JTable dynamic JCheckBox needs 1 click to uncheck, but 2 clicks to check

Question

I am fairly new to java, so please excuse me for any foolish mistakes i make ...

I have a JTable of 2 columns in which the 2nd column can have 4 types :

a column in which values cannot be changed
a column which can contain any text string
a column which contains JComboBoxes
a column which contains JCheckBoxes

The column types are dynamically since they depend on the data being received.

All types work fine, except the JCheckBox. When I replace the JCheckBox with a JComboBox with 2 choices, then it works fine. So i guess there is a problem in the code for the JCheckBox.

The problem is :

when the JCheckBox is checked, then I need only 1 click to uncheck it
however when the JCheckBox is unchecked, then I need to click it twice (not doubleclick) to check it

EDIT

An example project (as small as i can make it) :

    import java.awt.Component;
    import javax.swing.*;
    import javax.swing.event.*;
    import javax.swing.table.*;

    public class frmCheck extends JApplet
    {
        JTable mgrdData;
        DefaultTableModel mtableModel;

        public void init()
        {
            mtableModel = new DefaultTableModel();
            mtableModel.setColumnCount(2);
            mtableModel.setRowCount(4);
            mgrdData = new JTable(mtableModel);
            mgrdData.getSelectionModel().addListSelectionListener(new RowListener());
            add(mgrdData);
            for (int i=1;i



The html page which i use to view the Applet is :


  
    
  



To make it an executable (application) you can add the following main() function to it (above the init() function, and below the declaration of mtableModel)

        public static void main(String[] args) {
        frmCheck myApplet = new frmCheck(); // define applet of interest
        Frame myFrame = new Frame("Applet Holder"); // create frame with title

        // Call applet's init method (since Java App does not
        // call it as a browser automatically does)
        myApplet.init();    

        // add applet to the frame
        myFrame.add(myApplet, BorderLayout.CENTER);
        myFrame.pack(); // set window to appropriate size (for its elements)
        myFrame.setVisible(true); // usual step to make frame visible

      } 


When you click on an unchecked checkbox, then the console shows :

isSelected = true
Sent 0


after that the checkbox is still unchecked
when i click the checkbox again (thus for a second time), then the console shows :

isSelected = false
Sent 1


the checkbox flashes as checked for a short time, and then becomes unchecked again
when i then click the checkbox again (thus for a third time), then it behaves like being clicked for the first time

I want the checkbox to :
- send 1 when unchecked and clicked
- Send 0 when checked and clicked

The real project is a bit more complex : by checking the JCheckBox I send a message to a device, which answers with its current state, which is processed and shown as a checked JCheckBox.
The processing works fine as when I change the state in the device via another channel, then the JCheckBox shows the current state perfectly

I would like the JCheckBox to respond to 1 click :


when it's checked and I click it then it should send "REG SCH 4 = 0"
when it's unchecked and I click it then it should send "REG SCH 4 = 1"


Ok here is the code i have so far :

The JTable is created as follows :

JTable mgrdData;
DefaultTableModel mtableModel;
mtableModel = new DefaultTableModel(null,new String[0]);
mgrdData = new JTable(mtableModel);
mgrdData.getSelectionModel().addListSelectionListener(new RowListener());
mgrdData.setFillsViewportHeight(true);
String[] strHeader = {"Naam","Waarde"};
mtableModel.setColumnIdentifiers(strHeader);


The columns are configured as follows :

        addReadOnly(0);
//          addCombo(1,new String[]{"UIT","AAN"}); //this works fine
        addCheck(1);


Column 0 is readonly, and column 1 has 2 possible values
where addCombo(1,new String[]{"UIT","AAN"}); perfectly works

