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Cells with centered value and background based on value

here is my problem
I read a DB and show the data via the renderer. Shown data must be centered and bgcolor must change according to the value of the cell.
Following is the renderer. First table.getColumnModel() shows the centered value, second one calls a customer renderer to change the color. If I remove the comment on the second call I get the bgcolor but not the centered value and viceversa
for (int row = 0; row < table.getColumnCount(); row++) {
DefaultTableCellRenderer centerRenderer = new DefaultTableCellRenderer();
centerRenderer.setHorizontalAlignment(JLabel.CENTER);
table.getColumnModel().getColumn(row).setCellRenderer(centerRenderer);
//table.getColumnModel().getColumn(row).setCellRenderer(new CustomRenderer());
}
This is the Custom renderer
class CustomRenderer extends DefaultTableCellRenderer
{
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
{
Component cellComponent = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
if(table.getValueAt(row, column).equals("A")){
cellComponent.setBackground(Color.YELLOW);
} else if(table.getValueAt(row, column).equals("B")){
cellComponent.setBackground(Color.GRAY);
}
else {cellComponent.setBackground(Color.white);}
return cellComponent;
}
}
How can I obtain a colored and center cell?
Than you
paps

Here a short snippet demonstrating what I think you are trying to achieve:
public class Testing {
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Testing();
}
});
}
public Testing() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
String[] colNames = { "Col1", "Col2" };
Object[][] data = { { "A", "B" }, { "B", "C" } };
JTable table = new JTable(data, colNames);
CustomRenderer renderer = new CustomRenderer();
renderer.setHorizontalAlignment(JLabel.CENTER);
// table.setDefaultRenderer(String.class, renderer); // if you want to only
// color and center all strings
for (int col = 0; col < table.getColumnCount(); col++) {
// if you want to color and center every entry of the table
table.getColumnModel().getColumn(col).setCellRenderer(renderer);
}
panel.add(table);
frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
class CustomRenderer extends DefaultTableCellRenderer {
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row,
int column) {
Component cellComponent = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
cellComponent.setBackground(Color.white); // white if not "A" or "B"
if (value instanceof String) {
String temp = (String) value;
if (temp.equals("A")) {
cellComponent.setBackground(Color.YELLOW);
} else if (temp.equals("B")) {
cellComponent.setBackground(Color.GRAY);
}
}
return cellComponent;
}
}
}
The result will look like:
Note that your custom renderer only has to be created once, not on every loop. The issue in your code was, that you didn't use your own renderer, but a DefaultTableCellRenderer instead. Also, if you want to only use the custom rendering on a specific class type, e.g. only on String objects, you can use the commented out line instead of iterating through all columns of the table.
And of course you can add further restrictions to the CustomRenderer according to your needs.

How Can I hide same value in the JTable by using DefaultTableCellRenderer

I make a timetable with Java, but I cannot solve one problem.
I want to change the foreground color as same as background color or Hiding a value, when some cells have a same value at first detected cell.
Like this...
Here's what I made...
(Sorry about Korean words...)
So, I want to use a DefaultTableCellRenderer, but I can't find a good example about this.
And, I don't know how DefaultTableCellRenderer works. Can't find any explains about that...
So, I want to ask a favor about that problem.
Here's my code:
public class subject_table_renderer extends DefaultTableCellRenderer
{
private Object subject_name = "";
#Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
{
Component cell = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
if (! isSelected)
{
if(value.equals("")){
cell.setBackground(Color.WHITE);
}
else{
String[] temp = MainFrame.find_list((String)value, MainFrame.subject);
//take a subject_list for decide background color
if(!value.equals(subject_name)){
subject_name = value;
cell.setBackground(get_rand_color(cell, Integer.parseInt(temp[6])));
}
else{
cell.setBackground(get_rand_color(cell, Integer.parseInt(temp[6])));
cell.setForeground(get_rand_color(cell, Integer.parseInt(temp[6])));
}
}
}
return cell;
}

