JTable Multiple Header Rows
I am using a JTable in my application and wish to have 2 rows for headings, similar to this:
Is this even possible or will I have to do something else? If so, what? Using Supertitle-titleA, SuperTitle-titleB will take up too much space and make information redundant.
Answer
We had the same requirement in our last project. What I have found is an Implementation for a GroupableTableHeader on java2s.com. However, I have pimped it a bit, although I cannot recall what exactly. Beneath is the implementation of the three classes as how we use them.
ColumnGroup.java
import java.awt.Component;
import java.awt.Dimension;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.swing.JTable;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
/**
* ColumnGroup
*
* @version 1.0 20.10.1998
* @author Nobuo Tamemasa
*/
public class ColumnGroup {
protected TableCellRenderer renderer;
protected List<TableColumn> columns;
protected List<ColumnGroup> groups;
protected String text;
protected int margin = 0;
public ColumnGroup(String text) {
this(text, null);
}
public ColumnGroup(String text, TableCellRenderer renderer) {
this.text = text;
this.renderer = renderer;
this.columns = new ArrayList<TableColumn>();
this.groups = new ArrayList<ColumnGroup>();
}
public void add(TableColumn column) {
columns.add(column);
}
public void add(ColumnGroup group) {
groups.add(group);
}
/**
* @param column
* TableColumn
*/
public List<ColumnGroup> getColumnGroups(TableColumn column) {
if (!contains(column)) {
return Collections.emptyList();
}
List<ColumnGroup> result = new ArrayList<ColumnGroup>();
result.add(this);
if (columns.contains(column)) {
return result;
}
for (ColumnGroup columnGroup : groups) {
result.addAll(columnGroup.getColumnGroups(column));
}
return result;
}
private boolean contains(TableColumn column) {
if (columns.contains(column)) {
return true;
}
for (ColumnGroup group : groups) {
if (group.contains(column)) {
return true;
}
}
return false;
}
public TableCellRenderer getHeaderRenderer() {
return renderer;
}
public void setHeaderRenderer(TableCellRenderer renderer) {
this.renderer = renderer;
}
public String getHeaderValue() {
return text;
}
public Dimension getSize(JTable table) {
TableCellRenderer renderer = this.renderer;
if (renderer == null) {
renderer = table.getTableHeader().getDefaultRenderer();
}
Component comp = renderer.getTableCellRendererComponent(table, getHeaderValue() == null || getHeaderValue().trim().isEmpty() ? " "
: getHeaderValue(), false, false, -1, -1);
int height = comp.getPreferredSize().height;
int width = 0;
for (ColumnGroup columnGroup : groups) {
width += columnGroup.getSize(table).width;
}
for (TableColumn tableColumn : columns) {
width += tableColumn.getWidth();
width += margin;
}
return new Dimension(width, height);
}
public void setColumnMargin(int margin) {
this.margin = margin;
for (ColumnGroup columnGroup : groups) {
columnGroup.setColumnMargin(margin);
}
}
}
GroupableTableHeader.java
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;
/**
* GroupableTableHeader
*
* @version 1.0 20.10.1998
* @author Nobuo Tamemasa
*/
@SuppressWarnings("serial")
public class GroupableTableHeader extends JTableHeader {
@SuppressWarnings("unused")
private static final String uiClassID = "GroupableTableHeaderUI";
protected List<ColumnGroup> columnGroups = new ArrayList<ColumnGroup>();
public GroupableTableHeader(TableColumnModel model) {
super(model);
setUI(new GroupableTableHeaderUI());
setReorderingAllowed(false);
// setDefaultRenderer(new MultiLineHeaderRenderer());
}
@Override
public void updateUI() {
setUI(new GroupableTableHeaderUI());
}
@Override
public void setReorderingAllowed(boolean b) {
super.setReorderingAllowed(false);
}
public void addColumnGroup(ColumnGroup g) {
columnGroups.add(g);
}
public List<ColumnGroup> getColumnGroups(TableColumn col) {
for (ColumnGroup group : columnGroups) {
List<ColumnGroup> groups = group.getColumnGroups(col);
if (!groups.isEmpty()) {
return groups;
}
}
return Collections.emptyList();
}
public void setColumnMargin() {
int columnMargin = getColumnModel().getColumnMargin();
