Keep visible the JPopupMenu while clicking on CheckBox

• download example.jar
• download src.zip
• repository

Code

JMenuItem mi = new JMenuItem(" ");
mi.setLayout(new BorderLayout());
mi.add(new JCheckBox(title) {
  private transient MouseAdapter handler;

  @Override public void updateUI() {
    removeMouseListener(handler);
    removeMouseMotionListener(handler);
    super.updateUI();
    handler = new DispatchParentHandler();
    addMouseListener(handler);
    addMouseMotionListener(handler);
    setFocusable(false);
    setOpaque(false);
  }
});
popup.add(mi);

popup.add(new JCheckBoxMenuItem("keeping open #2") {
  @Override public void updateUI() {
    super.updateUI();
    setUI(new BasicCheckBoxMenuItemUI() {
      @Override protected void doClick(MenuSelectionManager msm) {
        // super.doClick(msm);
        System.out.println("MenuSelectionManager: doClick");
        menuItem.doClick(0);
      }
    });
  }
});

// https://bugs.openjdk.java.net/browse/JDK-8165234
// Provide a way to not close toggle menu items on mouse click on component level
// JDK 9
JMenuItem menuItem = new JMenuItem("JMenuItem");
menuItem.putClientProperty("CheckBoxMenuItem.doNotCloseOnMouseClick", true);

References

• swing - How to prevent JPopUpMenu disappearing when checking checkboxes in it? - Stack Overflow
• Keep visible the JPopupMenu while clicking on CheckBox(Japanese)
• [JDK-8165234] Provide a way to not close toggle menu items on mouse click on component level - Java Bug System

The JRadioButton that is currently selected in the ButtonGroup set as the default focus component

• download example.jar
• download src.zip
• repository

Code

buttons.setFocusTraversalPolicyProvider(true);
buttons.setFocusTraversalPolicy(new LayoutFocusTraversalPolicy() {
  @Override public Component getDefaultComponent(Container focusCycleRoot) {
    ButtonModel selection = bg.getSelection();
    for (Component c: focusCycleRoot.getComponents()) {
      JRadioButton r = (JRadioButton) c;
      if (r.getModel().equals(selection)) {
        return r;
      }
    }
    return super.getDefaultComponent(focusCycleRoot);
  }
});

References

• [JDK-8033699] Incorrect radio button behavior - Java Bug System
• [JDK-8154043] Fields not reachable anymore by tab-key, because of new tabbing behaviour of radio button groups. - Java Bug System
• java - Get the focus in a ButtonGroup of JRadioButtons to go to the currently selected item instead of first - Stack Overflow
• The JRadioButton that is currently selected in the ButtonGroup set as the default focus component (Japanese)

How to hide the JTableHeader

• download example.jar
• download src.zip
• repository

Code

final JScrollPane scrollPane = new JScrollPane(table);
JCheckBox check = new JCheckBox("JTableHeader visible: ", true);
check.addActionListener(new ActionListener() {
  @Override public void actionPerformed(ActionEvent e) {
    JCheckBox cb = (JCheckBox) e.getSource();
    // table.getTableHeader().setVisible(cb.isSelected());
    scrollPane.getColumnHeader().setVisible(cb.isSelected());
    scrollPane.revalidate();
  }
});

References

• How to hide the JTableHeader(Japanese)

Validating input on an editable JComboBox with InputVerifier and JLayer

• download example.jar
• download src.zip
• repository

Code

JComboBox<String> comboBox = new JComboBox<String>(model) {
  @Override public void updateUI() {
    getActionMap().put(ENTER_PRESSED, null);
    super.updateUI();
    final JComboBox<String> cb = this;
    final Action defalutEnterPressedAction = getActionMap().get(ENTER_PRESSED);
    getActionMap().put(ENTER_PRESSED, new AbstractAction() {
      @Override public void actionPerformed(ActionEvent e) {
        boolean isPopupVisible = isPopupVisible();
        setPopupVisible(false);
        DefaultComboBoxModel<String> m = (DefaultComboBoxModel<String>) getModel();
        String str = Objects.toString(getEditor().getItem(), "");
        if (m.getIndexOf(str) < 0 && getInputVerifier().verify(cb)) {
          m.removeElement(str);
          m.insertElementAt(str, 0);
          if (m.getSize() > 10) {
            m.removeElementAt(10);
          }
          setSelectedIndex(0);
          setPopupVisible(isPopupVisible);
        } else {
          defalutEnterPressedAction.actionPerformed(e);
        }
      }
    });
  }
};
comboBox.setEditable(true);
comboBox.setInputVerifier(new LengthInputVerifier());
comboBox.setEditor(new BasicComboBoxEditor() {
  private Component editorComponent;
  @Override public Component getEditorComponent() {
    if (editorComponent == null) {
      JTextComponent tc = (JTextComponent) super.getEditorComponent();
      editorComponent = new JLayer<JTextComponent>(tc, new ValidationLayerUI());
    }
    return editorComponent;
  }
});

class LengthInputVerifier extends InputVerifier {
  private static final int MAX_LEN = 6;
  @Override public boolean verify(JComponent c) {
    if (c instanceof JComboBox) {
      JComboBox cb = (JComboBox) c;
      String str = Objects.toString(cb.getEditor().getItem(), "");
      return MAX_LEN - str.length() >= 0;
    }
    return false;
  }
}

References

• How to Decorate Components with the JLayer Class (The Java™ Tutorials > Creating a GUI With JFC/Swing > Using Other Swing Features)
• Validating input on an editable JComboBox with InputVerifier and JLayer(Japanese)

Save and load the state of a JTable and TableColumn(name, width, position and sortKey)

• download example.jar
• download src.zip
• repository

Code

class DefaultTableModelPersistenceDelegate extends DefaultPersistenceDelegate {
  @Override protected void initialize(
        Class<?> type, Object oldInstance, Object newInstance, Encoder encoder) {
    super.initialize(type, oldInstance,  newInstance, encoder);
    DefaultTableModel m = (DefaultTableModel) oldInstance;
    for (int row = 0; row < m.getRowCount(); row++) {
      for (int col = 0; col < m.getColumnCount(); col++) {
        Object[] o = new Object[] {m.getValueAt(row, col), row, col};
        encoder.writeStatement(new Statement(oldInstance, "setValueAt", o));
      }
    }
  }
}

File file = File.createTempFile("output", ".xml");
try (XMLEncoder xe = new XMLEncoder(new BufferedOutputStream(new FileOutputStream(file)))) {
  xe.setPersistenceDelegate(
    RowSorter.SortKey.class,
    new DefaultPersistenceDelegate(new String[] {"column", "sortOrder"}));
  xe.writeObject(table.getRowSorter().getSortKeys());
//...

class TableColumnModelPersistenceDelegate extends DefaultPersistenceDelegate {
  @Override protected void initialize(
      Class<?> type, Object oldInstance, Object newInstance, Encoder encoder) {
    super.initialize(type, oldInstance, newInstance, encoder);
    DefaultTableColumnModel m = (DefaultTableColumnModel) oldInstance;
    for (int col = 0; col < m.getColumnCount(); col++) {
      Object[] o = {m.getColumn(col)};
      encoder.writeStatement(new Statement(oldInstance, "addColumn", o));
    }
  }
}

References

• Save and load the state of a JTable and TableColumn(name, width, position and sortKey)(Japanese)