindings.
What I'd did was basically stop any active cell editor, take note of the current cell and then tried to finding the next editable cell, looping back around to the start (cell 0x0) if required.
When I found a editable cell, I called JTable#esitCellAt to start editing the cell.
To get the popup to be visible when the cell starts editing, you will need to override the addNotify method of the JComboBox and, using SwingUtilities#invokeLater, set the popup visible

Customizing my Cell Renderer to change one cells colour?

note: this code is not mine, I have taken it from another site and i'm simply trying to modify it.
I have a JTable with a load of details however, I want it so that when I change a particular cell for the first cell to change colour. Currently this code just highlights the row when I click on it, but I want it so that if I change one of the values to another number, the name cell for example to change red. I have tried a few things (if statements) but can't seem to work it. Any help would be great.
import javax.swing.*;
import javax.swing.table.*;
import java.awt.*;
public class CustomCellRenderer{
JTable table;
TableColumn tcol;
public static void main(String[] args) {
new CustomCellRenderer();
}
public CustomCellRenderer(){
JFrame frame = new JFrame("Creating a Custom Cell Reanderer!");
JPanel panel = new JPanel();
String data[][] = {{"Vinod","Computer","3"},
{"Rahul","History","2"},
{"Manoj","Biology","4"},
{"Sanjay","PSD","5"}};
String col [] = {"Name","Course","Year"};
DefaultTableModel model = new DefaultTableModel(data,col);
table = new JTable(model);
tcol = table.getColumnModel().getColumn(0);
tcol.setCellRenderer(new CustomTableCellRenderer());
tcol = table.getColumnModel().getColumn(1);
tcol.setCellRenderer(new CustomTableCellRenderer());
tcol = table.getColumnModel().getColumn(2);
tcol.setCellRenderer(new CustomTableCellRenderer());
JTableHeader header = table.getTableHeader();
header.setBackground(Color.yellow);
JScrollPane pane = new JScrollPane(table);
panel.add(pane);
frame.add(panel);
frame.setSize(500,150);
frame.setUndecorated(true);
frame.getRootPane().setWindowDecorationStyle(JRootPane.PLAIN_DIALOG);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public class CustomTableCellRenderer extends DefaultTableCellRenderer{
public Component getTableCellRendererComponent (JTable table,
Object obj, boolean isSelected, boolean hasFocus, int row, int column) {
Component cell = super.getTableCellRendererComponent(
table, obj, isSelected, hasFocus, row, column);
if (isSelected) {
cell.setBackground(Color.green);
}
else {
if (row % 2 == 0) {
cell.setBackground(Color.lightGray);
}
else {
cell.setBackground(Color.lightGray);
}
}
return cell;
}
}
}

If you know row number you want to highlight just add in the end of the getTableCellRendererComponent method
if (row==theRowNumberToHighlight && column=0) {
cell.setForeground(Color.red);
}

Assuming your table model extends AbstractTableModel, extend TableModelListener. Use the following tableChanged method to figure out when to call your renderer:
public void tableChanged(TableModelEvent e)
{
if (e.getColumn() == columnYouAreChecking && e.getFirstRow() == rowYouAreChecking && e.getLastRow() == rowYouAreChecking)
{
// Change cell color here.
}
}
This code will get called every time the data in your table changes.

Table Cell Editor issue

I'm building a custom table cell editor so it adjusts row height during editing. I have this code, but instead of resizing the cell it seams to resize the whole panel, or the frame. When I try to enter a character in a cell the main frame width narrows down to a couple of pixels.
Can anyone see the problem?
class MyTableCellEditor extends AbstractCellEditor implements TableCellEditor {
MyTextpane component = new MyTextpane();
MyTable table;
private int row;
private int col;
public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected,
int rowIndex, int vColIndex) {
((MyTextpane) component).setText((String) value);
component.addKeyListener(new KeyListener1());
this.table =(MyTable) table;
this.row = rowIndex;
this.col = vColIndex;
return component;
}
public Object getCellEditorValue() {
return ((MyTextpane) component).getText();
}
public class KeyListener1 implements KeyListener {
#Override
public void keyTyped(KeyEvent ke) {
}
#Override
public void keyPressed(KeyEvent ke) {
}
#Override
public void keyReleased(KeyEvent ke) {
adjustRowHeight(table, row, col);
}
private java.util.List<java.util.List<Integer>> rowColHeight = new ArrayList<java.util.List<Integer>>();
private void adjustRowHeight(JTable table, int row, int column) {
//The trick to get this to work properly is to set the width of the column to the
//textarea. The reason for this is that getPreferredSize(), without a width tries
//to place all the text in one line. By setting the size with the with of the column,
//getPreferredSize() returnes the proper height which the row should have in
//order to make room for the text.
int cWidth = table.getTableHeader().getColumnModel().getColumn(column).getWidth();
setSize(new Dimension(cWidth, 1000));
int prefH = getPreferredSize().height;
while (rowColHeight.size() <= row) {
rowColHeight.add(new ArrayList<Integer>(column));
}
java.util.List<Integer> colHeights = rowColHeight.get(row);
while (colHeights.size() <= column) {
colHeights.add(0);
}
colHeights.set(column, prefH);
int maxH = prefH;
for (Integer colHeight : colHeights) {
if (colHeight > maxH) {
maxH = colHeight;
}
}
if (table.getRowHeight(row) != maxH) {
table.setRowHeight(row, maxH);
}
}
}
}

