I am currently working on a JComboBox component where I want to have a JTable inside of a ComboBox for a drop down selection. I have extended the ListCellRenderer and I have the table inside of the popup.
I want to present it two different ways. The first as a label of a bound column of the selected row when the popup is not visible. The second is to show the table with a JScrollPane when the popup is visible.
Unfortunately, When I do this the popup is being shrunk to the row height of the list which only leaves room for the columns of the table.
If I just use the scrollpane I can see the full table but then when the popup is not visible I see the table inside the combobox which is not what I want.
How can I set the height such that the table can fit while still being able to show the label only when the popup is not visible?
Below is a minimal example that compiles and runs:
import java.awt.Color;
import java.awt.Component;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.ListCellRenderer;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.table.DefaultTableModel;
public class TableComboBoxMain {
public static void main(String[] args) {
JTableComboBox<Employee> combo = new JTableComboBox<>();
combo.addItem(new Employee("April",3));
//combo.setMaximumRowCount(10);
combo.setRenderer(new TableListCellRenderer(combo));
JFrame frame = new JFrame("Test Table Combo Box");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(combo);
frame.pack();
frame.setVisible(true);
}
public static class Employee{
String name;
int nr;
public Employee(String name, int number ){
this.name =name;
this.nr = number;
}
}
public static class JTableComboBox<E> extends JComboBox<E> implements ListSelectionListener{
@Override
public void valueChanged(ListSelectionEvent e) {System.out.println("Row selected"+e.getFirstIndex());
this.setSelectedIndex(e.getFirstIndex());
}
}
public static class TableListCellRenderer extends JScrollPane implements ListCellRenderer{
JTable table;
JTableComboBox combo;
boolean mouseListenerAdded;
public TableListCellRenderer(JTableComboBox combo){
this.combo=combo;
DefaultTableModel model = new DefaultTableModel();
String[] cols1 = new String[]{"1","2","3","4"};
String[] cols2 = new String[]{"Mark","John","April","Mary"};
model.addColumn("Nr", cols1);model.addColumn("Name",cols2);
table = new JTable(model);table.setShowGrid(true);table.setGridColor(Color.gray);
this.getViewport().add(table);
}
@Override
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
if(!mouseListenerAdded){
list.addMouseListener(this.getListener());
mouseListenerAdded = true;
}//If this is uncommented then the BasicComboPopup size is always no more than 1 row?!!
if(!combo.isPopupVisible()){
Employee emp = (Employee) value;
return new JLabel(emp.name);
}else
return this;
}
public MouseAdapter getListener(){
MouseAdapter adapter = new MouseAdapter(){
@Override
public void mousePressed(MouseEvent e) {
if(combo.isPopupVisible()){
System.out.println("MouseClicked over list");
int row = table.rowAtPoint(e.getPoint());
if(row>0){
table.setRowSelectionInterval(row-1, row-1);
ListDataEvent event = new ListDataEvent(combo,ListDataEvent.CONTENTS_CHANGED,row-1,row-1);
combo.contentsChanged(event);
}
}
}
};
return adapter;
}
}
}
So I found a solution to the problem. I am not finished yet because there are a few interactions I still want to have:
I wanted to post the solution in case anyone else wants a starting point example. I will update my answer as I solve these additional issues.
Below is the test class:
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.ScrollPaneConstants;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.plaf.basic.BasicComboBoxUI;
import javax.swing.plaf.basic.BasicComboPopup;
import javax.swing.plaf.basic.ComboPopup;
import javax.swing.table.DefaultTableModel;
public class TableComboBoxMain {
public static void main(String[] args) {
JTableComboBox<String> combo = new JTableComboBox<>();
combo.addItem("");
BasicComboBoxUI ui = new BasicComboBoxUI(){
@Override
protected ComboPopup createPopup() {
return new BasicComboPopup( comboBox ){
@Override
protected int getPopupHeightForRowCount(int maxRowCount) {
return 100;
}
@Override
protected JScrollPane createScroller() {
JScrollPane sp = new JScrollPane( list,
ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED );
sp.getHorizontalScrollBar().setFocusable( false );
return sp;
}
};
}
};
combo.setUI(ui);
combo.setRenderer(new TableListCellRenderer(combo));
JFrame frame = new JFrame("Test Table Combo Box");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(combo);
frame.pack();
frame.setVisible(true);
}
public static class Employee{
String name;
int nr;
public Employee(String name, int number ){
this.name =name;
this.nr = number;
}
}
public static class JTableComboBox<E> extends JComboBox<E> implements ListSelectionListener{
@Override
public void valueChanged(ListSelectionEvent e) {
System.out.println("Row selected"+e.getFirstIndex());
this.setSelectedIndex(e.getFirstIndex());
}
}
public static class TableListCellRenderer extends DefaultListCellRenderer{
JTable table;
JTableComboBox combo;
JPanel renderer = new JPanel();
JPanel colHeader = new JPanel();
JScrollPane scroll = new JScrollPane();
boolean mouseListenerAdded;
public TableListCellRenderer(JTableComboBox combo){
this.combo=combo;
DefaultTableModel model = new DefaultTableModel();
String[] cols1 = new String[]{"1","2","3","4","5","6"};
String[] cols2 = new String[]{"Mark","John","April","Mary","Joe","Jack"};
model.addColumn("Nr", cols1);model.addColumn("Name",cols2);
table = new JTable(model);
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
colHeader.add(table.getTableHeader());
renderer.setLayout(new BorderLayout());
renderer.add(colHeader, BorderLayout.NORTH);
renderer.add(table,BorderLayout.CENTER);
scroll.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER);
scroll.getViewport().add(table);
}
@Override
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
list.setFixedCellHeight(table.getRowHeight()*(table.getRowCount()+1)+10);
list.setFixedCellWidth(table.getPreferredSize().width);
JLabel label = (JLabel) super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
if(!mouseListenerAdded){
list.addMouseListener(this.getListener());
mouseListenerAdded = true;
}
if(!combo.isPopupVisible()){
label.setText("Select...");
if(table.getSelectedRowCount()>0)
label.setText(""+table.getModel().getValueAt(table.getSelectedRow(),1));
return label;
}
return scroll;
}
public MouseAdapter getListener(){
MouseAdapter adapter = new MouseAdapter(){
@Override
public void mousePressed(MouseEvent e) {
if(combo.isPopupVisible()){
System.out.println("MouseClicked over list");
int row = table.rowAtPoint(e.getPoint());
if(row>0){
table.setRowSelectionInterval(row-1, row-1);
ListDataEvent event = new ListDataEvent(combo,ListDataEvent.CONTENTS_CHANGED,row-1,row-1);
combo.contentsChanged(event);
}
}
}
};
return adapter;
}
}
}
The key parts of the solution is that in order to have the table and the features of a table that you would want in a popup is you need to override the UI. Specifically you need to override the createPopup on BasicComboBoxUI, getPopupHeightForRowCount and createScroller on BasicComboPopup. Lastly, when implementing getListCellRenderingComponent you have set a fixed height and width that matches the tables preferred height and width. This will allow the main scroller of the popup to act as the scrollpane for the table.