how to extend BooleanRenderer

Question

I'm trying to implement mouse hover effects for my JTable. (When the mouse goes over a table's row the row's background changes).

In order to do that, I extended the DefaultTableCellRenderer like this:

public class FileTableCellRenderer extends DefaultTableCellRenderer{

public FileTableCellRenderer() {
    setOpaque(true);        
}

public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
    FileTable fileTable = (FileTable)table;     

    Component c = super.getTableCellRendererComponent(fileTable, value, isSelected, hasFocus, row, column);

    if(!isSelected){
        if(row == fileTable.getCursorRow())
        {           
            c.setBackground(Color.pink);
            c.setForeground(Color.darkGray);
        }
        else
        {
            c.setBackground(Color.white);
            c.setForeground(Color.darkGray);
        }           
    }       

    this.setText(value.toString());

    return this;
}
}

I set the JTable's defaultRenderer, and it works. The problem is I have one column which is Boolean. before I set my renderer I had this cute checkbox as default renderer for it.

Now, it just shows "true" or "false".

On the other hand, if I leave the defualt BooleanRenderer for the Boolean column, it will not be highlighted with the whole row...

I also tried to extned the JTable.BooleanRenderer, but it seems to be protected, so I cannot even extend it.

How can I leave this checkbox of the BooleanRenderer, but change background color with the rest of the row?

Set your own renderer, and make what you want .. or you can have by composition a BooleanCellRenderer, first call BooleanCellRenderer#getTableCellRendererComponent and then with your implementation.. — nachokk, Sep 27 '13 at 19:11
please for why reson is there needed (unknow and probably buggy) BooleanRenderer, maybe I can't found any reason, or am I wrong .... — mKorbel, Sep 27 '13 at 19:13
it will not be highlighted with the whole row... == use prepareRenderer — mKorbel, Sep 27 '13 at 19:14

score 1 · Answer 1 · answered Sep 16 '20 at 00:24

This cannot be done using inheritance since BooleanRenderer is a non-public inner class of JTable. But you can use composition instead. E.g., create a wrapper class that will accept a TableCellRenderer ('parent') as a constructor argument. If you pass a BooleanRenderer from your table as a parent, calling its getTableCellRendererComponent() method will return a Checkbox component, so you'll be able to make any further adjustments to it (I use code from the question to set the background color):

import javax.swing.*;
import javax.swing.plaf.UIResource;
import javax.swing.table.TableCellRenderer;
import java.awt.*;

public class BooleanCellRenderer implements TableCellRenderer, UIResource {

    private final TableCellRenderer parent;

    public BooleanCellRenderer(TableCellRenderer parent) {
        this.parent = parent;
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        Component c = parent.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        FileTable fileTable = (FileTable) table;
        if (!isSelected) {
            if (row == fileTable.getCursorRow()) {
                c.setBackground(Color.pink);
                c.setForeground(Color.darkGray);
            } else {
                c.setBackground(Color.white);
                c.setForeground(Color.darkGray);
            }
        }
        return c;
    }
}

Then, in your main GUI class containing a JTable, take the table's default Boolean renderer and pass it to the wrapper:

FileTable fileTable = new FileTable();
fileTable.setDefaultRenderer(Boolean.class, new BooleanCellRenderer(fileTable.getDefaultRenderer(Boolean.class)));

You can leave the FileTableCellRenderer to render String cells:

FileTable fileTable = new FileTable();
fileTable.setDefaultRenderer(String.class, new FileTableCellRenderer());
fileTable.setDefaultRenderer(Boolean.class, new

how to extend BooleanRenderer

1 Answers1