java - GridBagLayout 不遵守 gridx 和 gridy

Question

我在制作的游戏中无法正确布置某些组件。我的 GUI 由带有 BorderLayout 的外部 JFrame 组成，在 BorderLayout 的东侧我有一个带有 GridBagLayout 的 JPanel。我试图在 JPanel 中定位 4 个按钮(最终还有其他一些东西，但当它不起作用时我将其缩减为按钮)，并将它们的 gridx 和 gridy 值设置为将它们放入 2 行 2 列中。但是，由于某种原因它不起作用。它没有将按钮放在两行两列中，而是仅显示一个按钮 ( screenshot )。

这是我的代码:

private class SidePanel extends JPanel
{
    private GridLayout sidePaneLayout;

    private JButton startButton;
    private JButton quitButton;
    private JButton saveButton;
    private JButton loadButton;
    private ButtonHandler buttonHandler;

    private JLabel stardate;
    private JLabel condition;
    private JLabel position;
    private JLabel warpFactor;
    private JLabel energy;
    private JLabel torpedos;
    private JLabel shields;
    private JLabel klingonsLeft;

    private JPanel statusPanel;


    public SidePanel()
    {
        super();

        this.setLayout(new GridBagLayout());
        GridBagConstraints constraints = new GridBagConstraints();



        startButton = new JButton("New Game");
        constraints.gridx = 0;
        constraints.gridy = 0;
        this.add(startButton, constraints);

        quitButton = new JButton("Quit Game");
        constraints.gridx = 0;
        constraints.gridy = 1;
        this.add(startButton, constraints);

        saveButton = new JButton("Save Game");
        constraints.gridx = 1;
        constraints.gridy = 0;
        this.add(startButton, constraints);

        loadButton = new JButton("Load Game");
        constraints.gridx = 1;
        constraints.gridy = 1;
        this.add(startButton, constraints);


        /*Dimension buttonSize = new Dimension(155, 60);

        startButton.setPreferredSize(buttonSize);
        quitButton.setPreferredSize(buttonSize);
        saveButton.setPreferredSize(buttonSize);
        loadButton.setPreferredSize(buttonSize);*/

        stardate = new JLabel("Stardate: ");
        condition = new JLabel("Condition: ");
        position = new JLabel("Position: ");
        warpFactor = new JLabel ("Warp Factor: ");
        energy = new JLabel("Energy: ");
        torpedos = new JLabel("Torpedos: ");
        shields = new JLabel("Shields: ");
        klingonsLeft = new JLabel("Klingons Left: ");

        statusPanel = new JPanel(new GridLayout(0, 2));





        statusPanel.add(stardate);
        statusPanel.add(condition);
        statusPanel.add(position);
        statusPanel.add(warpFactor);
        statusPanel.add(energy);
        statusPanel.add(torpedos);
        statusPanel.add(shields);
        statusPanel.add(klingonsLeft);

        constraints.gridx = 0;
        constraints.gridy = 2;
        //this.add(statusPanel, constraints);
    }

知道为什么这不起作用吗？我在独立的 JFrame 中使用 GridBagLayout 做了一些其他测试，它们都有效。但是当我尝试在该程序的内部 JPanel 中使用它时，它失败了。

Answer 1

您添加了 startButton 按钮 4 次，这就是它只显示一次的原因。

 this.add(startButton, constraints);

<小时/>

现在经过一些修正后，如下所示。

constraints.insets=new Insets(5, 5, 5, 5);// add top, left, bottom, right insets
...
constraints.gridx = 0;
constraints.gridy = 2;
constraints.gridwidth=2; // span two column
this.add(statusPanel, constraints);