How to reset JComboBox in JTable to first JComboBox value

Question

I am working on code in Java Swing. I created a JComboBox in JTable. It works:). But as soon as I select a value and press the save or cancel button, it should reset to set the default value (1st value in the combo box). I tried many ways like combobox.setSelectedIndex(0) . This does not work. Code:

 String[] manTimeHr = { "00","01", "02", "03","04","05","06","07","08","09","10","11","12","13","14","15","16","17","18","19","20","21","22","23"}; String[] manTimeMin = {"00","01", "02", "03","04","05","06","07","08","09","10","11","12","13", "14", "15","16","17","18","19","20","21","22","23","24","25", "26", "27","28","29","30","31","32","33","34","35","36","37","38","39","40","41","42","43","44","45","46","47","48","49","50","51","52","53","54","55","56","57","58","59"}; String[][] data = {{"-select-","-select-"}}; String[] cols = {"Hrs","Mins"}; String[][] data1 = {{"-select-","-select-"}}; String[] cols1 = {"Hrs","Mins"}; JLabel manTimeStart = new JLabel("Start From",JLabel.LEFT); STimeTbl = new JTable(data,cols); hrsColumn=STimeTbl.getColumnModel().getColumn(0); minsColumn=STimeTbl.getColumnModel().getColumn(1); manSiteStimeHrCBx = new JComboBox(manTimeHr); manSiteStimeHrCBx.setSelectedIndex(0); hrsColumn.setCellEditor(new DefaultCellEditor(manSiteStimeHrCBx)); manSiteStimeMinCBx = new JComboBox(manTimeMin); manSiteStimeMinCBx.setSelectedIndex(0); minsColumn.setCellEditor(new DefaultCellEditor(manSiteStimeMinCBx)); JLabel manTimeEnd = new JLabel("End To",JLabel.LEFT); ETimeTbl = new JTable(data1,cols1); hrsColumn1=ETimeTbl.getColumnModel().getColumn(0); minsColumn1=ETimeTbl.getColumnModel().getColumn(1); manSiteEtimeHrCBx = new JComboBox(manTimeHr); manSiteEtimeHrCBx.setSelectedIndex(0); hrsColumn1.setCellEditor(new DefaultCellEditor(manSiteEtimeHrCBx)); manSiteEtimeMinCBx = new JComboBox(manTimeMin); manSiteEtimeMinCBx.setSelectedIndex(0); minsColumn1.setCellEditor(new DefaultCellEditor(manSiteEtimeMinCBx)); . . . . if("Save".equals(e.getActionCommand())) { try{ mSHr = Integer.parseInt((String)manSiteStimeHrCBx.getSelectedItem()); mEHr=Integer.parseInt((String)manSiteEtimeHrCBx.getSelectedItem()); mSMin=Integer.parseInt((String)manSiteStimeMinCBx.getSelectedItem()); mEMin=Integer.parseInt((String)manServEtimeMinCBx.getSelectedItem()); }catch (Exception en){ System.out.println("Main Exception : "+ en); return; } if(validateBlockTime(mSHr,mEHr,mSMin,mEMin) != true) { System.out.println("Enter valid Time"); return; } manSiteStimeHrCBx.setSelectedIndex(0); manSiteStimeMinCBx.setSelectedIndex(0); manSiteEtimeHrCBx.setSelectedIndex(0); manSiteEtimeMinCBx.setSelectedIndex(0); . . . private static boolean validateBlockTime(int val3, int val4, int val5, int val6){ if(val4 > val3) return true; else if((val4 == val3) && (val6 > val5)) return true; else return false; } 

Answer 1

• JTable tutorial contains description of Combo Box as editor

• all data is stored in XxxTableModel

• all changes to the JTable view are described in the Concept: Editors and Renders

• then you should know that in XxxTableModel only the String value is stored (either Double or Long or Integer or Icon ) depends on the value stored in ComboBoxModel) for Combo Box as an editor

• result

quick code (sorry, I'm so lazy) based on the tutorial code

 import java.awt.BorderLayout; import java.awt.event.ActionEvent; 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 java.awt.Component; import java.awt.Dimension; import java.awt.event.ActionListener; import javax.swing.JButton; public class TableRenderDemo extends JPanel { private static final long serialVersionUID = 1L; private boolean DEBUG = false; public TableRenderDemo() { super(new BorderLayout(5, 5)); final JTable table = new JTable(new MyTableModel()); table.setRowHeight(18); table.setPreferredScrollableViewportSize(new Dimension(500, 70)); table.setFillsViewportHeight(true); table.setPreferredScrollableViewportSize(table.getPreferredSize()); JScrollPane scrollPane = new JScrollPane(table); initColumnSizes(table); setUpSportColumn(table, table.getColumnModel().getColumn(2)); add(scrollPane); JButton resetButton = new JButton("Reset to default"); resetButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { for (int i = 0; i < table.getRowCount(); i++) { table.getModel().setValueAt("None of the above", i, 2); } } }); add(resetButton, BorderLayout.SOUTH); } 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[i], false, false, 0, i); cellWidth = comp.getPreferredSize().width; if (DEBUG) { System.out.println("Initializing width of column " + i + ". " + "headerWidth = " + headerWidth + "; cellWidth = " + cellWidth); } column.setPreferredWidth(Math.max(headerWidth, cellWidth)); } } private void setUpSportColumn(JTable table, TableColumn sportColumn) { 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)); DefaultTableCellRenderer renderer = new DefaultTableCellRenderer(); renderer.setToolTipText("Click for combo box"); sportColumn.setCellRenderer(renderer); } private class MyTableModel extends AbstractTableModel { private static final long serialVersionUID = 1L; private String[] columnNames = {"First Name", "Last Name", "Sport", "# of Years", "Vegetarian"}; private Object[][] data = { {"Kathy", "Smith", "Snowboarding", new Integer(5), false}, {"John", "Doe", "Rowing", new Integer(3), true}, {"Sue", "Black", "Knitting", new Integer(2), false}, {"Jane", "White", "Speed reading", new Integer(20), true}, {"Joe", "Brown", "Pool", new Integer(10), false} }; public final Object[] longValues = {"Jane", "Kathy", "None of the above", new Integer(20), Boolean.TRUE}; public int getColumnCount() { return columnNames.length; } public int getRowCount() { return data.length; } @Override public String getColumnName(int col) { return columnNames[col]; } public Object getValueAt(int row, int col) { return data[row][col]; } @Override public Class<?> getColumnClass(int c) { return getValueAt(0, c).getClass(); } @Override public boolean isCellEditable(int row, int col) { if (col < 2) { return false; } else { return true; } } @Override public void setValueAt(Object value, int row, int col) { data[row][col] = value; fireTableCellUpdated(row, col); System.out.println(getValueAt(row, col)); } } private static void createAndShowGUI() { JFrame frame = new JFrame("TableRenderDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); TableRenderDemo newContentPane = new TableRenderDemo(); newContentPane.setOpaque(true); //content panes must be opaque frame.setContentPane(newContentPane); frame.pack(); frame.setVisible(true); } public static void main(String[] args) { javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } } 

output from AbstractTableModel , line of code 135th.

 run: None of the above None of the above None of the above None of the above None of the above BUILD SUCCESSFUL (total time: 37 seconds)