java - JTable Nimbus Look and Feel - how to make it clear which cell has focus

Question

When editing data in a JTable (Nimbus L & F), as the user tabs from cell to cell, it is not obvious which cell has focus. How can I make it clearer which cell has focus? I know there are a number of properties that can be set to modify Nimbus - does anyone know which property I want?

The screen shot below has only one property set to something other than the default:

UIManager.put("Table.showGrid", true);

Answer 1

• you have look at Renderer concept,

• by defaul works for Nimbus Look and Feel,

• some issue could be with JButtons components (JCheckBox e.i.), but a few times are answered or solved on this forum

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Font;
import java.awt.Graphics;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;
import javax.swing.Icon;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.RowSorter.SortKey;
import javax.swing.SortOrder;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableColumn;
import javax.swing.table.TableModel;
import javax.swing.table.TableRowSorter;

public class ImageChangeDemo extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTable table = new javax.swing.JTable();
    private JTable table1 = new javax.swing.JTable();
    private static Icon ascendingSortIcon;
    private static Icon descendingSortIcon;

    public static void main(String args[]) {
        //comment out the code below to try in Metal L&F
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    ascendingSortIcon = UIManager.getLookAndFeelDefaults().getIcon("Table.ascendingSortIcon");
                    descendingSortIcon = UIManager.getLookAndFeelDefaults().getIcon("Table.descendingSortIcon");
                    //UIManager.getLookAndFeelDefaults().put("Table.ascendingSortIcon", new BevelArrowIcon(BevelArrowIcon.UP, false, false));
                    //UIManager.getLookAndFeelDefaults().put("Table.descendingSortIcon", new BevelArrowIcon(BevelArrowIcon.DOWN, false, false));
                    break;
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ImageChangeDemo().setVisible(true);
            }
        });
    }

    public ImageChangeDemo() {
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        JScrollPane pane = new javax.swing.JScrollPane();
        //table.setAutoCreateRowSorter(true);
        table.setModel(new javax.swing.table.DefaultTableModel(
                new Object[][]{
                    {"a", "q", "h", "v"},
                    {"b", "m", "l", "h"},
                    {"d", "c", "a", "d"},
                    {"j", "o", "y", "e"}
                },
                new String[]{
                    "Col 1", "Col 2", "Col 3", "Col 4"
                }) {

            private static final long serialVersionUID = 1L;
            Class[] types = new Class[]{
                String.class, String.class, String.class, String.class
            };

            @Override
            public Class getColumnClass(int columnIndex) {
                return types[columnIndex];
            }
        });
        TableRowSorter<TableModel> sorter = new TableRowSorter<TableModel>(table.getModel()) {

            @Override
            public void toggleSortOrder(int column) {
                if (column >= 0 && column < getModelWrapper().getColumnCount() && isSortable(column)) {
                    List<SortKey> keys = new ArrayList<SortKey>(getSortKeys());
                    if (!keys.isEmpty()) {

                        SortKey sortKey = keys.get(0);
                        if (sortKey.getColumn() == column && sortKey.getSortOrder() == SortOrder.DESCENDING) {
                            setSortKeys(null);
                            return;
                        }
                    }
                }
                super.toggleSortOrder(column);
            }
        };
        table.setRowSorter(sorter);
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        pane.setViewportView(table);
        UIManager.getLookAndFeelDefaults().put("Table.ascendingSortIcon", new BevelArrowIcon(BevelArrowIcon.UP, false, false));
        UIManager.getLookAndFeelDefaults().put("Table.descendingSortIcon", new BevelArrowIcon(BevelArrowIcon.DOWN, false, false));
        SwingUtilities.updateComponentTreeUI(table);
        add(pane, BorderLayout.NORTH);
        JScrollPane pane1 = new javax.swing.JScrollPane();
        //table.setAutoCreateRowSorter(true);
        table1.setModel(new javax.swing.table.DefaultTableModel(
                new Object[][]{
                    {"a", "q", "h", "v"},
                    {"b", "m", "l", "h"},
                    {"d", "c", "a", "d"},
                    {"j", "o", "y", "e"}
                },
                new String[]{
                    "Col 1", "Col 2", "Col 3", "Col 4"
                }) {

            private static final long serialVersionUID = 1L;
            Class[] types = new Class[]{
                String.class, String.class, String.class, String.class
            };

