Swing布局管理器介绍

不念不忘少年蓝@ 2021-12-17 14:21 287阅读 0赞

创作品，允许转载，转载时请务必以超链接形式标明文章  [原始出处][Link 1] 、作者信息和本声明。否则将追究法律责任。 [http://zhangjunhd.blog.51cto.com/113473/128174][Link 1]

当选择使用JPanel和顶层容器的content pane时，需要考虑布局管理。JPanel缺省是初始化一个FlowLayout，而content pane缺省是初始化一个BorderLayout。

下面将分别介绍几种最常用的布局管理器：FlowLayout、BorderLayout、BoxLayout、CardLayout、GridLayout和GridBagLayout。

**代码演示**

每一个布局管理器都会有一个代码演示，xxxLayoutDemo.java（见附件）。这些文件主要有三个方法组成：

addComponentsToPane()提供布局逻辑（依据不同的布局管理器和UI内容）。

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>public</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;addComponentsToPane(Container pane) {。。。} 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

createAndShowGUI()实例化一个JFrame，通过它的ContentPane加载布局逻辑内容。

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>private</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;createAndShowGUI() { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;// Create and set up the window. 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JFrame frame =&nbsp; 
     <strong>new</strong>&nbsp;JFrame("FlowLayoutDemo"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;frame.setDefaultCloseOperation(JFrame. 
     <em>EXIT_ON_CLOSE</em>); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;// Set up the content pane. 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <em>addComponentsToPane</em>(frame.getContentPane()); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;// Display the window. 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;frame.pack(); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;frame.setVisible( 
     <strong>true</strong>); 
    </div> 
    <div>
      } 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

main()程序入口，单独起一个线程，实例化UI。

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>public</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;main(String[] args) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;javax.swing.SwingUtilities. 
     <em>invokeLater</em>( 
     <strong>new</strong>&nbsp;Runnable() { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
     <strong>public</strong>&nbsp; 
     <strong>void</strong>&nbsp;run() { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
     <em>createAndShowGUI</em>(); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;} 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;}); 
    </div> 
    <div>
      } 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

**FlowLayout**

FlowLayout类是最简单的布局管理器。它按照和页面上排列单词的类似方式来安排组件----从左到右，直至没有多余的空间，然后转到下一行。

效果：

内容面板代码：

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>public</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;addComponentsToPane(Container pane) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.setLayout( 
     <strong>new</strong>&nbsp;FlowLayout()); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add( 
     <strong>new</strong>&nbsp;JButton("Button 1")); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add( 
     <strong>new</strong>&nbsp;JButton("Button 2")); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add( 
     <strong>new</strong>&nbsp;JButton("Button 3")); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add( 
     <strong>new</strong>&nbsp;JButton("Long-Named Button 4")); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add( 
     <strong>new</strong>&nbsp;JButton("5")); 
    </div> 
    <div>
      } 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

**BorderLayout**

一个BorderLayout对象将界面分成五大区域，分别用BorderLayout类的静态常量指定：

\-PAGE\_START

\-PAGE\_END

\-LINE\_START

\-LINE\_END

\-CENTER

效果：

内容面板代码：

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>public</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;addComponentsToPane(Container pane) {&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JButton button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("Button 1 (PAGE_START)"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, BorderLayout. 
     <em>PAGE_START</em>);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("Button 2 (CENTER)"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button.setPreferredSize( 
     <strong>new</strong>&nbsp;Dimension(200, 100)); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, BorderLayout. 
     <em>CENTER</em>);&nbsp;&nbsp;&nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("Button 3 (LINE_START)"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, BorderLayout. 
     <em>LINE_START</em>);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("Long-Named Button 4 (PAGE_END)"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, BorderLayout. 
     <em>PAGE_END</em>);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("5 (LINE_END)"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, BorderLayout. 
     <em>LINE_END</em>); 
    </div> 
    <div>
      } 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

**BoxLayout**

BoxLayout可以将组件由上至下或由左至右依次加入当前面板。

效果：

内容面板代码：

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>public</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;addComponentsToPane(Container pane) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JPanel xPanel =&nbsp; 
     <strong>new</strong>&nbsp;JPanel(); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;xPanel.setLayout( 
     <strong>new</strong>&nbsp;BoxLayout(xPanel, BoxLayout. 
     <em>X_AXIS</em>)); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <em>addButtons</em>(xPanel); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JPanel yPanel =&nbsp; 
     <strong>new</strong>&nbsp;JPanel(); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;yPanel.setLayout( 
     <strong>new</strong>&nbsp;BoxLayout(yPanel, BoxLayout. 
     <em>Y_AXIS</em>)); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <em>addButtons</em>(yPanel); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(yPanel, BorderLayout. 
     <em>PAGE_START</em>); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(xPanel, BorderLayout. 
     <em>PAGE_END</em>); 
    </div> 
    <div>
      } 
    </div> 
    <div>
      &nbsp; 
    </div> 
    <div> 
     <strong>private</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;addAButton(String text, Container container) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JButton button =&nbsp; 
     <strong>new</strong>&nbsp;JButton(text); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button.setAlignmentX(Component. 
     <em>CENTER_ALIGNMENT</em>); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;container.add(button); 
    </div> 
    <div>
      } 
    </div> 
    <div>
      &nbsp; 
    </div> 
    <div> 
     <strong>private</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;addButtons(Container container) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <em>addAButton</em>("Button 1", container); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <em>addAButton</em>("Button 2", container); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <em>addAButton</em>("Button 3", container); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <em>addAButton</em>("Long-Named Button 4", container); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <em>addAButton</em>("5", container); 
    </div> 
    <div>
      } 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

