JListのセルにJCheckBoxを使用する

概要

JListのセルにJCheckBoxを使用して、チェックボックスの一覧を作成します。

Screenshot

Download

• Runnable JAR example.jar
• Source code src.zip
• Repository GitHub

サンプルコード

class CheckBoxCellRenderer<E extends CheckBoxNode> extends JCheckBox
    implements ListCellRenderer<E>, MouseListener, MouseMotionListener {
  private int rollOverRowIndex = -1;

  @Override public Component getListCellRendererComponent(
        JList<? extends E> list, E value, int index,
        boolean isSelected, boolean cellHasFocus) {
    this.setOpaque(true);
    if (isSelected) {
      this.setBackground(list.getSelectionBackground());
      this.setForeground(list.getSelectionForeground());
    } else {
      this.setBackground(list.getBackground());
      this.setForeground(list.getForeground());
    }
    this.setSelected(value.selected);
    this.getModel().setRollover(index == rollOverRowIndex);
    this.setText(value.text);
    return this;
  }

  @Override public void mouseExited(MouseEvent e) {
    if (rollOverRowIndex >= 0) {
      JList<?> l = (JList<?>) e.getComponent();
      l.repaint(l.getCellBounds(rollOverRowIndex, rollOverRowIndex));
      rollOverRowIndex = -1;
    }
  }

  @Override public void mouseClicked(MouseEvent e) {
    if (e.getButton() == MouseEvent.BUTTON1) {
      JList<?> l = (JList<?>) e.getComponent();
      Point p = e.getPoint();
      int index  = l.locationToIndex(p);
      if (index >= 0) {
        @SuppressWarnings("unchecked")
        DefaultListModel<CheckBoxNode> m =
            (DefaultListModel<CheckBoxNode>) l.getModel();
        CheckBoxNode n = m.get(index);
        m.set(index, new CheckBoxNode(n.text, !n.selected));
        l.repaint(l.getCellBounds(index, index));
      }
    }
  }

  @Override public void mouseMoved(MouseEvent e) {
    JList<?> l = (JList<?>) e.getComponent();
    int index = l.locationToIndex(e.getPoint());
    if (index != rollOverRowIndex) {
      rollOverRowIndex = index;
      l.repaint();
    }
  }

  @Override public void mouseEntered(MouseEvent e)  {
    /* not needed */
  }

  @Override public void mousePressed(MouseEvent e)  {
    /* not needed */
  }

  @Override public void mouseReleased(MouseEvent e) {
    /* not needed */
  }

  @Override public void mouseDragged(MouseEvent e)  {
    /* not needed */
  }
}

解説

• Box
  • Box.createVerticalBox()にJCheckBoxを追加
  • JCheckBox#setAlignmentX(Component.LEFT_ALIGNMENT);で左揃えに設定

• JList
  • JCheckBoxを継承するListCellRendererを設定
  • チェックボックスのロールオーバーなどは、JListにマウスリスナーを設定して描画
  • JList#processMouseEvent、JList#processMouseMotionEventのオーバーライドと、JList#putClientProperty("List.isFileList", Boolean.TRUE);でクリックが有効になる領域をチェックボックスの幅に制限

JList list1 = new JList(model) {
  private CheckBoxCellRenderer renderer;
  @Override public void updateUI() {
    setForeground(null);
    setBackground(null);
    setSelectionForeground(null);
    setSelectionBackground(null);
    if (renderer != null) {
      removeMouseListener(renderer);
      removeMouseMotionListener(renderer);
    }
    super.updateUI();
    renderer = new CheckBoxCellRenderer();
    setCellRenderer(renderer);
    addMouseListener(renderer);
    addMouseMotionListener(renderer);
  }

  // @see SwingUtilities2.pointOutsidePrefSize(...)
  private boolean pointOutsidePrefSize(Point p) {
    int index = locationToIndex(p);
    DefaultListModel m = (DefaultListModel) getModel();
    CheckBoxNode n = (CheckBoxNode) m.get(index);
    Component c = getCellRenderer().getListCellRendererComponent(
                    this, n, index, false, false);
    // c.doLayout();
    Dimension d = c.getPreferredSize();
    Rectangle rect = getCellBounds(index, index);
    rect.width = d.width;
    return index < 0 || !rect.contains(p);
  }

  @Override protected void processMouseEvent(MouseEvent e) {
    if (!pointOutsidePrefSize(e.getPoint())) {
      super.processMouseEvent(e);
    }
  }

  @Override protected void processMouseMotionEvent(MouseEvent e) {
    if (!pointOutsidePrefSize(e.getPoint())) {
      super.processMouseMotionEvent(e);
    } else {
      e = new MouseEvent(
        (Component) e.getSource(), MouseEvent.MOUSE_EXITED, e.getWhen(),
        e.getModifiers(), e.getX(), e.getY(),
        e.getXOnScreen(), e.getYOnScreen(),
        e.getClickCount(), e.isPopupTrigger(), MouseEvent.NOBUTTON);
      super.processMouseEvent(e);
    }
  }
};

• JTree
  • JCheckBoxを継承するTreeCellRendererを設定
    • JTreeの葉ノードをJCheckBoxにするで作成したセルレンダラーを使用
  • JTree#setRootVisible(false)でルートノードを非表示に設定
    • JTreeのルートノードを非表示に設定する

class CheckBoxNodeRenderer extends JCheckBox implements TreeCellRenderer {
  private TreeCellRenderer renderer = new DefaultTreeCellRenderer();
  @Override public Component getTreeCellRendererComponent(
    JTree tree, Object value, boolean selected, boolean expanded,
    boolean leaf, int row, boolean hasFocus) {
    if (leaf && value instanceof DefaultMutableTreeNode) {
      this.setOpaque(false);
      Object userObject = ((DefaultMutableTreeNode) value).getUserObject();
      if (userObject instanceof CheckBoxNode) {
        CheckBoxNode node = (CheckBoxNode) userObject;
        this.setText(node.text);
        this.setSelected(node.selected);
      }
      return this;
    }
    return renderer.getTreeCellRendererComponent(
             tree, value, selected, expanded, leaf, row, hasFocus);
  }
}

class CheckBoxNodeEditor extends JCheckBox implements TreeCellEditor {
  private final JTree tree;
  public CheckBoxNodeEditor(JTree tree) {
    super();
    this.tree = tree;
    setOpaque(false);
    setFocusable(false);
    addActionListener(new ActionListener() {
      @Override public void actionPerformed(ActionEvent e) {
        stopCellEditing();
      }
    });
  }

  @Override public Component getTreeCellEditorComponent(
    JTree tree, Object value, boolean isSelected, boolean expanded,
    boolean leaf, int row) {
    if (leaf && value instanceof DefaultMutableTreeNode) {
      Object userObject = ((DefaultMutableTreeNode) value).getUserObject();
      if (userObject instanceof CheckBoxNode) {
        this.setSelected(((CheckBoxNode) userObject).selected);
      } else {
        this.setSelected(false);
      }
      this.setText(value.toString());
    }
    return this;
  }

  @Override public Object getCellEditorValue() {
    return new CheckBoxNode(getText(), isSelected());
  }

  @Override public boolean isCellEditable(EventObject e) {
    return (e instanceof MouseEvent);
  }

  // Copied from AbstractCellEditor
  // protected EventListenerList listenerList = new EventListenerList();
  // transient protected ChangeEvent changeEvent = null;
  @Override public boolean shouldSelectCell(EventObject anEvent) {
    // ...

参考リンク

• JTreeの葉ノードをJCheckBoxにする
• JTreeのルートノードを非表示に設定する

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