have look at
my answer about doLayout(could be fired from CellEditor)
or (more than confortable way to use TextUtils) comment by #kleopatra about getPreferredSize
this could (very) confusing the users,
because I miss JScrollPane, there have to override MaxSize, max size is height & weight for JScrollPane, otherwise part of CellEditor can going outside of screeens bounds .........,
don't do that, put there JScrollPane with JTextComponents, override PreferredSize for CellEditor,
everything are wrong, my view,
create applications modal popup window (based only on JDialog, becasue JWindow doesn't alloved input to the JTextComponent) with JTextComponent, implements there KeyBindings for ESC key, the same for lost Fucus for JDialog, then could be undecorated without any issue
put there Save JButton
output from Save Button reditect to the selected cell, you can't lost focus from application modal inside JTable
contents should be formatted, filtered, modified one JDialog for all cells from JTable

As an alternative to resizing the row while editing, consider TablePopupEditor, which uses JTextArea.

JTable Calls Custom Cell Renderer Method... Continuously

Compilable source can be found at: http://www.splashcd.com/jtable.tar
I'm new to the language, so I'm not sure if this is acceptable behavior or not.
I created a JTable to display a row for each message received (it receives about
one every 20 seconds). One of the table columns can contain a large amount of
text, so I created a custom cell renderer which word wraps and sets the row
height accordingly.
All that works as expected, except that once the table displays its first row,
it calls the cell renderer about ten times a second... until the user closes the
table.
Once I get approx 20 rows in there, the table gets fairly sluggish, taking 2-8
seconds to resize a column, scoll up or down, or render a selected row with the
selected background color.
I inserted a print statement inside the renderer, so I can see how many times
the getTableCellRendererComponent method is being called.
I disabled tool tips, and disabled all cell editing. I do have a listener that
scrolls the view to the last row when either a new row is added or the table is
resized.
Should the getTableCellRendererComponent method be called several times a second
when I'm just viewing the screen (not touching mouse or keyboard)?
TIA

