Help with LayoutManagers

[BiteMuncher]

Hi, I would like to create a JFrame with the following setup:
A contentPane with 3 panels added called topPnl, middlePnl and lowerPnl aranged from top to bottom.

There is an array of smaller panels called slotPanels[] that each hold a single JComboBox called slots[].
There is a loop that adds a certain number of these panels in a gridLayout to each of the top middle and lower panels.
All of this works fine but because the contentPane uses a gridLayout the top middle and lower panels are the same size, and because each of these three panels hold a different number of slotPanels, the slotPanels are not evenly spaced. Does anyone have another suggestion on how to get all the slotPanels evenly spaced. the top middle and lower panels do not need to be the same height. Here is my code:

public class SelectionFrame extends JFrame implements ActionListener
{
    private JButton addBtns[] = new JButton[11];
    private JPanel slotPanels[] = new JPanel[11];
    private JComboBox slots[] = new JComboBox[11];
    
    public SelectionFrame()
    {
        createMenu();
        //create panels for empty slots
        JPanel topPnl = new JPanel();
            topPnl.setLayout(new GridLayout(3,2,5,5));
            topPnl.setBorder(new TitledBorder("Top Order"));
        JPanel middlePnl = new JPanel(); 
            middlePnl.setLayout(new GridLayout(2,2,5,5));
            middlePnl.setBorder(new TitledBorder("Middle Order"));
        JPanel lowerPnl = new JPanel(); 
            lowerPnl.setLayout(new GridLayout(6,2,5,5));
            lowerPnl.setBorder(new TitledBorder("Lower Order"));

            //add contents to slots and slots into panels
        FlowLayout slotSetup = new FlowLayout(FlowLayout.LEFT,5,3);
        for(int i=0; i<slots.length; i++)
        {
            slotPanels[i] = new JPanel();
            slotPanels[i].setLayout(slotSetup);
            addBtns[i] = new JButton("Add");
            addBtns[i].addActionListener(this);
            slotPanels[i].add(addBtns[i]);
            slots[i] = new JComboBox();
            Font f = new Font("arial", Font.BOLD, 12);
            slots[i].setFont(f);
            slots[i].addItem("Empty                    ");
            slotPanels[i].add(slots[i]);
            if(i<3)
                topPnl.add(slotPanels[i]);
            else
                if(i<5)
                    middlePnl.add(slotPanels[i]);
                else
                    lowerPnl.add(slotPanels[i]);
        }

        Container c = getContentPane();
        c.setLayout(new GridLayout(3,1,5,5));
        c.add(topPnl);
        c.add(middlePnl);
        c.add(lowerPnl);
}

[Fubarable]

Can you post a picture of what you have and another of what you are trying to achieve?

Also, you'll want to create and post an SSCCE

[Fubarable]

Also, if you don't care if top, middle and bottom JPanels are the same size, you could always use a BoxLayout to hold them.

      Container c = getContentPane();
      //!! c.setLayout(new GridLayout(3, 1, 5, 5));
      c.setLayout(new BoxLayout(c, BoxLayout.PAGE_AXIS));
      c.add(topPnl);
      c.add(middlePnl);
      c.add(lowerPnl);

[BiteMuncher]

Also, if you don't care if top, middle and bottom JPanels are the same size, you could always use a BoxLayout to hold them.

      Container c = getContentPane();
      //!! c.setLayout(new GridLayout(3, 1, 5, 5));
      c.setLayout(new BoxLayout(c, BoxLayout.PAGE_AXIS));
      c.add(topPnl);
      c.add(middlePnl);
      c.add(lowerPnl);

Thanks!, they are evenly spaced now.
How does the BoxLayout space the components?

[Fubarable]

Have a look here: The BoxLayout