相关疑难解决方法(0)

在下面的GridBagLayout代码中,我希望在调整JFrame的大小以使其更小时,可以遵守JButton btn2的指定最小大小.但是当我使JFrame变小时,btn2会小于其最小尺寸然后消失.

有人能指出我正在做错的方向吗？也许我必须设置包含按钮的JPanel的最小大小？

任何帮助表示赞赏,谢谢!

    JFrame frame = new JFrame();
    frame.setSize(400,300);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel panel = new JPanel();
    panel.setMinimumSize(new Dimension(400,300));
    panel.setBackground(Color.RED);

    panel.setLayout(new GridBagLayout());
    GridBagConstraints gbc = null;

    JButton btn1 = new JButton("btn1");
    btn1.setPreferredSize(new Dimension(150,50));
    btn1.setMinimumSize(new Dimension(150,50));
    gbc = new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0, 
            GridBagConstraints.NORTHWEST, GridBagConstraints.NONE,
            new Insets(0,0,0,0), 0, 0);
    panel.add(btn1, gbc);

    JButton btn2 = new JButton("btn2");
    btn2.setPreferredSize(new Dimension(150,150));
    btn2.setMinimumSize(new Dimension(150,150));
    gbc = new GridBagConstraints(1, 0, 1, 1, 1.0, 1.0, 
            GridBagConstraints.NORTHWEST, GridBagConstraints.BOTH,
            new Insets(0,0,100,100), 0, 0);
    panel.add(btn2, gbc);

    frame.getContentPane().add(panel);
    frame.setVisible(true);