Automatically size JPanel inside JFrame

Question

I have a JPanel subclass on which I add buttons, labels, tables, etc. To show on screen it I use JFrame:

MainPanel mainPanel = new          


        

Answer 1

You can set a layout manager like BorderLayout and then define more specifically, where your panel should go:

MainPanel mainPanel = new MainPanel();
JFrame mainFrame = new JFrame();
mainFrame.setLayout(new BorderLayout());
mainFrame.add(mainPanel, BorderLayout.CENTER);
mainFrame.pack();
mainFrame.setVisible(true);

This puts the panel into the center area of the frame and lets it grow automatically when resizing the frame.