java - 如何使用 GridBagLayout 将组件放在右下角？

Question

我需要在 JPanel 中显示单个组件，并且我想始终将该组件保持在右下角。我试着用 GridBagLayout 来做:

val infoArea = new TextArea {
  text = "Hello!"
  border = Swing.EmptyBorder(30)
  background = Color.RED
  editable = false
}
val p = new JPanel
p.setLayout(new GridBagLayout)
val c = new GridBagConstraints
c.gridx = 0
c.gridy = 0
c.anchor = GridBagConstraints.LAST_LINE_END
p.add(infoArea.peer,c)
val f = new JFrame
f.setContentPane(p)
f.setVisible(true)

但由于某种原因文本区域位于中心:

我在这里做错了什么？

Answer 1

例如:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;

import javax.swing.*;

public class LayoutDemo {
   private static void createAndShowGui() {
      JLabel label = new JLabel("Hello");
      label.setOpaque(true);
      label.setBackground(Color.red);

      JPanel bottomPanel = new JPanel(new BorderLayout());
      bottomPanel.add(label, BorderLayout.LINE_END);

      JPanel mainPanel = new JPanel(new BorderLayout());
      mainPanel.add(bottomPanel, BorderLayout.PAGE_END);
      mainPanel.setPreferredSize(new Dimension(400, 400));


      JFrame frame = new JFrame("LayoutDemo");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}