aaaaach
you need doLayout(),
next level :-), then there you can to set Maximum visible rows for JTextComponents too, with little effort
doLayout()
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.text.*;
//http://tips4java.wordpress.com/2008/10/26/text-utilities/
public class AutoWrapTest {
public JComponent makeUI() {
String[] columnNames = {" Text Area Cell Renderer "};
Object[][] data = {
{"123456789012345678901234567890"},
{"dddddddddddddddddddddddddddddddddddddddddddddddddddddddddx"},
{"----------------------------------------------0"},
{">>>>>>>>>>>>>dddddddddddddddddddddddddddddddddddddddddddddddddd"
+ "dddddddxdddddddddddddddddddddddddddddddddddddddddddddd"
+ "dddddddddddx>>>>>>>>>>>>>>>>>>>>>>>>>|"},
{">>>>>>>>>>>>ddddddddddddddddddddddddddddddddddddddddddddddddddd"
+ "ddddddx>>>>>>>>>>>>>>>>>>>>>>>>>>|"},
{"a|"},
{">>>>>>>>bbbb>>>>>>>>>>>>>>>>>>>|"},
{">>>>>>>>>>>>>>>>>>|"},
{">>>>>>>>>>>>>dddddddddddddddddddddddddddddddddddddddddddddddddd"
+ "dddddddxdddddddddddddd123456789012345678901234567890dddddd"
+ "dddddddddddddddddddddddddddddddddddddx>>>>>>>>>>>>>>>>>>>>"
+ ">>>>>|"},
{">>>>>>>>>>>>>dddddddddddddd123456789012345678901234567890dddddd"
+ "dddddddddddddddddddddddddddddddddddddxdddddddddddddd123456"
+ "789012345678901234567890dddddddddddddddddddddddddddddddddd"
+ "ddddd123456789012345678901234567890ddddx>>>>>>>>>>>>>>>>>>"
+ ">>>>>>>|"},};
TableModel model = new DefaultTableModel(data, columnNames) {
private static final long serialVersionUID = 1L;
#Override
public boolean isCellEditable(int row, int column) {
return false;
}
};
JTable table = new JTable(model) {
private static final long serialVersionUID = 1L;
#Override
public void doLayout() {
TableColumn col = getColumnModel().getColumn(0);
for (int row = 0; row < getRowCount(); row++) {
Component c = prepareRenderer(col.getCellRenderer(), row, 0);
if (c instanceof JTextArea) {
JTextArea a = (JTextArea) c;
int h = getPreferredHeight(a) + getIntercellSpacing().height;
if (getRowHeight(row) != h) {
setRowHeight(row, h);
}
}
}
super.doLayout();
}
private int getPreferredHeight(JTextComponent c) {
Insets insets = c.getInsets();
View view = c.getUI().getRootView(c).getView(0);
int preferredHeight = (int) view.getPreferredSpan(View.Y_AXIS);
return preferredHeight + insets.top + insets.bottom;
}
};
table.setEnabled(false);
table.setShowGrid(false);
table.setTableHeader(null);
table.getColumnModel().getColumn(0).setCellRenderer(new TextAreaCellRenderer());
//table.setPreferredScrollableViewportSize(table.getPreferredSize());
JScrollPane sp = new JScrollPane(table);
sp.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
sp.setPreferredSize(new Dimension(250, 533));
JPanel p = new JPanel(new BorderLayout());
p.add(sp);
return p;
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGUI();
}
});
}
public static void createAndShowGUI() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
f.getContentPane().add(new AutoWrapTest().makeUI());
f.setLocation(100, 100);
f.pack();
f.setVisible(true);
}
}
class TextAreaCellRenderer extends JTextArea implements TableCellRenderer {
private static final long serialVersionUID = 1L;
private final Color evenColor = new Color(230, 240, 255);
public TextAreaCellRenderer() {
super();
setLineWrap(true);
setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
}
#Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
if (isSelected) {
setForeground(table.getSelectionForeground());
setBackground(table.getSelectionBackground());
} else {
setForeground(table.getForeground());
setBackground(table.getBackground());
setBackground((row % 2 == 0) ? evenColor : getBackground());
}
setFont(table.getFont());
setText((value == null) ? "" : value.toString());
return this;
}
}

To get the most performance out of a TableCellRenderer, make sure you're not creating a new instance of a component every time getTableCellRenderer is called. Make the components once and save them as fields of the class.
Also, you'll want to make sure each of the Components you use have the following methods overridden to do nothing:
validate
invalidate
revalidate
repaint
firePropertyChange
(and you probably want to hard code isOpaque).
For more information see: http://docs.oracle.com/javase/6/docs/api/javax/swing/tree/DefaultTreeCellRenderer.html

The problem seems to stem from having JTable's setRowHeight() inside the custom cell renderer, as it calls the custom cell renderer, throwing it into an infinite loop.
I had to add in a check to see if the current row height matched the calculated word wrapped row height. If it did, I didnt try to setRowHeight() again.
Corrected Code:
import java.awt.Component;
import javax.swing.JTable;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.table.TableCellRenderer;
//custom cell renderer for word wrapping, but if you use, you have to
//implement zebra striping functionality which the default renderer has
public class LineWrapCellRenderer extends JTextArea implements TableCellRenderer
{
private int numOfTimesCalled;
#Override
public Component getTableCellRendererComponent(
JTable table,
Object value,
boolean isSelected,
boolean hasFocus,
int row,
int column)
{
System.out.println("Line Wrap Cell Renderer Called: " + numOfTimesCalled++);
System.out.println("row:"+ row + ", col:" + column);
//set up the row size based on the number of newlines in the text in the cell
int fontHeight = this.getFontMetrics(this.getFont()).getHeight();
int numWraps = value.toString().split("\r\n|\r|\n").length;
int rowHeight = fontHeight * numWraps;
//if the calculated rowHeight is the same as the row height of row,
// then don't call setRowHeight again, as doing so will throw us into
// an infinite loop
if(rowHeight != table.getRowHeight(row))
{
table.setRowHeight(row, rowHeight);
//configure word wrapping
setWrapStyleWord(true);
setLineWrap(true);
//use the table's font
setFont(table.getFont());
}
//zebra striping, because whatever cell uses this renderer loses the
//default cell renderer zebra striping
if(isSelected)
{
setBackground(table.getSelectionBackground());
}
else
{
if(row%2 == 1)
{
setBackground(UIManager.getColor("Table.alternateRowColor"));
}
else
{
setBackground(table.getBackground());
}
}
this.setText(value.toString());
return this;
}
}