java - (Java) 在 JPanel 的二维数组上使用 GridLayout(可能是 GridBagLayout)

Question

我正在尝试制作一个允许用户通过鼠标交互更改 JPanel 颜色的程序。我已经启动并运行了 JPanel 阵列 (5x5)，但它们会扩展以适应整个主面板，无论大小如何。关于如何为它们提供标准尺寸以使它们不会填满整个窗口并很好地适合中间的任何想法？

我被告知我可能必须为此使用 GridBagLayout 而不是 GridLayout，但我实际上没有使用该方法的经验，而且只是第一次听到这个名字，所以任何帮助也是一流的.

public void gridInit() {
        cell = new JPanel [x][x];
        setLayout(new GridLayout(5,5));
        for (int i = 0; i < x; i ++) {
            for (int j = 0; j < x; j ++) {
                cell [i][j] = new JPanel();
                cell [i][j].setBackground(new Color(i*40, j*30, 10));
                cell [i][j].setBorder(loweredetched);
                add(cell [i][j]);           
        }

编辑:我刚刚意识到这是我的第一篇文章，与修复错误无关，这可能是向前迈出的一步:)

Answer 1

将您的单元格放入 GridLayout - 使用创建的 JPanel 来保存它们，然后使用适合您的 GUI 的任何布局将那个 JPanel 添加到主 JPanel。请理解，您可以根据需要嵌套 JPanel，每个 JPanel 使用自己的布局管理器，从而允许使用简单的布局管理器来创建复杂的布局。

例如，

import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.*;

@SuppressWarnings("serial")
public class ColorGrid extends JPanel {
   private static final int PREF_W = 750;
   private static final int PREF_H = 550;
   private static final int GRID_ROWS = 5;
   private static final int GRID_COLS = 5;

   public ColorGrid() {
      JPanel gridPanel = new JPanel(new GridLayout(GRID_ROWS, GRID_COLS));
      for (int row = 0; row < GRID_ROWS; row++) {
         for (int col = 0; col < GRID_COLS; col++) {
            gridPanel.add(new ColorGridCell(row, col));
         }
      }

      setLayout(new GridBagLayout()); // to center component added
      add(gridPanel);
   }

   @Override
   public Dimension getPreferredSize() {
      return new Dimension(PREF_W, PREF_H);
   }

   private static void createAndShowGui() {
      ColorGrid mainPanel = new ColorGrid();

      JFrame frame = new JFrame("ColorGrid");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

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

@SuppressWarnings("serial")
class ColorGridCell extends JPanel {
   private static final int PREF_W = 100;
   private static final int PREF_H = 75;
   private final static Color[] COLORS = { Color.red, Color.orange,
         Color.yellow, Color.green, Color.blue, Color.cyan, Color.darkGray,
         Color.magenta, Color.pink };
   private int colorIndex = (int) (Math.random() * COLORS.length);
   private int row;
   private int col;

   public ColorGridCell(int row, int col) {
      this.row = row;
      this.col = col;
      setBackground(COLORS[colorIndex]);

      addMouseListener(new MouseAdapter() {
         @Override
         public void mousePressed(MouseEvent e) {
            colorIndex++;
            colorIndex %= COLORS.length;
            setBackground(COLORS[colorIndex]);
         }
      });
   }

   @Override
   public Dimension getPreferredSize() {
      return new Dimension(PREF_W, PREF_H);
   }

   public int getRow() {
      return row;
   }

   public int getCol() {
      return col;
   }
}