JavaJPanel和GridBagLayout

Question

我想在JPanel中动态地放置按钮。为此，我选择将GridBagLayout应用于此面板（包含按钮的面板）

问题是我的按钮出现在面板中央，而我希望它们从上到下放置

这是我的密码：

void placerListeUsers(){

  jPanel49.setLayout(new GridBagLayout());
  //jPanel49 est le panel sur lequel je place mes boutons.
  //jPanel49 est placé dans une JScrollPane
  GridBagConstraints c = new GridBagConstraints();
  c.gridx = 0;
  c.fill = GridBagConstraints.HORIZONTAL;
  //c.anchor=GridBagConstraints.NORTH;

  c.weightx = 1;
  //c.weighty = 0;

  for (int i = 0; i < 5; i++) {
  c.gridwidth = GridBagConstraints.REMAINDER;
  c.gridy = i;
  jPanel49.add(new JButton("Super"), c);

}

他所生产的：

谢谢你帮我解决这个问题

Answer 1

the problem is that my buttons appear from the center of my panel while I would like them to be placed from top to bottom.

需要指定WebXY/Y约束，否则组件会聚集在中间。

阅读关于How to Use GridBagLayout的Swing教程。关于Specifying Constraints的部分将为您提供更多信息

在我看来，你只有垂直按钮。也许将GridLayout或BoxLayout添加到帧的BorderLayout.PAGE_START中会更容易

Answer 2

即使您没有按照要求提供MCVE。我试图为您的布局提供解决方案…；）

问题是，正如camickr已经提到的，在计算按钮大小后，您需要告诉GridBagLayout将面板的所有额外空间放在哪里：

• 锚定必须是网格约束。北方

• weight需要为添加到面板的最后一个按钮设置为1

  public static void main(String[] args) {
  JFrame frame = new JFrame();
  
  frame.addWindowListener(new WindowAdapter() {
      @Override
      public void windowClosing(WindowEvent e) {
          System.exit(0);
      }
  });
  Container content = frame.getContentPane();
  GridBagLayout layout = new GridBagLayout();
  JPanel panel = new JPanel(layout);
  GridBagConstraints c = new GridBagConstraints();
  c.gridx = 0;
  c.fill = GridBagConstraints.HORIZONTAL;
  c.anchor = GridBagConstraints.NORTH;
  c.weightx = 1;
  int buttonCount = 5;
  for (int i = 0; i < buttonCount; i++) {
      c.weighty = i == buttonCount - 1 ? 1 : 0;
      c.gridwidth = GridBagConstraints.REMAINDER;
      c.gridy = i;
      JButton button = new JButton("Super");
      panel.add(button, c);
  }
  content.add(new JScrollPane(panel));
  frame.pack();
  frame.setSize(400, 400);
  frame.setVisible(true);
  }