how to center position progressbar in java

Question

i want my progressbar at the center of the sreen. i already tried...

setLocationRelativeTo(null);

but when i run the program it didnt work. somehow it is not in the middle of the screen. Please help me. See image.

HERE ARE MY CODES

public class progressbar extends JFrame {
    private JProgressBar jp;
    private Timer t;
    int i = 0;

public progressbar() {

    setTitle("Loading...");
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    getContentPane().setLayout(new GridBagLayout());
    setLocationRelativeTo(null);
    setUndecorated(true);
    setVisible(true);
    jp = new JProgressBar();
    // Paint the percent complete on progress bar
    jp.setStringPainted(true);
    jp.setPreferredSize(new Dimension(500, 30));
    jp.setMinimum(0);
    jp.setMaximum(1000);
    getContentPane().add(jp);
    pack();
    // Create a timer that executes for every 2 millisec
    t = new Timer(2, new ActionListener() {
        public void actionPerformed(ActionEvent ae) {
            jp.setValue(i++);
            if (i == 1000) {
                t.stop();
                setVisible(false);
                loginInterface l = new loginInterface();
                l.txtUser.requestFocus();
            }
        }
    });
    // Start the timer
    t.start();
}

The GridBagConstraints

Anchor is Center, Grid Height 1, Grid Width 1, Grid X -1, Grid Y - 1

Answer 1

You need to create GridBagConstraints and define anchor (among others like x_weight) to center in GridBagLayout

Then add the component to the layout like this

    GridBagLayout layout = new GridBagLayout();
    GridBagConstraints cons = new GridBagConstraints();

//set the constraints properties

layout.addLayoutComponent(JProgressBar, cons);

then

setLayout(layout)