Question

好的，所以我正在搞乱GridBagLayout以掌握它。我想用它来在JFrame中布局JPanels，但是这些单独的面板将使用不同的布局管理器，GridBagLayout可能不适合。

但我有一个问题。如果我没有向面板添加任何内容，则所有比例都完美地完成，如下例所示：

public class RealMess extends JFrame{

private JPanel panel;

public RealMess(){
    initUI();
}

public final void initUI(){

    Dimension screensize = Toolkit.getDefaultToolkit().getScreenSize();
    int width = (int) screensize.getWidth();
    int height = (int) screensize.getHeight();

    panel = new JPanel();
    panel.setLayout(new GridBagLayout());



    JPanel left = new JPanel();
    left.setBackground(Color.GREEN);

    JPanel centre = new JPanel();
    centre.setBackground(Color.PINK);

    JPanel right = new JPanel();
    right.setBackground(Color.CYAN);

    JPanel leftBottom = new JPanel();
    leftBottom.setBackground(Color.LIGHT_GRAY);
    leftBottom.setLayout(new FlowLayout(0));



    JPanel bottom = new JPanel();
    bottom.setBackground(Color.MAGENTA);

    GridBagConstraints gbc = new GridBagConstraints();

    gbc.weightx = 0.11;
    gbc.weighty = 0.9;
    gbc.gridwidth = 1;
    gbc.gridheight = 1;
    gbc.anchor = GridBagConstraints.FIRST_LINE_START;
    gbc.gridx = 0;
    gbc.gridy = 0;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(left, gbc);

    gbc.weightx = 0.11;
    gbc.weighty = 0.1;
    gbc.anchor = GridBagConstraints.LAST_LINE_START;
    gbc.gridx = 0;
    gbc.gridy = 1;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(leftBottom, gbc);

    gbc.weightx = 0.78;
    gbc.weighty = 0.9;
    gbc.anchor = GridBagConstraints.PAGE_START;
    gbc.gridx = 1;
    gbc.gridy = 0;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(centre, gbc);

    gbc.weightx = 0.78;
    gbc.weighty = 0.1;
    gbc.anchor = GridBagConstraints.PAGE_END;
    gbc.gridx = 1;
    gbc.gridy = 1;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(bottom, gbc);

    gbc.weightx = 0.11;
    gbc.weighty = 1;
    gbc.anchor = GridBagConstraints.FIRST_LINE_END;
    gbc.gridx = 2;
    gbc.gridy = 0;
    gbc.gridheight = 2;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(right, gbc);

    add(panel);

    setTitle("Jack");
    setLocationRelativeTo(null);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setExtendedState(MAXIMIZED_BOTH);
}

public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable(){
        public void run(){
            RealMess rm = new RealMess();
            rm.setVisible(true);
        }
    });

}

}

我知道我不必要地重新定义了一些GridBagConstraints，但我不想错过任何东西。

无论如何，当我向任何面板添加按钮时，我的问题就出现了。像这样：

public class RealMess extends JFrame{

private JPanel panel;

public RealMess(){
    initUI();
}

public final void initUI(){

    Dimension screensize = Toolkit.getDefaultToolkit().getScreenSize();
    int width = (int) screensize.getWidth();
    int height = (int) screensize.getHeight();

    panel = new JPanel();
    panel.setLayout(new GridBagLayout());

    JPanel left = new JPanel();
    left.setBackground(Color.GREEN);

    JPanel centre = new JPanel();
    centre.setBackground(Color.PINK);

    JPanel right = new JPanel();
    right.setBackground(Color.CYAN);

    JPanel leftBottom = new JPanel();
    leftBottom.setBackground(Color.LIGHT_GRAY);
    leftBottom.setLayout(new FlowLayout(0));

    JButton rewind = new JButton("1");      
    rewind.setPreferredSize(new Dimension(50, 25));

    leftBottom.add(rewind);

    JPanel bottom = new JPanel();
    bottom.setBackground(Color.MAGENTA);

    GridBagConstraints gbc = new GridBagConstraints();

    gbc.weightx = 0.11;
    gbc.weighty = 0.9;
    gbc.gridwidth = 1;
    gbc.gridheight = 1;
    gbc.anchor = GridBagConstraints.FIRST_LINE_START;
    gbc.gridx = 0;
    gbc.gridy = 0;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(left, gbc);

    gbc.weightx = 0.11;
    gbc.weighty = 0.1;
    gbc.anchor = GridBagConstraints.LAST_LINE_START;
    gbc.gridx = 0;
    gbc.gridy = 1;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(leftBottom, gbc);

    gbc.weightx = 0.78;
    gbc.weighty = 0.9;
    gbc.anchor = GridBagConstraints.PAGE_START;
    gbc.gridx = 1;
    gbc.gridy = 0;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(centre, gbc);

    gbc.weightx = 0.78;
    gbc.weighty = 0.1;
    gbc.anchor = GridBagConstraints.PAGE_END;
    gbc.gridx = 1;
    gbc.gridy = 1;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(bottom, gbc);

    gbc.weightx = 0.11;
    gbc.weighty = 1;
    gbc.anchor = GridBagConstraints.FIRST_LINE_END;
    gbc.gridx = 2;
    gbc.gridy = 0;
    gbc.gridheight = 2;
    gbc.fill = GridBagConstraints.BOTH;

    panel.add(right, gbc);

    add(panel);

    setTitle("Jack");
    setLocationRelativeTo(null);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setExtendedState(MAXIMIZED_BOTH);
}

public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable(){
        public void run(){
            RealMess rm = new RealMess();
            rm.setVisible(true);
        }
    });

}

}

bottomLeft面板变得更大，因此网格方块的大小与之相关。

在第一个例子中，所有内容都占据窗口宽度或高度的百分比：

gbc.weightx

和

gbc.weighty

这样做可以很容易地使一切都正确。

是否有解决方法允许我强制仅通过重量值影响面板尺寸？

Answer 1

weightx和weighty显示基础组件未请求的空间的比例分配。例如，如果您有一个标签和一个水平方向的文本字段，您可能希望标签根据列中的最大标签采取固定数量的间距，并将空间的其余部分转到文本字段。将所有权重x分配给文本字段，这正是发生的事情。该标签的重量为零，但不会被压缩到零尺寸，因为只有多余的空间由重量决定。空面板的最小尺寸为零，因此所有空间都被视为额外空间。

如果要强制布局按照您的描述工作，则需要将子面板的JPanel扩展到GridBagLayout以了解其内容。如果你开始制作小于最小值的东西，这可能会让你陷入困境。

Java，当使用GridBagLayout布局面板时，向面板添加按钮会改变尺寸，我该如何防止这种情况？

1 个答案: