Move the selected item in JList up or down by clicking on the JButton placed on the JToolBar

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

Since DefaultListModel does not have a move method like DefaultTableModel#moveRow(int start, int end, int to), the DefaultListModel#get(int index), DefaultListModel#remove(int index), and DefaultListModel#add(int index, E element) methods are used in combination to move selected items up and down the JList.

Code

JButton up = new JButton("▲");
up.setFocusable(false);
up.addActionListener(e -> {
  int[] pos = list.getSelectedIndices();
  if (pos.length == 0) {
    return;
  }
  boolean isShiftDown = (e.getModifiers() & ActionEvent.SHIFT_MASK) != 0;
  int index0 = isShiftDown ? 0 : Math.max(0, pos[0] - 1);
  int idx = index0;
  for (int i : pos) {
    model.add(idx, model.remove(i));
    list.addSelectionInterval(idx, idx);
    idx++;
  }
  // scroll
  Rectangle r = list.getCellBounds(index0, index0 + pos.length);
  list.scrollRectToVisible(r);
});

JButton down = new JButton("▼");
down.setFocusable(false);
down.addActionListener(e -> {
  int[] pos = list.getSelectedIndices();
  if (pos.length == 0) {
    return;
  }
  boolean isShiftDown = (e.getModifiers() & ActionEvent.SHIFT_MASK) != 0;
  int max = model.getSize();
  int index = isShiftDown ? max : Math.min(max, pos[pos.length - 1] + 1);
  int index0 = index;
  // copy
  for (int i : pos) {
    int idx = Math.min(model.getSize(), ++index);
    model.add(idx, model.get(i));
    list.addSelectionInterval(idx, idx);
  }
  // clean
  for (int i = pos.length - 1; i >= 0; i--) {
    model.remove(pos[i]);
  }
  // scroll
  Rectangle r = list.getCellBounds(index0 - pos.length, index0);
  list.scrollRectToVisible(r);
});

References

• Move the selected item in JList up or down by clicking on the JButton placed on the JToolBar(Japanese)