Question

我正在尝试创建一个程序，允许用户通过鼠标交互来更改JPanels的颜色。我有一系列JPanels全部启动并运行（5x5）但它们扩展到适合整个主面板，无论大小。关于如何给它们一个标准尺寸的任何想法，以便它们不会填满整个窗口并且恰好适合中间？

我被告知我可能不得不使用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，所以任何帮助都会是类

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，而不是修复错误，这可能是向前迈出的一步：）

Answer 1

将您的单元格置于GridLayout中 - 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 JPanel添加到主JPanel。请理解您可以根据需要嵌套JPanel，每个都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。

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;
   }
}

（Java）在JPanel的2D数组上使用GridLayout（可能是GridBagLayout）

1 个答案: