更新时间:2023-12-05 18:33:52
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.