Develop Reference

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;
}
}

Overriding createToolTip() in a custom CellRenderer

I'm trying to get a custom ToolTip for a specific column of a JTable. I've already created a CellRenderer (of which I've been changing other cell-specific attributes successfully):
private class CustomCellRenderer extends DefaultTableCellRenderer
{
private static final long serialVersionUID = 1L;
#Override
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column)
{
JComponent c = (JComponent) super.getTableCellRendererComponent(table, value,
isSelected, hasFocus, row, column);
if (value != null)
{
if(column == 1 && value instanceof Date)
{
final DateFormat df = new SimpleDateFormat("h:mm aa");
table.setValueAt(df.format(value), row, column);
}
else if(column == 2)
{
c.setToolTipText((String) value);
}
else if(column == 4)
{
final Mail m = main.selectedPage.messages.get(row);
JCheckBox checkBox;
if((Boolean) value)
{
checkBox = new JCheckBox()
{
#Override
public JToolTip createToolTip()
{
System.out.println("Passed");
return new ImageToolTip(m.getImage());
}
};
checkBox.setToolTipText(m.attachName);
}
else
checkBox = new JCheckBox();
checkBox.setSelected(((Boolean)value).booleanValue());
c = checkBox;
}
}
else
{
c.setToolTipText(null);
}
return c;
}
}
When I override any other JComponent's createTooltip() method like so, it all works fine outside of the Renderer.
checkBox = new JCheckBox()
{
#Override
public JToolTip createToolTip()
{
System.out.println("Passed");
return new ImageToolTip(m.getImage());
}
};
From what I can tell, the tooltip is created elsewhere, because "Passed" is never even printed. The checkBox.setToolTipText(m.attachName); only results in a default ToolTip with that String.
I've found someone with a similar question, but I can't say I completely understand the only resolving answer. Do I need to extend JTable and override getToolTipText(MouseEvent e)? If so, I'm not sure what with to get the correct (mine) Tooltip.
Please excuse any of my self-taught weirdness. Thanks in advance. :-)
EDIT:
Thanks to Robin, I was able to piece together something based on JTable's getToolTipText(MouseEvent e) code. I'll leave it here for anyone else with a similar problem. Again, I'm not sure it this it the best way to do it, so feel free to critique it below. :-)
messageTable = new JTable()
{
#Override
public JToolTip createToolTip()
{
Point p = getMousePosition();
// Locate the renderer under the event location
int hitColumnIndex = columnAtPoint(p);
int hitRowIndex = rowAtPoint(p);
if ((hitColumnIndex != -1) && (hitRowIndex != -1))
{
TableCellRenderer renderer = getCellRenderer(hitRowIndex, hitColumnIndex);
Component component = prepareRenderer(renderer, hitRowIndex, hitColumnIndex);
if (component instanceof JCheckBox)
{
Image img = main.selectedPage.messages.get(hitRowIndex).getImage();
if(((JCheckBox) component).isSelected())
return new ImageToolTip(img);
}
}
return super.createToolTip();
}
}

You are not able to create tooltip for checkbox inside cell renderer. Actually that component doesn't exists at the moment you are trying to move mouse over it. It is just an image. You need to create tooltip for your JTable
private void tableMouseMoved(java.awt.event.MouseEvent evt) {
String toolTipText;
int row = table.rowAtPoint(evt.getPoint());
int column = table.columnAtPoint(evt.getPoint());
if (row >= 0) {
Object o = table.getValueAt(row, column);
if (column == YourTableModel.COLUMN_INDEX_WITH_CHECKBOX) {
Boolean value = (Boolean) o;
if (value == Boolean.TRUE) {
toolTipText = "Tooltip text for true value";
} else {
toolTipText = "Tooltip text for false value";
}
}
}
}
And you need to register listener for MouseEvent of course:
javax.swing.JTable table = new JTable();
table.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
public void mouseMoved(java.awt.event.MouseEvent evt) {
tableMouseMoved(evt);
}
});

The reason that the JTable does not use your tooltip can be seen in the implementation. The JTable will indeed use the component returned by the renderer, but it will ask it for its tooltip text. So only settings a custom tooltip text will work if you stick to the default JTable implementation. Just a quick copy-paste of the relevant part of the JTable source code to illustrate this:
if (component instanceof JComponent) {
// Convert the event to the renderer's coordinate system
Rectangle cellRect = getCellRect(hitRowIndex, hitColumnIndex, false);
p.translate(-cellRect.x, -cellRect.y);
MouseEvent newEvent = new MouseEvent(component, event.getID(),
event.getWhen(), event.getModifiers(),
p.x, p.y,
event.getXOnScreen(),
event.getYOnScreen(),
event.getClickCount(),
event.isPopupTrigger(),
MouseEvent.NOBUTTON);
tip = ((JComponent)component).getToolTipText(newEvent);
}
So yes, you will have to override the JTable method if you really want an image as tooltip for your check box.
On a side-note: your renderer code has weird behavior. The
final DateFormat df = new SimpleDateFormat("h:mm aa");
table.setValueAt(df.format(value), row, column);
seems incorrect. You should replace the setValueAt call by a
JLabel label = new JLabel();//a field in your renderer
//in the getTableCellRendererComponent method
label.setText( df.format( value ) );
return label;
or something similar. The renderer should not adjust the table values, but create an appropriate component to visualize the data. In this case a JLabel seems sufficient. And as Stanislav noticed in the comments, you should not constantly create new components. That defeats the purpose of the renderer which was introduced to avoid creating new components for each row/column combination. Note that the method is called getTableCellRendererComponent (emphasis on get) and not createTableCellRendererComponent

Scrollable Cells in JTable

I have a Jtable in which I have to show some big data. I cann't increase the size of the Cells So I need to add a scrollbar in each cell of the table through which I can scroll the text of cells.
I have tried to add a Custom Cell Renderer
private class ExtendedTableCellEditor extends AbstractCellEditor implements TableCellEditor
{
JLabel area = new JLabel();
String text;
public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int rowIndex, int vColIndex)
{
area.setText(text);
return new JScrollPane(area);
}
public Object getCellEditorValue()
{
return text;
}
}
Now I am able to see the Scroll bar on the cells but not able to click and scroll them.
Any suggestions to this issue will be great.
Thanks in Advance.

Adding a JScrollPaneand placing the JLabel in the JScrollPane solved the issue. So I would like to share it with you all.
private class ExtendedTableCellEditor extends AbstractCellEditor implements TableCellEditor
{
JLabel _component = new JLabel();
JScrollPane _pane = new JScrollPane(_component, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
/**
* Returns the cell editor component.
*
*/
public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int rowIndex, int vColIndex)
{
if (value == null) return null;
_component.setText(value != null ? value.toString() : "");
_component.setToolTipText(value != null ? value.toString() : "");
_component.setOpaque(true);
_component.setBackground((isSelected) ? Color.BLUE_DARK : Color.WHITE);
_component.setForeground((isSelected) ? Color.WHITE : Color.BLACK);
_pane.setHorizontalScrollBar(_pane.createHorizontalScrollBar());
_pane.setVerticalScrollBar(_pane.createVerticalScrollBar());
_pane.setBorder(new EmptyBorder(0,0,0,0));
_pane.setToolTipText(value != null ? value.toString() : "");
return _pane;
}
public Object getCellEditorValue()
{
return _component.getText();
}
}