Order of Events with JTable


M

MysteryMan

I downloaded the TableRenderDemo.java example found on the following
webpage:

http://java.sun.com/docs/books/tutorial/uiswing/components/table.html

I made a small change to the program that changes the contents of the
selection box based on what record number is selected (in order to test
functionality - code follows). I noticed some undesired behavior...

Namely, if I click on the table row outside of Sport column, the
combobox updates properly. If I click on the table row inside the Sport
column *first* the combobox fails to update (probably because it is
firing the dropdown events, etc before the update takes place.)

Is there a way to either a) prevent editing altogether on a JTable (the
easy solution) or b) make the combobox update FIRST if the user happens
to click in that space first?

(You can check the original code on the above website. My modified code
follows...)

/*
* TableRenderDemo.java is a 1.4 application that requires no other
files.
*/

import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import javax.swing.ListSelectionModel;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;

/**
* TableRenderDemo is just like TableDemo, except that it
* explicitly initializes column sizes and it uses a combo box
* as an editor for the Sport column.
*/
public class TableRenderDemo extends JPanel {
private boolean DEBUG = false;

public TableRenderDemo() {
super(new GridLayout(1,0));

final JTable table = new JTable(new MyTableModel());
table.setPreferredScrollableViewportSize(new Dimension(500,
70));
table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
ListSelectionModel rowSM = table.getSelectionModel();
rowSM.addListSelectionListener(new ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
//Ignore extra messages.
if (e.getValueIsAdjusting()) return;

ListSelectionModel lsm =
(ListSelectionModel)e.getSource();
if (lsm.isSelectionEmpty()) {
//no rows are selected
} else {
int selectedRow = lsm.getMinSelectionIndex
();
//selectedRow is selected
if (selectedRow == 2 || selectedRow == 4)
{
setUpSportColumn(table,
table.getColumnModel().getColumn(2), 1);
} else {
setUpSportColumn(table,
table.getColumnModel().getColumn(2), 0);
}
}
}
});

//Create the scroll pane and add the table to it.
JScrollPane scrollPane = new JScrollPane(table);

//Set up column sizes.
initColumnSizes(table);

//Fiddle with the Sport column's cell editors/renderers.
setUpSportColumn(table, table.getColumnModel().getColumn(2), 0);

//Add the scroll pane to this panel.
add(scrollPane);
}

/*
* This method picks good column sizes.
* If all column heads are wider than the column's cells'
* contents, then you can just use column.sizeWidthToFit().
*/
private void initColumnSizes(JTable table) {
MyTableModel model = (MyTableModel)table.getModel();
TableColumn column = null;
Component comp = null;
int headerWidth = 0;
int cellWidth = 0;
Object[] longValues = model.longValues;
TableCellRenderer headerRenderer =
table.getTableHeader().getDefaultRenderer();

for (int i = 0; i < 5; i++) {
column = table.getColumnModel().getColumn(i);

comp = headerRenderer.getTableCellRendererComponent(
null, column.getHeaderValue(),
false, false, 0, 0);
headerWidth = comp.getPreferredSize().width;

comp = table.getDefaultRenderer(model.getColumnClass(i)).
getTableCellRendererComponent(
table, longValues,
false, false, 0, i);
cellWidth = comp.getPreferredSize().width;

if (DEBUG) {
System.out.println("Initializing width of column "
+ i + ". "
+ "headerWidth = " + headerWidth
+ "; cellWidth = " + cellWidth);
}

//XXX: Before Swing 1.1 Beta 2, use setMinWidth instead.
column.setPreferredWidth(Math.max(headerWidth, cellWidth));
}
}

public void setUpSportColumn(JTable table,
TableColumn sportColumn, int
InfectionType) {
//Set up the editor for the sport cells.
if (InfectionType == 0 ) {
JComboBox comboBox = new JComboBox();
comboBox.addItem("Snowboarding");
comboBox.addItem("Rowing");
comboBox.addItem("Knitting");
comboBox.addItem("Speed reading");
comboBox.addItem("Pool");
comboBox.addItem("None of the above");
sportColumn.setCellEditor(new DefaultCellEditor
(comboBox));

//Set up tool tips for the sport cells.
DefaultTableCellRenderer renderer =
new DefaultTableCellRenderer();
renderer.setToolTipText("Click for combo box");
sportColumn.setCellRenderer(renderer);
} else {
JComboBox comboBox = new JComboBox();
comboBox.addItem("Snowboarding");
comboBox.addItem("Rowing");
comboBox.addItem("None of the above");
sportColumn.setCellEditor(new DefaultCellEditor
(comboBox));

//Set up tool tips for the sport cells.
DefaultTableCellRenderer renderer =
new DefaultTableCellRenderer();
renderer.setToolTipText("Click for combo box");
sportColumn.setCellRenderer(renderer);
}
}

class MyTableModel extends AbstractTableModel {
private String[] columnNames = {"First Name",
"Last Name",
"Sport",
"# of Years",
"Vegetarian"};
private Object[][] data = {
{"Mary", "Campione",
"Snowboarding", new Integer(5), new Boolean(false)},
{"Alison", "Huml",
"Rowing", new Integer(3), new Boolean(true)},
{"Kathy", "Walrath",
"Knitting", new Integer(2), new Boolean(false)},
{"Sharon", "Zakhour",
"Speed reading", new Integer(20), new Boolean(true)},
{"Philip", "Milne",
"Pool", new Integer(10), new Boolean(false)}
};

public final Object[] longValues = {"Sharon", "Campione",
"None of the above",
new Integer(20),
Boolean.TRUE};

public int getColumnCount() {
return columnNames.length;
}

public int getRowCount() {
return data.length;
}

public String getColumnName(int col) {
return columnNames[col];
}

public Object getValueAt(int row, int col) {
return data[row][col];
}

/*
* JTable uses this method to determine the default renderer/
* editor for each cell. If we didn't implement this method,
* then the last column would contain text ("true"/"false"),
* rather than a check box.
*/
public Class getColumnClass(int c) {
return getValueAt(0, c).getClass();
}

/*
* Don't need to implement this method unless your table's
* editable.
*/
public boolean isCellEditable(int row, int col) {
//Note that the data/cell address is constant,
//no matter where the cell appears onscreen.
if (col < 2) {
return false;
} else {
return true;
}
}

/*
* Don't need to implement this method unless your table's
* data can change.
*/
public void setValueAt(Object value, int row, int col) {
if (DEBUG) {
System.out.println("Setting value at " + row + "," + col
+ " to " + value
+ " (an instance of "
+ value.getClass() + ")");
}

data[row][col] = value;
fireTableCellUpdated(row, col);

if (DEBUG) {
System.out.println("New value of data:");
printDebugData();
}
}

private void printDebugData() {
int numRows = getRowCount();
int numCols = getColumnCount();

for (int i=0; i < numRows; i++) {
System.out.print(" row " + i + ":");
for (int j=0; j < numCols; j++) {
System.out.print(" " + data[j]);
}
System.out.println();
}
System.out.println("--------------------------");
}
}

/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);

//Create and set up the window.
JFrame frame = new JFrame("TableRenderDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//Create and set up the content pane.
TableRenderDemo newContentPane = new TableRenderDemo();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);

//Display the window.
frame.pack();
frame.setVisible(true);
}

public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
 
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