Table header background is never restored after hover when the renderer background is null

[dar-dev]

The table header background is never restored after hover when the label renderer is opaque.

Here's a demo video:

tableheader_hover.mp4

Cheers,

Dar

--

[DevCharly]

... when the label renderer is opaque.

Sorry, but I'm not sure what you mean.
Is the renderer's background color null?

Could you please extend following test case to demonstrate the issue? Thanks.

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import com.formdev.flatlaf.FlatLightLaf;

public class TableHeaderTest
{
	public static void main( String[] args ) {
		SwingUtilities.invokeLater( () -> {
			FlatLightLaf.setup();

			JTable table = new JTable( new DefaultTableModel( 3, 3 ) );
			JScrollPane scrollPane = new JScrollPane( table );

			JFrame frame = new JFrame( "Test" );
			frame.setDefaultCloseOperation( WindowConstants.DISPOSE_ON_CLOSE );
			frame.add( scrollPane );

			frame.setSize( 400, 300 );
			frame.setVisible( true );
		} );
	}
}

[dar-dev]

Yep sorry, I made a mistake in the report. The case is when the label renderer has null background.

Here's the test case to replicate:

import java.awt.*;

import javax.swing.*;
import javax.swing.table.*;

import com.formdev.flatlaf.*;

public class TableHeaderTest
{
	public static void main( String[] args ) {
		SwingUtilities.invokeLater( () -> {
			FlatLightLaf.setup();

			JTable table = new JTable( new DefaultTableModel( 3, 3 ) );
			JScrollPane scrollPane = new JScrollPane( table );

			// install custom renderer
			final Icon[] icons = { UIManager.getIcon("FileChooser.newFolderIcon"), UIManager.getIcon("FileChooser.upFolderIcon"), UIManager.getIcon("FileChooser.homeFolderIcon") };
			table.getTableHeader().setDefaultRenderer( new DefaultTableCellRenderer() {
				public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
					setIcon(icons[column]);
					return this;
				}
			} );
			
			JFrame frame = new JFrame( "Test" );
			frame.setDefaultCloseOperation( WindowConstants.DISPOSE_ON_CLOSE );
			frame.add( scrollPane );

			frame.setSize( 400, 300 );
			frame.setVisible( true );
		} );
	}
}

[DevCharly]

Thanks, now I understand 😄

Background and foreground colors are set to null in DefaultTableCellRenderer.updateUI().
DefaultTableCellRenderer.getTableCellRendererComponent() would change those colors to non-null values,
but this method is overridden. So they stay null and FlatLaf does not restore them...