How can I properly center a JPanel ( FIXED SIZE ) inside a JFrame?

Question

Hi all! I\'m trying to solve an -apparently- simple problem, but I cannot fix it. I\'m working on a sample application with Java/Swing libraries; I have a JFrame and a JPan

Answer 1

create a panel by name "FixedPanel" with GridBagLayout and set preferred size to frame size then add your frame into FixedPanel.

Frame = new JFrame("CenterFrame");         
Frame.setLocation(0, 0);
Frame.setSize(new Dimension(400,400));//dim

JPanel FixedPanel = new JPanel(new GridBagLayout());
FixedPanel.setPreferredSize(Frame.getSize());

JPanel myPanel = new JPanel();
myPanel.setPreferredSize(new Dimension(100,100));
myPanel.setBackground(Color.BLACK);

FixedPanel.add(myPanel);
Frame.add(FixedPanel);
Frame.setVisible(true);