如何使按钮用完BorderLayout中的所有空间而没有空白？

Question

我有一个程序可以创建一个填充有随机颜色的8x8网格（已经完成了此操作），我应该在底部添加一个按钮，该按钮应该填充整个底部，这将用于重置颜色。 我已经有了网格和按钮，但是，我的按钮并没有填满底部的整个空间，而只占一半。 如何使其充满整个空间？

我的代码：

public void createGUI() 
{
    guiFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    guiFrame.setTitle("Label demo");
    JPanel mainPanel = new JPanel();
    JPanel gridPanel = new JPanel();
    JPanel buttonPanel = new JPanel();
    JButton refreshButton = new JButton("Press me to refresh labels");
    mainPanel.setLayout(new BorderLayout());
    guiFrame.getContentPane().add(mainPanel);
    gridPanel.setLayout(new GridLayout(8, 8));
    for (int i = 0; i < arrayLabels.length; i++)
    {
        arrayLabels[i] = new ColorLabel(80, 80, new Color(rand.nextInt()), 0, new Color(rand.nextInt()));
    }

    for (int i = 0; i < 8*8; i++)
    {
        gridPanel.add(arrayLabels[i]);
    }
    guiFrame.getContentPane().add(gridPanel);
    buttonPanel.add(refreshButton);
    guiFrame.getContentPane().add(buttonPanel, BorderLayout.SOUTH);
    guiFrame.setVisible(true);
}

我程序的输出当前是这样的： https : //imgur.com/a/fw1Bx92

Answer 1

还要设置刷新按钮的JPanel布局！ 我在下面举一个例子，您可以检查一下：

public static void createGUI() 
{
    JFrame guiFrame = new JFrame("a");
    guiFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    guiFrame.setTitle("Label demo");
    JPanel mainPanel = new JPanel();
    JPanel gridPanel = new JPanel();
    JPanel buttonPanel = new JPanel(new BorderLayout());
    JButton refreshButton = new JButton("Press me to refresh labels");
    mainPanel.setLayout(new BorderLayout());
    guiFrame.getContentPane().add(mainPanel);
    gridPanel.setLayout(new GridLayout(8, 8));
    JLabel arrayLabels[] = new JLabel[64];
    for (int i = 0; i < 64; i++)
    {
        arrayLabels[i] = new JLabel("a");
    }

    for (int i = 0; i < 8*8; i++)
    {
        gridPanel.add(arrayLabels[i]);
    }
    guiFrame.getContentPane().setLayout(new BorderLayout());
    guiFrame.getContentPane().add(gridPanel,BorderLayout.CENTER);
    buttonPanel.add(refreshButton,BorderLayout.CENTER);
    guiFrame.getContentPane().add(buttonPanel, BorderLayout.SOUTH);
    guiFrame.setVisible(true);
}