javaswingjtabletablecellrenderer
Rendering jtable cell foreground based on positive or negative values
I'm not sure how I should approach this, what I want to do is have these P&L cells foreground be green when the value is greater than 0 and red if less than 0. I know I need to use tablecellrenderer somehow I'm just not sure how to start.
This is the table settings:
tbl_positions = new WebTable(posdata, posHeaders)
{
public Component prepareRenderer(TableCellRenderer renderer,
int rowIndex, int vColIndex) {
Component c = super.prepareRenderer(renderer, rowIndex,
vColIndex);
if (rowIndex % 2 == 0 && !isCellSelected(rowIndex, vColIndex))
{
c.setBackground((new Color(216, 216, 216)));
}
else
{
if(!isCellSelected(rowIndex, vColIndex))
{
if(rowIndex != 21)
c.setBackground(getBackground());
else
c.setBackground((new Color(216, 249, 255)));
}
else
{
c.setBackground((new Color(0, 128, 255)));
}
}
if(vColIndex == 5 || vColIndex == 6 )
{
Integer intValue = (Integer) getValueAt(rowIndex, vColIndex);
c.setForeground(getColor(intValue));
}
else
{
c.setForeground(getForeground());
}
return c;
}
private Color getColor(Integer intValue)
{
Color color = null;
if (intValue > 0) {
color = Color.GREEN;
} else if (intValue < 0) {
color = Color.RED;
} else {
color = getForeground();
}
return color;
}
};
It's now working:
Solution
For something as simple as setting the foreground, you don't need a custom renderer. You can simply override prepareRenderer of the JTable. Something like
JTable table = new JTable(model) {
@Override
public Component prepareRenderer(TableCellRenderer renderer,
int row, int col) {
Component c = super.prepareRenderer(renderer, row, col);
if (col == PL_COLUMN) {
Integer intValue = (Integer) getValueAt(row, col);
c.setForeground(getColor(intValue));
} else {
c.setForeground(getForeground());
}
return c;
}
private Color getColor(int intValue) {
Color color = null;
if (intValue > 0) {
color = Color.GREEN;
} else if (intValue < 0) {
color = Color.RED;
} else {
color = getForeground();
}
return color;
}
};
Take some time to go over How to Use Tables: Editors and Renderers for more information on custom rendering
UPDATE: full demo
import java.awt.Color;
import java.awt.Component;
import java.util.Random;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;
public class TestTableRenderer {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
public void run() {
NikeSaysJustDoIt();
}
});
}
private static void NikeSaysJustDoIt() {
Random random = new Random();
Object[][] data = new Object[30][7];
for (int i = 0; i < data.length; i++) {
for (int j = 0; j < data[i].length; j++) {
data[i][j] = (random.nextInt(65536) - 32768);
}
}
String[] cols = new String[] { "col", "col", "col", "col", "col", "col", "col" };
DefaultTableModel model = new DefaultTableModel(data, cols);
JTable table = new JTable(model) {
@Override
public Component prepareRenderer(TableCellRenderer renderer,
int row, int col) {
Component c = super.prepareRenderer(renderer, row, col);
if (col == 5 || col == 6) {
Integer intValue = (Integer) getValueAt(row, col);
c.setForeground(getColor(intValue));
} else {
c.setForeground(getForeground());
}
return c;
}
private Color getColor(int intValue) {
Color color = null;
if (intValue > 0) {
color = Color.GREEN;
} else if (intValue < 0) {
color = Color.RED;
} else {
color = getForeground();
}
return color;
}
};
JOptionPane.showMessageDialog(null, new JScrollPane(table));
}
}
UPDATE 2: Using all double values and a NumberFormat for the last row.
I left a bunch of comments that will help you to understand the code. Note that you may want to have to formatters. The image you have displays to different formats. One with currency sign and one without. Also some of your values are integers and some are decimals. So you will most likely need two formatters to get it the way you want.
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.NumberFormat;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
public class TableFormatRenderDemo {
public TableFormatRenderDemo() {
JFrame frame = new JFrame();
frame.add(new JScrollPane(createTable()));
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
/*
* We are using all double values. We leave the rendering to
* the renderer. The NumberFormat is used to format the text.
