Java Swing - JList with Text Field Filter Example

This example shows how to use JTextField to filter JList items.

public class JListFilterExample {
    public static void main(String[] args) {
        List<Employee> employees = EmployeeDataAccess.getEmployees();
        DefaultListModel<Employee> model = new DefaultListModel<>();
        employees.forEach(model::addElement);
        JList<Employee> jList = new JList<>(model);
        jList.setCellRenderer(createListRenderer());
        JPanel panel = JListFilterDecorator.decorate(jList, JListFilterExample::employeeFilter);
        JFrame frame = createFrame();
        frame.add(panel);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    private static boolean employeeFilter(Employee emp, String str) {
        return emp.getName().toLowerCase().contains(str.toLowerCase());
    }

    private static ListCellRenderer<? super Employee> createListRenderer() {
        return new DefaultListCellRenderer() {
            private Color background = new Color(0, 100, 255, 15);
            private Color defaultBackground = (Color) UIManager.get("List.background");

            @Override
            public Component getListCellRendererComponent(JList<?> list, Object value, int index,
                                                          boolean isSelected, boolean cellHasFocus) {
                Component c = super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
                if (c instanceof JLabel) {
                    JLabel label = (JLabel) c;
                    Employee emp = (Employee) value;
                    label.setText(String.format("%s [%s]", emp.getName(), emp.getDept()));
                    if (!isSelected) {
                        label.setBackground(index % 2 == 0 ? background : defaultBackground);
                    }
                }
                return c;
            }
        };
    }

    private static JFrame createFrame() {
        JFrame frame = new JFrame("JList Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(new Dimension(600, 300));
        return frame;
    }
}

public class JListFilterDecorator {
    public static <T> JPanel decorate(JList<T> jList, BiPredicate<T, String> userFilter) {
        if (!(jList.getModel() instanceof DefaultListModel)) {
            throw new IllegalArgumentException("List model must be an instance of DefaultListModel");
        }
        DefaultListModel<T> model = (DefaultListModel<T>) jList.getModel();
        List<T> items = getItems(model);
        JTextField textField = new JTextField();
        textField.getDocument().addDocumentListener(new DocumentListener() {
            @Override
            public void insertUpdate(DocumentEvent e) {
                filter();
            }

            @Override
            public void removeUpdate(DocumentEvent e) {
                filter();
            }

            @Override
            public void changedUpdate(DocumentEvent e) {
                filter();
            }

            private void filter() {
                model.clear();
                String s = textField.getText();
                for (T item : items) {
                    if(userFilter.test(item, s)){
                        model.addElement(item);
                    }
                }
            }
        });

        JPanel panel = new JPanel(new BorderLayout());
        panel.add(textField, BorderLayout.NORTH);
        JScrollPane pane = new JScrollPane(jList);
        panel.add(pane);
        return panel;
    }

    private static <T> List<T> getItems(DefaultListModel<T> model) {
        List<T> list = new ArrayList<>();
        for (int i = 0; i < model.size(); i++) {
            list.add(model.elementAt(i));
        }
        return list;
    }
}

public class Employee {
    private String name;
    private String dept;
    private String phone;
    private String address;
    .............
}

Output

Example Project

Dependencies and Technologies Used:

• datafactory 0.8: Library to generate data for testing.
• JDK 1.8
• Maven 3.3.9