And, I don't know how DefaultTableCellRenderer works. Can't find any explains about that...
Maybe start with the Swing tutorial on Concepts: Editors and Renderers.
You can't use an instance variable to track the previous value because you can't be guaranteed that the rows will always be rendered in sequential order. For example if row 1 is selected and then you click on row 10, only rows 1 and 10 will be repainted.
So the solution is to compare the previous value in the render with code something like:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.table.*;
public class SSCCE extends JPanel
{
public SSCCE()
{
setLayout( new BorderLayout() );
JTable table = new JTable(10, 1);
table.setValueAt("one", 0, 0);
table.setValueAt("one", 1, 0);
table.setValueAt("two", 2, 0);
table.setValueAt("two", 3, 0);
table.setValueAt("two", 4, 0);
table.setValueAt("three", 5, 0);
add( new JScrollPane( table ) );
table.getColumnModel().getColumn(0).setCellRenderer( new DuplicateRenderer() );
}
/*
** Color the focused cell
*/
class DuplicateRenderer extends DefaultTableCellRenderer
{
#Override
public Component getTableCellRendererComponent(
JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
{
super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
if (row > 0 && value != null)
{
Object previous = table.getValueAt(row - 1, column);
if (value.equals(previous))
{
setText("");
}
}
return this;
}
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("SSCCE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new SSCCE());
frame.setLocationByPlatform( true );
frame.pack();
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater( () -> createAndShowGUI() );
/*
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
*/
}
}

Color JTable row

I use TableCellRenderer in a function to change the color of a row.
public void change_color(JTable tableName){
tableName.setDefaultRenderer(Object.class, new TableCellRenderer(){
private DefaultTableCellRenderer DEFAULT_RENDERER = new DefaultTableCellRenderer();
#Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
Component c = DEFAULT_RENDERER.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
c.setBackground(Color.RED);
//Add below code here
return c;
}
});
}
It changes the color of entire table. To call this function i use following condition.
if(ellapsed.getMinutes() > 30)
{
change_color(table_dineIn,ellapsed.getMinutes());
}
Cant figure out the problem. I have tried other codes to but nothing helped me.

The cell renderers in JTable, JList etc. are used like a stamp (see Editors and Renderers for details).
This means that usually, the same (identical) JComponent is used for painting all the cells. This component is only filled with the appropriate contents before it is used for painting the cell. And when the background is set to RED, it will remain red until it is set to a different color.
I'm not sure what you wanted to achieve by using this DEFAULT_RENDERER instance. You could simply inherit from DefaultTableCellRenderer and return the component (which is in fact the renderer itself) direcly. However, in any case, you'll have to include some code that makes sure that the appropriate color is set for every call, roughly like
....
if (shouldBeRed(row, column)) {
c.setBackground(Color.RED);
} else {
c.setBackground(notRed);
}
return c;
(note that this can actually be hidden in the call to the super method if you extend DefaultTableCellRenderer, but the details here depend on whether you'll keep this DEFAULT_RENDERER instance or not...)
You might also be interested in this example of blinking table cells, showing how several table cells may be assigned different colors based on certain criteria.
EDIT: An example. Although I usually try to avoid answereing questions like this with examples like this, because even for the slightest modification, you'll ask another question, which in this case will probably in the line of
how to un-highlight the row
how to highlight multiple rows
how to highlight multiple rows with different colors
...
You'll find answers to all these questions in https://stackoverflow.com/a/24556135/3182664 - in the meantime, I'll mark this question as a duplicate.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableCellRenderer;
public class TableRowColor
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("TableRowColor");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BorderLayout());
final JTable table = createTable();
JScrollPane scrollPane = new JScrollPane(table);
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
JButton changeColorButton = new JButton("Change color");
changeColorButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
changeColor(table, 1);
}
});
frame.getContentPane().add(changeColorButton, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private static JTable createTable()
{
String[] columnNames = { "First Name", "Last Name", "Sport", };
Object[][] data = { { "Kathy", "Smith", "Snowboarding" },
{ "John", "Doe", "Rowing" }, { "Sue", "Black", "Knitting" },
{ "Jane", "White", "Speed reading" }, { "Joe", "Brown", "Pool" } };
return new JTable(data, columnNames);
}
public static void changeColor(JTable table, final int coloredRow)
{
table.setDefaultRenderer(Object.class, new DefaultTableCellRenderer()
{
#Override
public Component getTableCellRendererComponent(JTable table,
Object value, boolean isSelected, boolean hasFocus, int row,
int column)
{
super.getTableCellRendererComponent(table, value, isSelected,
hasFocus, row, column);
if (row == coloredRow)
{
setBackground(Color.RED);
}
else
{
setBackground(null);
}
return this;
}
});
table.repaint();
}
}

