I’ve a requirement where, based on the content of a HashMap<String, String>, I’ve to add/remove columns from my table. While I’m able to add/remove columns, but my problem is that for some reason when I create new columns, the values are not getting set in the respective columns. I’m unable to figure out why.
Posting an SSCCE for your reference. Can you please tell me what am I doing wrong?
import java.util.HashMap;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;
public class TableTest extends javax.swing.JFrame {
/**
* Creates new form TableTest
*/
public TableTest() {
initComponents();
}
private void resetTable(){
TableColumnModel tableColumnModel = infoTable.getColumnModel();
DefaultTableModel tableModel = (DefaultTableModel) infoTable.getModel();
JTableHeader tableHeader = infoTable.getTableHeader();
tableColumnModel.getColumn(0).setHeaderValue("");
for(int columnIndex = 0; columnIndex < tableColumnModel.getColumnCount(); columnIndex++){
if(columnIndex > 3){
infoTable.removeColumn(tableColumnModel.getColumn(columnIndex));
}else{
tableModel.setValueAt("", 0, columnIndex);
tableModel.setValueAt("", 1, columnIndex);
}
}
tableHeader.repaint();
infoTable.revalidate();
infoTable.repaint();
}
private void createTable(HashMap<String, String> parameterMap){
resetTable();
TableColumnModel tableColumnModel = infoTable.getColumnModel();
DefaultTableModel tableModel = (DefaultTableModel) infoTable.getModel();
if(!parameterMap.isEmpty()){
int columnCount = 1;
for (String key : parameterMap.keySet()) {
if(columnCount >= tableColumnModel.getColumnCount()){
tableModel.addColumn("");
tableColumnModel.addColumn(new TableColumn());
}
columnCount++;
}
}
infoTable.revalidate();
infoTable.repaint();
}
private void updateInformationTable(HashMap<String, String> parameterMap){
createTable(parameterMap);
TableColumnModel tableColumnModel = infoTable.getColumnModel();
DefaultTableModel tableModel = (DefaultTableModel) infoTable.getModel();
JTableHeader tableHeader = infoTable.getTableHeader();
if(!parameterMap.isEmpty()){
tableColumnModel.getColumn(0).setHeaderValue(parameterMap.get("timer"));
int columnCount = 1;
for (String key : parameterMap.keySet()) {
tableModel.setValueAt((key.contains("unknown") ? "" : key), 0, columnCount);
tableModel.setValueAt(parameterMap.get(key), 1, columnCount);
columnCount++;
}
}
tableHeader.repaint();
infoTable.revalidate();
infoTable.repaint();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
jScrollPane1 = new javax.swing.JScrollPane();
infoTable = new javax.swing.JTable();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
infoTable.setModel(new javax.swing.table.DefaultTableModel(
new Object [][] {
{null, null, null, null},
{null, null, null, null},
},
new String [] {
"Title 1", "", "", ""
}
));
infoTable.setAutoscrolls(false);
infoTable.setShowHorizontalLines(false);
infoTable.setShowVerticalLines(false);
infoTable.setAutoCreateColumnsFromModel(false);
jScrollPane1.setViewportView(infoTable);
jButton1.setText("3 Columns");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setText("5 Columns");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addComponent(jButton1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 577, Short.MAX_VALUE)
.addComponent(jButton2))
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 739, Short.MAX_VALUE))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap(243, Short.MAX_VALUE)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2))
.addContainerGap())
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 234, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(0, 25, Short.MAX_VALUE)))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
HashMap<String, String> map = new HashMap<String, String>();
map.put("param1", "value1");
map.put("param2", "value2");
map.put("param3", "value3");
updateInformationTable(map);
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
HashMap<String, String> map = new HashMap<String, String>();
map.put("param1", "value1");
map.put("param2", "value2");
map.put("param3", "value3");
map.put("param4", "value4");
map.put("param5", "value5");
updateInformationTable(map);
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/*
* Set the Nimbus look and feel
*/
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/*
* If Nimbus (introduced in Java SE 6) is not available, stay with the
* default look and feel. For details see
* http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
javax.swing.UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel" /*
* UIManager.getSystemLookAndFeelClassName()
*/);
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(TableTest.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(TableTest.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(TableTest.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(TableTest.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/*
* Create and display the form
*/
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new TableTest().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JTable infoTable;
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JPanel jPanel1;
private javax.swing.JScrollPane jScrollPane1;
// End of variables declaration
}
That’s a lot of code to update a table. Try updating the model. Table will re-render itself. I had to change one further line:
infoTable.setAutoCreateColumnsFromModel(true);
And, Hashmap is not a good fit for the model data. How do I easily get the value at say row 3, column 2 from a HashMap?