Position panel in centre of another panel

Question

This is one of those things that should be straightforward, but just isn't working out that way.
I have a JPanel called PanelA.
Prompted by a user action, I just want to add another (smaller) JPanel called PanelB in the centre of PanelA.
I've tried using a BorderLayout on PanelA, and doing this :
PanelA.add(PanelB, BorderLayout.CENTER);but this adds PanelB at the top of PanelA.
Does anyone know how I can just have this smaller panel appear dead-centre in the larger panel?

Answer 1

if you have licence for Borland JBCL library (VerticalFlowLayout)
you can use this code here.
public static final void addToPanel(Container xy, JPanel x, String title) {
    String name = x.getName();
    if (name == title) {
      System.err.print("ERROR PANEL IS ALREADY THERE");
      return;
    clearPanel(x);
    EtchedBorder border1 = new EtchedBorder(EtchedBorder.RAISED, Color.white,
                                            new Color(148, 145, 140));
    TitledBorder titledBorder1;
    titledBorder1 = new TitledBorder(border1, title);
    JPanel pan = new JPanel();
    JPanel pan2 = new JPanel();
    JPanel containerPanel = new JPanel();
    pan2.setLayout(new FlowLayout());
    VerticalFlowLayout vertical = new VerticalFlowLayout();
    vertical.setAlignment(VerticalFlowLayout.MIDDLE);
    pan.setLayout(vertical);
    containerPanel.setBorder(titledBorder1);
    containerPanel.add(xy, BorderLayout.CENTER);
    pan2.add(containerPanel);
    pan.add(pan2);
    x.add(pan, BorderLayout.CENTER);
    x.validate();
    x.repaint();
    // x.setName(title);
    x.updateUI();