Java GridBagLayout锚定不起作用，始终显示在JPanel的中间

我的应用程序处于全屏独占模式，我希望JPanel主面板处于最后一行，并在左右两侧进行一些填充。但当我运行这个程序时，它只显示屏幕中央的主面板。我也尝试过其他职位，但也不起作用

private void mainWindow()
    {   
        gls =(JPanel) mainUi.getGlassPane();
        gls.setLayout(new GridBagLayout());

        JPanel mainPanel = new JPanel(new GridLayout(4,1));
        nwGame = new JButton("New Game");
        nwGame.addActionListener(new ActionListener(){

            @Override
            public void actionPerformed(ActionEvent arg0) {
                // TODO Auto-generated method stub
                gls.setVisible(false);
                startGame(0);
                mainUi.repaint();
            }
        });

        ldGame = new JButton("Load Game");
        ldGame.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent ae)
            {

            }
        });

        changeProfile = new JButton("Change Profile");
        changeProfile.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent ae)
            {

            }
        });

        qtGame = new JButton("Quit Game");
        qtGame.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent ae)
            {

            }
        });

        GridBagConstraints gbc = new GridBagConstraints();
        gbc.ipadx = 10;
        gbc.ipady = 10;
        gbc.anchor = GridBagConstraints.LAST_LINE_START;

        mainPanel.add(nwGame);
        mainPanel.add(ldGame);
        mainPanel.add(changeProfile);
        mainPanel.add(qtGame);

        gls.add(mainPanel,gbc);
        gls.setVisible(true);

        mainUi.add(gls);
        if(!mainUi.isVisible())
            mainUi.setVisible(true);

    }       

每当我看到

它仅显示屏幕中央的主面板

…与GridBagLayout关联，我总是首先查看用户是如何实现weightx和WeightyGridBagConstraint属性的，正如预期的那样，您没有。使用它们

i、 e

---

这是

GridBagLayout

的默认行为。它将希望将所有组件放置在容器的中心。。。

   GridBagConstraints gbc = new GridBagConstraints();
   gbc.ipadx = 10;
   gbc.ipady = 10;
   gbc.anchor = GridBagConstraints.LAST_LINE_START;
   gbc.weightx = 1.0;
   gbc.weighty = 1.0;