The following would color 30th row of the table:
public void change_color(JTable tableName){
tableName.setDefaultRenderer(Object.class, new TableCellRenderer(){
private DefaultTableCellRenderer DEFAULT_RENDERER = new DefaultTableCellRenderer();
#Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
Component c = DEFAULT_RENDERER.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
if (row == 30) {
c.setBackground(Color.RED);
}
return c;
}
});
}
Edit:
If you want to choose table color based on data, add that data to the the table model (e.g. a Time stored in particular column), then use the model in the renderer. For example:
static final int TIME_ELLAPSED_COL = ...;
...
if (((Time) table.getModel().getValueAt(row, TIME_ELLAPSED_COL)).getMinutes() > 30) {
c.setBackground(Color.RED);
}
...

Cell Renderer for JTable - coloured rows

I've been looking around for a solution to this and I can't make head nor tail from various places of how to get my table to do coloured rows without asking my own question.
From every place I've looked I gather I need to use a cell renderer but the problem is I don't know how to apply it to my own situation.
So I have a simple JTable with 3 columns and I simply want each row to be highlighted in either green, yellow or red depending on the value of a separate variable (not displayed in the table).
It seems like it should be really simple but I can't get how to do it. If it helps my table is defined like:
studentTableModel = new DefaultTableModel(new Object[]{"Name", "StudentNo", "Part"}, 0);
jt_studentTable = new JTable(studentTableModel);
jt_studentTable.getColumnModel().getColumn(2).setPreferredWidth(10);
studentTableModel.addRow(new Object[]{"(empty)", "(empty)", "(empty)"});
JScrollPane jsp_tableScroller = new JScrollPane(jt_studentTable);
jsp_tableScroller.setPreferredSize(new Dimension(200,190));
middleCentrePanel.add(jsp_tableScroller);
The rows in the table change depending of the selection of a combo box.
Thanks in advance.

import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
public class RowRendering {
private static Object[] columnName = {"Yes", "No"};
private static Object[][] data = {
{"Y", "N"},
{"N", "Y"},
{"Y", "N"}
};
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
JTable table = new JTable(data, columnName);
table.getColumnModel().getColumn(0).setCellRenderer(new CustomRenderer());
table.getColumnModel().getColumn(1).setCellRenderer(new CustomRenderer());
frame.add(new JScrollPane(table));
frame.setTitle("Rendering in JTable");
frame.pack();
frame.setVisible(true);
}
};
EventQueue.invokeLater(r);
}
}
class CustomRenderer extends DefaultTableCellRenderer
{
private static final long serialVersionUID = 6703872492730589499L;
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
{
Component cellComponent = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
if(row == 0){
cellComponent.setBackground(Color.YELLOW);
} else if ( row == 1){
cellComponent.setBackground(Color.GRAY);
} else {
cellComponent.setBackground(Color.CYAN);
}
return cellComponent;
}
}

I simply want each row to be highlighted in either green, yellow or red depending on the value of a separate variable (not displayed in the table).
Renderers work on data in the table. That is components can only paint themselves when they have all the information needed to do the job.
So somehow you need to add the information to the table. This might be done be adding a 4th column that is hidden. Then the table still has access to the information required.
Then maybe you can use the suggestion in Table Row Renderering.

Maybe this works for you:
class MyCellRenderer extends DefaultTableCellRenderer {
String separatedVariable;
public MyCellRenderer(String separatedVariable) {
this.separatedVariable = separatedVariable;
}
#Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int col) {
Component c = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, col);
c.setBackground(Color.WHITE);
c.setForeground(Color.BLACK);
JLabel l = (JLabel) super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, col);
if (separatedVariable.equals("YOUR VALUE TO GREEN")) {
l.setBackground(Color.GREEN);
return l;
} else {
if (separatedValue.equals("YOUR VALUE TO YELLOW")) {
l.setBackground(Color.YELLOW);
return l;
} else if (separatedValue.equals("YOUR VALUE TO RED")) {
l.setBaground(Color.RED);
return l;
}
}
return c;
}
}