            @Override
            public Class getColumnClass(int columnIndex) {
                return types[columnIndex];
            }
        });
        table1.setRowSorter(sorter);
        table1.setPreferredScrollableViewportSize(table1.getPreferredSize());
        pane1.setViewportView(table1);
        add(pane1, BorderLayout.SOUTH);

        for (int i = 0; i < table1.getColumnCount(); i++) {
            RowColorRenderer rowRenderer = new RowColorRenderer(i);
            TableColumn column = table1.getColumnModel().getColumn(i);
            column.setCellRenderer(rowRenderer);
        }
        pack();
    }

    private class RowColorRenderer extends DefaultTableCellRenderer {

        private static final long serialVersionUID = 1L;
        private int colNo = 0;

        RowColorRenderer(int col) {
            colNo = col;
        }

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value,
                boolean isSelected, boolean hasFocus, int row, int column) {
            Component comp = super.getTableCellRendererComponent(table, value,
                    isSelected, hasFocus, row, column);
            JComponent jc = (JComponent) comp;
            if (!isSelected) {
                if (table.getValueAt(row, colNo) != null) {
                    String str = table.getValueAt(row, colNo).toString();
                    if (!str.isEmpty()) {
                        if (Pattern.compile("\d").matcher(str).find()) {
                            if (((Pattern.compile("[02468]").matcher(str).find()))
                                    && (!(Pattern.compile("[13579]").matcher(str).find()))) {
                                setForeground(Color.magenta);
                                setBackground(Color.orange);
                            } else if ((!(Pattern.compile("[02468]").matcher(str).find()))
                                    && ((Pattern.compile("[13579]").matcher(str).find()))) {
                                setForeground(Color.blue);
                                setBackground(Color.yellow);
                            } else if (((Pattern.compile("[02468]").matcher(str).find()))
                                    && ((Pattern.compile("[13579]").matcher(str).find()))) {
                                setForeground(Color.red);
                                setBackground(Color.cyan);
                            }
                            setFont(new Font("Serif", Font.BOLD, 12));
                            setHorizontalAlignment(CENTER);
                        } else {
                            setBackground(table.getBackground());
                            setForeground(table.getForeground());
                            setFont(new Font("Serif", Font.PLAIN, 8));
                            setHorizontalAlignment(CENTER);
                        }
                    }
                }
            } else {
                if (hasFocus) {
                    setFont(new Font("Serif", Font.BOLD, 12));
                    setForeground(Color.magenta);
                    setBackground(Color.orange);
                }
            }
            return this;
        }
    }

    static class BevelArrowIcon implements Icon {

        public static final int UP = 0;         // direction
        public static final int DOWN = 1;
        private static final int DEFAULT_SIZE = 11;
        private Color edge1;
        private Color edge2;
        private Color fill;
        private int size;
        private int direction;

        public BevelArrowIcon(int direction, boolean isRaisedView, boolean isPressedView) {
            if (isRaisedView) {
                if (isPressedView) {
                    init(UIManager.getColor("controlLtHighlight"), UIManager.getColor("controlDkShadow"), UIManager.getColor("controlShadow"), DEFAULT_SIZE, direction);
                } else {
                    init(UIManager.getColor("controlHighlight"), UIManager.getColor("controlShadow"), UIManager.getColor("control"), DEFAULT_SIZE, direction);
                }
            } else {
                if (isPressedView) {
                    init(UIManager.getColor("controlDkShadow"), UIManager.getColor("controlLtHighlight"), UIManager.getColor("controlShadow"), DEFAULT_SIZE, direction);
                } else {
                    init(UIManager.getColor("controlShadow"), UIManager.getColor("controlHighlight"), UIManager.getColor("control"), DEFAULT_SIZE, direction);
                }
            }
        }

        public BevelArrowIcon(Color edge1, Color edge2, Color fill, int size, int direction) {
            init(edge1, edge2, fill, size, direction);
        }

        @Override
        public void paintIcon(Component c, Graphics g, int x, int y) {
            switch (direction) {
                case DOWN:
                    drawDownArrow(g, x, y);
                    break;
                case UP:
                    drawUpArrow(g, x, y);
                    break;
            }
        }

        @Override
        public int getIconWidth() {
            return size;
        }

        @Override
        public int getIconHeight() {
            return size;
        }

        private void init(Color edge1, Color edge2, Color fill, int size, int direction) {
            edge1 = Color.red;
            edge2 = Color.blue;
            this.edge1 = edge1;
            this.edge2 = edge2;
            this.fill = fill;
            this.size = size;
            this.direction = direction;
        }

        private void drawDownArrow(Graphics g, int xo, int yo) {
            g.setColor(edge1);
            g.drawLine(xo, yo, xo + size - 1, yo);
            g.drawLine(xo, yo + 1, xo + size - 3, yo + 1);
            g.setColor(edge2);
            g.drawLine(xo + size - 2, yo + 1, xo + size - 1, yo + 1);