The functions addReadOnly and addCombo and addCheck are as follows :

private void addReadOnly(int intCol)
{
    JTextField txtField = new JTextField();
    txtField.setEditable(false);
    DefaultCellEditor cellEditor = new DefaultCellEditor(txtField);
    mgrdData.getColumnModel().getColumn(intCol).setCellEditor(cellEditor);
}

private void addCombo(int intCol,final String[] strItems)
{
    //add combobox
    mgrdData.getColumnModel().getColumn(intCol).setCellRenderer(new TableCellRenderer()
    {
        public Component getTableCellRendererComponent(JTable table,Object value,boolean isSelected,boolean isFocused,int row,int col)
        {
            JComboBox rendererComponent = new JComboBox(strItems);
            if (value!=null) rendererComponent.setSelectedItem(value.toString());
            return rendererComponent;
        }
    });
    DefaultCellEditor cellEditor = new DefaultCellEditor(new JComboBox(strItems));
    cellEditor.setClickCountToStart(1);
    cellEditor.addCellEditorListener(new CellEditorListener()
    {
        private boolean blnChanged=false;
        public void editingCanceled(ChangeEvent e) {}
        public void editingStopped(ChangeEvent e)
        {
            if (blnChanged==true)
            {
                JComboBox comboBox = (JComboBox)((DefaultCellEditor)e.getSource()).getComponent(); 
                sendVal(String.valueOf(comboBox.getSelectedIndex()));
                blnChanged = false;
            } else
            {
                blnChanged = true; 
            } 
        }
    });
    mgrdData.getColumnModel().getColumn(intCol).setCellEditor(cellEditor);
}

private void addCheck(int intCol)
{
    //add checkbox
    mgrdData.getColumnModel().getColumn(intCol).setCellRenderer(new TableCellRenderer()
    {
        public Component getTableCellRendererComponent(JTable table,Object value,boolean isSelected,boolean isFocused,int row,int col)
        {
            JCheckBox rendererComponent = new JCheckBox();
            String strVal="";
            if (value!=null) strVal = value.toString();
//              if (strVal.equals("AAN"))
            if (strVal.equals("1"))
            {
                rendererComponent.setSelected(true);
            } else
            {
                rendererComponent.setSelected(false);
            }
            return rendererComponent;
        }
    });
    DefaultCellEditor cellEditor = new DefaultCellEditor(new JCheckBox());
    cellEditor.setClickCountToStart(1);
    cellEditor.addCellEditorListener(new CellEditorListener()
    {
        public void editingCanceled(ChangeEvent e) {}
        public void editingStopped(ChangeEvent e)
        {
            JCheckBox checkBox = (JCheckBox)((DefaultCellEditor)e.getSource()).getComponent();
            System.out.println("isSelected = " + checkBox.isSelected());
            if (checkBox.isSelected())
            {
                sendVal("0");
                System.out.println("Sent 0");
            } else
            {
                sendVal("1");
                System.out.println("Sent 1");
            }
        }
    });
    mgrdData.getColumnModel().getColumn(intCol).setCellEditor(cellEditor);
}


Test results after 3 times clicking :

JCheckBox is checked, result after 1 click :

isSelected = true
Sent : REG SCH 4 = 0
Sent 0


After this the JCheckBox is unchecked

JCheckBox is unchecked, result after 1 click :

isSelected = true
Sent : REG SCH 4 = 0
Sent 0


After this the JCheckBox is still unchecked

JCheckBox is unchecked but clicked once already, result after the second click :

isSelected = false
Sent : REG SCH 4 = 1
Sent 1


After this the JCheckBox is checked

I search and found solution for when you always needed 2 clicks, or solutions with fixed checkboxes instead of dynamically, but not a case like mine ....

could anyone please shed a light ?

Alfergon · Accepted Answer

Answer

Problem was that you were treating the checkbox value as a String when it's a boolean.

Working code is the following:

Boolean val = new Boolean(false);
if (value != null){
    val = (Boolean) value;
}
if (val.booleanValue()) {
    rendererComponent.setSelected(true);
}else{
     rendererComponent.setSelected(false);
}
return rendererComponent;

Old answer

I'm still looking at it, but I think the problem might be due to the fact that the JCheckBox is selected or not depending on:

if (strVal.equals("AAN"))
        {
            rendererComponent.setSelected(true);
        } else
        {
            rendererComponent.setSelected(false);
        }

Isn't "AAN" a value for the dropbox instead than for the checkbutton?

An also, you're creating a new JCheckBox each time.

Maybe a SSCCE could be useful.

JTable dynamic JCheckBox needs 1 click to uncheck, but 2 clicks to check

EDIT

Answers (2)

Answer

Old answer

Related Questions