如何正确使用 GridLayout 在 JFrame 中定位元素？

Question

这就是我希望我的 JFrame 的样子：

________________________________________________________________________________
|Play                                                                     - 0 x |
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Score List:     | 
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Mario: 100      | 
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Luigi: 50       |        
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Waluigi: 20     | 
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Wario: 10       |       
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                 | 
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                 |       
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                 | 
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                 |       
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                 | 
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                 |       
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                 | 
|%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                 |    
|Status: Ready!                                                       Score: 30 |
‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾

目前，每个元素的大小相同，基本上只是将中间和顶部/底部分开。 Play 是 Frame 的标题，%s 表示用户可以在其中玩游戏的 JPanel。 'Status: Ready' 是一个 JLabel，'Score: 30' 也是如此。分数列表是一个 JTextArea。

那么，我该如何设置这些元素的大小和位置呢？到目前为止，我会给你我的代码，也许你能告诉我哪里出错了。

this.add(playPanel);
this.add(scoreArea);
this.add(statusLabel);
this.add(scoreLabel);
this.setLayout(new GridLayout(2,2));

Answer 1

GridBagLayout 应该是您的完美解决方案。它支持遵循组件的首选大小和巧妙地使用GridBagConstraints。使用GridBagLayout's GridBagConstraint 属性：

1. gridx, gridy：您的组件将被放置在grid(X, Y)。在添加任何组件之前，您可以使用这些属性指定网格，将添加到哪个组件。
2. anchor：FIRST_LINE_START, PAGE_START, FIRST_LINE_END, LINE_START, LINE_END 等用于在 每个网格的可用空间。
3. weightx, weighty：对于it is the center，标签weightx 和weighty 被指定为响应重新调整width 和height 中的容器大小。对于score list 标签，仅指定weighty 以响应仅在height 中重新调整容器大小。
4. gridwidth：对于it is the center 标签，此属性指定为2 以获取两个网格。
5. fill：指定为BOTH 用于it is the center 标签以填充可用显示的宽度和高度。并且此属性设置为VERTICAL 用于score list 标签以填充显示区域的高度。

这是一个为您打造的 Demo，让您一目了然：

没有真正编码为标准（不应该通过setPreferredSize() 设置首选大小）但我认为它符合演示目的。

源代码：

import java.awt.*;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.HeadlessException;
import java.awt.Insets;
import javax.swing.*;
import javax.swing.SwingUtilities;

/**
 *
 * @author Rashed
 */
 class GridBagLayoutDemo extends JFrame{


    public JLabel createLabel(String txt, int width, int height, Color color)
    {
        JLabel label = new JLabel(txt);
        label.setOpaque(true);
        label.setBackground(color);
        label.setPreferredSize(new Dimension(width, height));
        return label;
    }

    public GridBagLayoutDemo() throws HeadlessException {
       setSize(400,400);
       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

       JPanel panel = new JPanel(new java.awt.GridBagLayout());
       GridBagConstraints labCnst = new GridBagConstraints();

       labCnst.fill = GridBagConstraints.NONE;
       labCnst.insets = new Insets(3, 3, 3, 3);
       labCnst.anchor = GridBagConstraints.FIRST_LINE_START;
       labCnst.gridx  = 0;
       labCnst.gridy = 0;
       panel.add(createLabel("play", 100, 30, new Color(0x359DBD)), labCnst);

      // labCnst.anchor = GridBagConstraints.LAST_LINE_START;
       labCnst.gridx  = 0;
       labCnst.gridy = 2;
       panel.add(createLabel("Status: Ready!", 100, 30, new Color(0x359DBD)), labCnst);

       labCnst.anchor = GridBagConstraints.FIRST_LINE_END;
       labCnst.gridx  = 2;
       labCnst.gridy = 0;
       panel.add(createLabel("-0x", 100, 30, new Color(0x359DBD)), labCnst);

       labCnst.anchor = GridBagConstraints.LAST_LINE_END;
       labCnst.gridx  = 2;
       labCnst.gridy = 2;
       panel.add(createLabel("score:30", 100, 30, new Color(0x359DBD)), labCnst);


       labCnst.anchor = GridBagConstraints.LINE_START;
       labCnst.fill = GridBagConstraints.VERTICAL;
       labCnst.gridx  = 2;
       labCnst.gridy = 1;
       labCnst.gridwidth = 1;

       labCnst.weightx = 0.7;
       labCnst.weighty = 0.7;
       panel.add(createLabel("ScoreList", 100, 200, new Color(0xFFAA00)), labCnst);


       labCnst.gridx = 0;
       labCnst.gridy = 1;
       //labCnst.anchor = GridBagConstraints.LIN;
       labCnst.gridwidth = 2;

       labCnst.weightx = 0.8;
       labCnst.weighty = 0.8;
       labCnst.fill = GridBagConstraints.BOTH;
       panel.add(createLabel("It is the center", 200, 200, new Color(0xFFD47E)), labCnst);

       //labCnst.anchor = GridBagConstraints.LINE_END;


       add(panel);

    }


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

            @Override
            public void run() {
                new GridBagLayoutDemo().setVisible(true);
            }
        });
    }
}

Answer 2

您可能想查看Gridbaglayout。 它可能更适合您的需求。