for (ColumnGroup group : columnGroups) {
group.setColumnMargin(columnMargin);
}
}
}
GroupableTableHeaderUI.java
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.swing.JComponent;
import javax.swing.UIManager;
import javax.swing.plaf.basic.BasicTableHeaderUI;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;
public class GroupableTableHeaderUI extends BasicTableHeaderUI {
protected GroupableTableHeader getHeader() {
return (GroupableTableHeader) header;
}
@Override
public void paint(Graphics g, JComponent c) {
Rectangle clipBounds = g.getClipBounds();
if (header.getColumnModel().getColumnCount() == 0) {
return;
}
int column = 0;
Dimension size = header.getSize();
Rectangle cellRect = new Rectangle(0, 0, size.width, size.height);
Map<ColumnGroup, Rectangle> groupSizeMap = new HashMap<ColumnGroup, Rectangle>();
for (Enumeration<TableColumn> enumeration = header.getColumnModel().getColumns(); enumeration.hasMoreElements();) {
cellRect.height = size.height;
cellRect.y = 0;
TableColumn aColumn = enumeration.nextElement();
List<ColumnGroup> groups = getHeader().getColumnGroups(aColumn);
int groupHeight = 0;
for (ColumnGroup group : groups) {
Rectangle groupRect = groupSizeMap.get(group);
if (groupRect == null) {
groupRect = new Rectangle(cellRect);
Dimension d = group.getSize(header.getTable());
groupRect.width = d.width;
groupRect.height = d.height;
groupSizeMap.put(group, groupRect);
}
paintCell(g, groupRect, group);
groupHeight += groupRect.height;
cellRect.height = size.height - groupHeight;
cellRect.y = groupHeight;
}
cellRect.width = aColumn.getWidth();
if (cellRect.intersects(clipBounds)) {
paintCell(g, cellRect, column);
}
cellRect.x += cellRect.width;
column++;
}
}
private void paintCell(Graphics g, Rectangle cellRect, int columnIndex) {
TableColumn aColumn = header.getColumnModel().getColumn(columnIndex);
TableCellRenderer renderer = aColumn.getHeaderRenderer();
if (renderer == null) {
renderer = getHeader().getDefaultRenderer();
}
Component c = renderer.getTableCellRendererComponent(header.getTable(), aColumn.getHeaderValue(), false, false,
-1, columnIndex);
c.setBackground(UIManager.getColor("control"));
rendererPane.paintComponent(g, c, header, cellRect.x, cellRect.y, cellRect.width, cellRect.height, true);
}
private void paintCell(Graphics g, Rectangle cellRect, ColumnGroup cGroup) {
TableCellRenderer renderer = cGroup.getHeaderRenderer();
if (renderer == null) {
renderer = getHeader().getDefaultRenderer();
}
Component component = renderer.getTableCellRendererComponent(header.getTable(), cGroup.getHeaderValue(), false,
false, -1, -1);
rendererPane
.paintComponent(g, component, header, cellRect.x, cellRect.y, cellRect.width, cellRect.height, true);
}
private int getHeaderHeight() {
int headerHeight = 0;
TableColumnModel columnModel = header.getColumnModel();
for (int column = 0; column < columnModel.getColumnCount(); column++) {
TableColumn aColumn = columnModel.getColumn(column);
TableCellRenderer renderer = aColumn.getHeaderRenderer();
if (renderer == null) {
renderer = getHeader().getDefaultRenderer();
}
Component comp = renderer.getTableCellRendererComponent(header.getTable(), aColumn.getHeaderValue(), false,
false, -1, column);
int cHeight = comp.getPreferredSize().height;
List<ColumnGroup> groups = getHeader().getColumnGroups(aColumn);
for (ColumnGroup group : groups) {
cHeight += group.getSize(header.getTable()).height;
}
headerHeight = Math.max(headerHeight, cHeight);
}
return headerHeight;
}
@Override
public Dimension getPreferredSize(JComponent c) {
int width = 0;
for (Enumeration<TableColumn> enumeration = header.getColumnModel().getColumns(); enumeration.hasMoreElements();) {
TableColumn aColumn = enumeration.nextElement();
width += aColumn.getPreferredWidth();
}
return createHeaderSize(width);
}
private Dimension createHeaderSize(int width) {
TableColumnModel columnModel = header.getColumnModel();
width += columnModel.getColumnMargin() * columnModel.getColumnCount();
if (width > Integer.MAX_VALUE) {
width = Integer.MAX_VALUE;
}
return new Dimension(width, getHeaderHeight());
}
}