I just had this same question, but a bit more complicated, since I already had several different renderers for each column, depending on the datatype.
But I found that this works like a charm:
public class MyTable extends JTable {
#Override
public Component prepareRenderer(TableCellRenderer renderer, int row, int column) {
Component result = super.prepareRenderer(renderer, row, column);
if (mustBeYellow(row, column)) {
result.setBackground(Color.yellow);
}
return result;
}
private boolean mustBeYellow(int row, int column) {
// implement this depending on your data..
return false;
}
}

JTable cell with two data types

I have a column in JTable which should display two types: String OR ImageIcon, not both. Each cell in that column has own thread which calculates data. In the beginning I put to each cell an image(like waiting logo), then REPLACE(not append) the image with a string of calculated data. I tried to extend default TableCell renderer, but it displays image like object address(javax.swing.ImageIcon#342...) and then replaces with string. Another variant, it displays the image correctly, but replaces it with empty string(or it is not visible?).
How to set it up so the table displays cell content correctly according to type?
Here is what I have at the moment:
class IconAndStringRenderer extends DefaultTableCellRenderer {
private static final long serialVersionUID = 3606788739290618405L;
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column) {
super.getTableCellRendererComponent(table, value,
isSelected, hasFocus, row, column);
if (value instanceof Icon) {
setIcon((Icon) value);
setText("");
}
return this;
}
}
Here is JTable:
table = new JTable(model) {
private static final long serialVersionUID = 8058795799817761161L;
public Class<?> getColumnClass(int column) {
if (column == TARGET_COLUMN)
return ImageIcon.class;
else
return super.getColumnClass(column);
}
};
A few more questions:
How to set it so the text replaces the image, not write text after image(even if it's not visible);
How to set text color, I gonna use setForebackground(Color c), but if I use it, the image is not dislayed.
Is it possible to make it working with Jlabel? Set up required Jlabel(with image or text) in the thread which modifies a cell and just setValueAt(label, row, column);

You need a custom renderer which can understand both types you use.
For example
public class IconAndStringRenderer extends DefaultTableCellRenderer {
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column) {
super.getTableCellRendererComponent(table, value,
isSelected, hasFocus, row, column);
if (value instanceof Icon) {
setText("");
setIcon((Icon) value);
}
return this;
}
}
Try to set this class as your column renderer

The default renderer knows how to display both strings and icons. All you have to do is ensure that your TableModel returns the correct class from getColumnClass(), String.class and Icon.class, respectively. Examples may be found here.
Addendum: Here's a minimal example to illustrate the principle, based on default implementations.
Addendum: Not sure if it works when needed to return different classes for the same column.
If you really need to choose the renderer on a per-cell basis, override prepareRenderer(), as shown here.
import java.awt.EventQueue;
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.table.DefaultTableModel;
/** #see https://stackoverflow.com/a/14672312/230513 */
public class Test {
private static final Icon YES = UIManager.getIcon("InternalFrame.maximizeIcon");
private static final Icon NO = UIManager.getIcon("InternalFrame.closeIcon");
private void display() {
JFrame f = new JFrame("Test");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
DefaultTableModel model = new DefaultTableModel(
new Object[]{"Name", "Icon"}, 0) {
#Override
public Class<?> getColumnClass(int col) {
if (col == 1) {
return Icon.class;
} else {
return super.getColumnClass(col);
}
}
};
model.addRow(new Object[]{"One", YES});
model.addRow(new Object[]{"Two", NO});
final JTable table = new JTable(model);
table.setRowHeight(YES.getIconHeight() +2);
f.add(table);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new Test().display();
}
});
}
}

To take advantage of the default renderers you can override the getCellRenderer(...) method of JTable to return the appropriate renderer. Something like:
public TableCellRenderer getCellRenderer(int row, int column)
{
int modelColumn = convertColumnIndexToModel(column);
if (modelColumn == ???)
{
Class rowClass = getModel().getValueAt(row, modelColumn).getClass();
return getDefaultRenderer( rowClass );
}
else
return super.getCellRenderer(row, column);
}