*/
private JTable createTable() {
Object[][] data = new Object[][] {
{ "AUD", 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 },
{ "CAD", 0.0, 0.0, 0.0, 0.0, 45.00, -0.35 },
{ "CHF", 0.897, -1, 0.896, 0.0, -120.00, 0.00 },
{ "CHK", 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 },
{ "Total", null, null, null, null, 20125.00, 0.00 } };
String[] cols = { "col 1", "col 2", "col 3", "col 4", "col 5", "col 6",
"col 7" };
DefaultTableModel model = new DefaultTableModel(data, cols);
JTable table = new JTable(model) {
@Override
public Dimension getPreferredScrollableViewportSize() {
return getPreferredSize();
}
};
// Set the custom renerer
table.setDefaultRenderer(Object.class, new NumberFormatRenderer());
return table;
}
private NumberFormat getFormatter() {
NumberFormat formatter = NumberFormat.getCurrencyInstance();
DecimalFormatSymbols decimalFormatSymbols = ((DecimalFormat) formatter)
.getDecimalFormatSymbols();
decimalFormatSymbols.setCurrencySymbol("$");
((DecimalFormat) formatter)
.setDecimalFormatSymbols(decimalFormatSymbols);
return formatter;
}
/**
* Custom renderer we use for the table
*/
private class NumberFormatRenderer extends DefaultTableCellRenderer {
private static final long serialVersionUID = 5152961981995932787L;
private static final int PL_USD_COL = 5;
private static final int DAILY_PL_COL = 6;
// TODO We may want to have a setter for this formatter
private final NumberFormat formatter = getFormatter();
private final Color POSITIVE_COLOR = new Color(65, 185, 62);
private final Color NEGATIVE_COLOR = Color.RED;
private final Color LAST_ROW_COLOR = Color.CYAN;
private final Color ALT_ROW_COLOR = Color.LIGHT_GRAY;
public Component getTableCellRendererComponent(JTable table,
Object value, boolean isSelected, boolean hasFocus, int row,
int column) {
super.getTableCellRendererComponent(table, value, isSelected,
hasFocus, row, column);
renderAlternateBackground(row, table.getBackground(), table.getRowCount());
renderForeground(row, column, table.getForeground(),
table.getRowCount(), value);
// Formats the last row with the given NumberFormat
if (row == table.getRowCount() - 1 && column != 0 && value != null) {
setText(formatter.format((Double) value));
}
// Centers the text
setHorizontalAlignment(CENTER);
return this;
}
/**
* Renders the foreground. Render only if column is one of
* the predefined "PL" columns, using the helper method
* <code>getColor</code> to determine the color to render based on the
* <code>value</code>.
*
* @param row
* @param col
* @param tableForeground
* @param rowCount
* @param value
*/
private void renderForeground(int row, int col, Color tableForeground,
int rowCount, Object value) {
if (col == PL_USD_COL || col == DAILY_PL_COL) {
setForeground(getColor((Double) value, tableForeground));
} else {
setForeground(tableForeground);
}
}
/**
* Helper method for the <code>renderForeground</code> method. Returns
* a <code>Color</code> base on the value.
* @param value
* @param tableForeground
* @return
*/
private Color getColor(double value, Color tableForeground) {
Color color = null;
if (value > 0) {
color = POSITIVE_COLOR;
} else if (value < 0) {
color = NEGATIVE_COLOR;
} else {
color = tableForeground;
}
return color;
}
/**
* Rendered alternate background color. Check for odd rows numbers.
* The last row is rendered as the select <code>LAST_ROW_COLOR</code> color.
* @param row
* @param tableBackground
* @param rowCount
*/
private void renderAlternateBackground(int row, Color tableBackground,
int rowCount) {
if (row % 2 != 0) {
setBackground(ALT_ROW_COLOR);
} else if (row == (rowCount - 1)) {
setBackground(LAST_ROW_COLOR);
} else {
setBackground(tableBackground);
}
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TableFormatRenderDemo();
}
});
}
}
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