Positioning different objects over containers

Question

Dear Forum members,
Thanks to the help of woogly, I have a grid in my program, so my main looks like this:
public class Example extends JFrame {
public static void main(String[] args) {
new Example();
public Example() {
super("Grid Example");
setSize(new Dimension(300,300));
setDefaultCloseOperation(EXIT_ON_CLOSE);
getContentPane().add(new Grid(),BorderLayout.CENTER);
show();
1. Please tell me how to change the main to put two boxes with labels in the bottom of the grid so it will look like:
G R I D
Labl1 labl2
(The grid and at the bottom 2 labels side by side)
2. Do you now what is the difference between:
BorderLayout.CENTER and
SwingConstants.CENTER
What CENTER each of the mean and when to use each (CENTER is only for the example)?
3. I have seen a code using both of them. Like:
getContentPane().add(new JLabel("Player1", SwingConstants.CENTER),
BorderLayout.SOUTH);
Why both ?
Sorry I have so little Duke Dollars to offer..
Thanks
Eran

Answer 1

Hi.
What you need is to specify a LayoutManager that will actually do the layout in your ContentPane. Those constants are simply instructions to the LayoutManager where and how to place the sub-component.
The code that does what you ask could look like
public class Example extends JFrame {
  public static void main(String[] args) {
    new Example();
  public Example() {
    super("Grid Example");
    setSize(new Dimension(300,300));
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    getContentPane().setLayout(new BorderLayout());   // set the LayoutManager
    getContentPane().add(new Grid(),BorderLayout.CENTER);
    JPanel labels = new JPanel();
    labels.setLayout(new FlowLayout()); // or could be 'new GridLayout(1, 2)'
    labels.add(new JLabel("Label 1"));
    labels.add(new JLabel("Label 2"));
    getContentPane().add(labels, BorderLayout.SOUTH);
    show();
}Those two constnts are very different because
BorderLayout.CENTER is a string of value "Center" and
SwingConstants.CENTER is an int of value 0.
In this code
getContentPane().add(new JLabel("Player1", SwingConstants.CENTER), BorderLayout.SOUTH);
the
SwingConstants.CENTER is a second argument to the JLabel constructor indicating on how JLabel sould draw its text, and the BorderLayout.SOUTH is a second argument to add method.
Read about LayoutManager interface and implementing classes in the API docs
http://java.sun.com/j2se/1.4.2/docs/api/java/awt/LayoutManager.html
and there sould also be some tutorials on Layouts.
Filip