button | Tech Tips & Tricks

Swing components in Java are very flexible. You can change the table header of a JTable to become a JButton to display the headers as clickable. The class PushtableTableHeader does just that. See the code below.

public class PushableTableHeader extends JPanel {
    public PushableTableHeader(TableColumn column, JTableHeader header) {
        setLayout(new BorderLayout());
        ButtonHeaderRenderer renderer = new ButtonHeaderRenderer();
        column.setHeaderRenderer(renderer);
        header.addMouseListener(new HeaderListener(header, renderer));
    }
    public class HeaderListener extends MouseAdapter {
        JTableHeader header;
        ButtonHeaderRenderer renderer;
        HeaderListener(JTableHeader header, ButtonHeaderRenderer renderer) {
            this.header   = header;
            this.renderer = renderer;
        }
        @Override
        public void mousePressed(MouseEvent e) {
            int col = header.columnAtPoint(e.getPoint());
            renderer.setPressedColumn(col);
            header.repaint();
        }
        @Override
        public void mouseReleased(MouseEvent e) {
            int col = header.columnAtPoint(e.getPoint());
            renderer.setPressedColumn(-1);
            header.repaint();
        }
    }
    class ButtonHeaderRenderer extends JButton implements TableCellRenderer {
        int pushedColumn;
        public ButtonHeaderRenderer() {
            pushedColumn   = -1;
            setMargin(new Insets(0,0,0,0));
        }
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            setText((value ==null) ? "" : value.toString());
            boolean isPressed = (column == pushedColumn);
            getModel().setPressed(isPressed);
            getModel().setArmed(isPressed);
            return this;
        }
        public void setPressedColumn(int col) {
            pushedColumn = col;
        }
    }
}

public class PushableTableHeader extends JPanel {

public PushableTableHeader(TableColumn column, JTableHeader header) {

setLayout(new BorderLayout());

ButtonHeaderRenderer renderer = new ButtonHeaderRenderer();

column.setHeaderRenderer(renderer);

header.addMouseListener(new HeaderListener(header, renderer));

}

public class HeaderListener extends MouseAdapter {

JTableHeader header;

ButtonHeaderRenderer renderer;

HeaderListener(JTableHeader header, ButtonHeaderRenderer renderer) {

this.header = header;

this.renderer = renderer;

}

@Override

public void mousePressed(MouseEvent e) {

int col = header.columnAtPoint(e.getPoint());

renderer.setPressedColumn(col);

header.repaint();

}

@Override

public void mouseReleased(MouseEvent e) {

int col = header.columnAtPoint(e.getPoint());

renderer.setPressedColumn(-1);

header.repaint();

}

class ButtonHeaderRenderer extends JButton implements TableCellRenderer {

int pushedColumn;

public ButtonHeaderRenderer() {

pushedColumn = -1;

setMargin(new Insets(0,0,0,0));

}

@Override

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

setText((value ==null) ? "" : value.toString());

boolean isPressed = (column == pushedColumn);

getModel().setPressed(isPressed);

getModel().setArmed(isPressed);

return this;

}

public void setPressedColumn(int col) {

pushedColumn = col;

}

To use the class, you can do it like this.

new PushableTableHeader(jTable1.getColumn("MY_COLUMN_NAME"), jTable1.getTableHeader());

1	new PushableTableHeader(jTable1.getColumn("MY_COLUMN_NAME"), jTable1.getTableHeader());

I purposely placed this in a class so that I could isolate only table columns that need to have a pushable button as its header.

These two functions for getting and setting a radio button using Javascript regardless of how many radio buttons there are in the group is shorter and simpler than the functions I posted before. The functions below came from this site.

// return the value of the radio button that is checked
// return an empty string if none are checked, or
// there are no radio buttons
function getCheckedValue(radioObj) {
  if (!radioObj) return "";
  var radioLength = radioObj.length;
  if (radioLength == undefined) {
    if (radioObj.checked) return radioObj.value;
    else return "";
  }
  for (var i=0; i<radioLength; i++) {
    if (radioObj[i].checked) {
      radioObj[i].value;
      break;
    }
  }
  return "";
}
// set the radio button with the given value as being checked
// do nothing if there are no radio buttons
// if the given value does not exist, all the radio buttons
// are reset to unchecked
function setCheckedValue(radioObj, newValue) {
  if (!radioObj) return;
  var radioLength = radioObj.length;
  if (radioLength == undefined) {
    radioObj.checked = (radioObj.value == newValue.toString());
    return;
  }
  for (var i=0; i<radioLength; i++) {
    radioObj[i].checked = false;
    if (radioObj[i].value == newValue.toString()) {
      [i].checked = true;
    }
  }
}

// return the value of the radio button that is checked

// return an empty string if none are checked, or

// there are no radio buttons

function getCheckedValue(radioObj) {

if (!radioObj) return "";

var radioLength = radioObj.length;

if (radioLength == undefined) {

if (radioObj.checked) return radioObj.value;

else return "";

}

for (var i=0; i<radioLength; i++) {

if (radioObj[i].checked) {

radioObj[i].value;

break;

}

return "";

}

// set the radio button with the given value as being checked

// do nothing if there are no radio buttons

// if the given value does not exist, all the radio buttons

// are reset to unchecked

function setCheckedValue(radioObj, newValue) {

if (!radioObj) return;

var radioLength = radioObj.length;

if (radioLength == undefined) {

radioObj.checked = (radioObj.value == newValue.toString());

return;

}

for (var i=0; i<radioLength; i++) {

radioObj[i].checked = false;

if (radioObj[i].value == newValue.toString()) {

[i].checked = true;

}

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Tag: button

Create Pushable Button Table Headers In JTable

Get Or Set Radio Button Using Javascript