为JComboBox的Items中的值设置工具提示，作为JTable中的CellEditor

Question

我想为自定义组合框中的值设置工具提示值。基本上，我的组合框包含一个姓名缩写的列表-
当他们将鼠标悬停在上方时，我希望它显示该姓名的全名。我的组合框基本上是JTable的一个单元格/列，它具有自己的TableCellRenderer和DefaultCellEditor。该列表是一个JList（模型中的内部类）-iv尝试直接设置’setToolTipText’方法，但这似乎不起作用。

这是代码：

• JTable中的代码：*

    public void setupUserCombo(Container container){
          TableColumn col = getColumnModel().getColumn(3);
          Set<ComboUser> values = new LinkedHashSet<ComboUser>();

          ComboUser comboUser = new ComboUser(new User("Test User"));
          values.add(comboUser);

          col.setCellEditor(new MyComboBoxEditor((ComboUser[])values.toArray(new ComboUser[0])));
          col.setCellRenderer(new MyComboBoxRenderer((ComboUser[])values.toArray(new ComboUser[0])));
          repaint();
    }

    public class MyComboBoxRenderer extends JComboBox implements TableCellRenderer {
        private static final long serialVersionUID = 1L;

        public MyComboBoxRenderer(ComboUser[] items) {
            super(items);
            repaint();
        }

        public Component getTableCellRendererComponent(JTable table, Object value,
                boolean isSelected, boolean hasFocus, int row, int column) {
            if (value != null){
                System.out.println("Setting tooltip");
                ((ComboUser)value).setToolTipText("TESTING!!");
            }
            setSelectedItem(value);

            return this;
        }
    }

    public class MyComboBoxEditor extends DefaultCellEditor {
        private static final long serialVersionUID = 1L;

        public MyComboBoxEditor(ComboUser[] items) {
            super(new JComboBox(items));
        }
    }

模型中的子类：

    public class ComboUser extends JLabel{

        private User user;

        public ComboUser(User user){
            if (user != null){
                this.user = user;
            } else {
                this.user = new User("");
            }
        }

        @Override
        public String toString() {
            return user.getInitials();
        }

Answer 1

如果要在编辑组合框中显示工具提示，则必须在该组合框的自定义渲染器中进行操作。下面是一个简短的示例：

    // some data
    User[] users = new User[] { 
            new User("Clara Zetkin", "CZ"),
            new User("Rosa Luxemburg", "RL"),
            new User("Susan Sontag", "SS"),
    };
    // the renderer for use in the editor
    ListCellRenderer comboRenderer = new DefaultListCellRenderer() {

        @Override
        public Component getListCellRendererComponent(JList<?> list,
                Object value, int index, boolean isSelected,
                boolean cellHasFocus) {
            if (value instanceof User) {
                setToolTipText(((User) value).getName());
                value = ((User) value).getInitials();
            } else {
                setToolTipText(null);
            }
            return super.getListCellRendererComponent(list, value, index, isSelected,
                    cellHasFocus);
        }

    };
    JComboBox editingCombo = new JComboBox(users);
    editingCombo.setRenderer(comboRenderer);

    JTable table = new JTable(3, 2);
    // set up the editor for the first column
    table.getColumnModel().getColumn(0).setCellEditor(new DefaultCellEditor(editingCombo));
    // the renderer to use in the table
    TableCellRenderer renderer = new DefaultTableCellRenderer() {

        @Override
        protected void setValue(Object value) {
            if (value instanceof User) {
                setToolTipText(((User) value).getInitials());
                value = ((User) value).getName();
            } else {
                setToolTipText(null);
            }
            super.setValue(value);
        }

    };
    table.getColumnModel().getColumn(0).setCellRenderer(renderer);