**CardLayout**

卡片布局和其他布局不同，因为它隐藏了一些组件。卡片布局就是一组容器或者组件，它们一次仅仅显是一个，组中的每个容器称为卡片。

效果：

内容面板代码：

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>public</strong>&nbsp; 
     <strong>void</strong>&nbsp;addComponentToPane(Container pane) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <strong>final</strong>&nbsp;JPanel contentPanel =&nbsp; 
     <strong>new</strong>&nbsp;JPanel(); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JPanel controlPanel =&nbsp; 
     <strong>new</strong>&nbsp;JPanel(); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <strong>final</strong>&nbsp;CardLayout cardLayout= 
     <strong>new</strong>&nbsp;CardLayout();; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.setLayout( 
     <strong>new</strong>&nbsp;BorderLayout()); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(contentPanel, BorderLayout. 
     <em>CENTER</em>); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(controlPanel, BorderLayout. 
     <em>PAGE_END</em>); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;controlPanel.setLayout( 
     <strong>new</strong>&nbsp;FlowLayout()); 
    </div> 
    <div>
      &nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JButton[] b =&nbsp; 
     <strong>new</strong>&nbsp;JButton[10]; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <strong>for</strong>&nbsp;( 
     <strong>int</strong>&nbsp;i = 0; i &lt; 10; i++) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b[i] =&nbsp; 
     <strong>new</strong>&nbsp;JButton("No."&nbsp;+ i); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;contentPanel.add(b[i]); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;} 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;contentPanel.setLayout(cardLayout); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JButton nextButton =&nbsp; 
     <strong>new</strong>&nbsp;JButton("next"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;nextButton.addActionListener( 
     <strong>new</strong>&nbsp;ActionListener(){ 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
     <strong>public</strong>&nbsp; 
     <strong>void</strong>&nbsp;actionPerformed(ActionEvent e) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;cardLayout.next(contentPanel); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}}); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;controlPanel.add(nextButton); 
    </div> 
    <div>
      } 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

**GridLayout**

GridLayout让你建立一个组件表格，并且当组件加入时，会依序又左至右，由上至下填充到每个格子，它不能由你指定想放那个格子就放那个格子

效果：

内容面板代码：

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>public</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;addComponentsToPane(Container pane) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JButton[] buttons =&nbsp; 
     <strong>new</strong>&nbsp;JButton[9]; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.setLayout( 
     <strong>new</strong>&nbsp;GridLayout(3, 3)); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp; 
     <strong>for</strong>&nbsp;( 
     <strong>int</strong>&nbsp;i = 0; i &lt; buttons.length; i++) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;buttons[i] =&nbsp; 
     <strong>new</strong>&nbsp;JButton(i +&nbsp;""); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;pane.add(buttons[i]); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;} 
    </div> 
    <div>
      } 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

**GridBagLayout**

GridBagLayout是所有AWT布局管理器当中最复杂的，同时他的功能也是最强大的。GridBagLayout同GridLayout一样，在容器中以网格形式来管理组件。但GridBagLayout功能要来得强大得多。

1、GridBagLayout管理的所有行和列都可以是大小不同的；

2、GridLayout把每个组件限制到一个单元格，而GridBagLayout并不这样：组件在容器中可以占据任意大小的矩形区域。

GridBagLayout通常由一个专用类来对他布局行为进行约束，该类叫GridBagConstraints。其中有11个公有成员变量，GridBagConstraints可以从这11个方面来进行控制和操纵。这些内容是：

1、gridx—组件的横向坐标；

2、girdy—组件的纵向坐标；

3、gridwidth—组件的横向宽度，也就是指组件占用的列数；

4、gridheight—组件的纵向长度，也就是指组件占用的行数；

5、weightx—指行的权重，告诉布局管理器如何分配额外的水平空间；

6、weighty—指列的权重，告诉布局管理器如何分配额外的垂直空间；

7、anchor—当组件小于其显示区域时使用此字段；

8、fill—如果显示区域比组件的区域大的时候，可以用来控制组件的行为。控制组件是垂直填充，还是水平填充，或者两个方向一起填充；

9、insets—指组件与表格空间四周边缘的空白区域的大小；

10、ipadx— 组件间的横向间距，组件的宽度就是这个组件的最小宽度加上ipadx值；

11、ipady— 组件间的纵向间距，组件的高度就是这个组件的最小高度加上ipady值。

说明：

1、gridx，gridy：其实就是组件行列的设置，注意都是从0开始的，比如 gridx=0，gridy=1时放在0行1列；

2、gridwidth，gridheight：默认值为1；GridBagConstraints.REMAINDER常量，代表此组件为此行或此列的最后一个组件，会占据所有剩余的空间；

3、weightx，weighty：当窗口变大时，设置各组件跟着变大的比例。比如组件A的weightx=0.5，组件B的weightx=1，那么窗口X轴变大时剩余的空间就会以1：2的比例分配给组件A和B；

4、anchor：当组件空间大于组件本身时，要将组件置于何处。 有CENTER（默认值）、NORTH、NORTHEAST、EAST、SOUTHEAST、WEST、NORTHWEST选择。

5、insets：设置组件之间彼此的间距。它有四个参数，分别是上，左，下，右，默认为（0，0，0，0）。

效果：

内容面板代码：

<table> 
 <tbody> 
  <tr> 
   <td> 
    <div> 
     <strong>public</strong>&nbsp; 
     <strong>static</strong>&nbsp; 
     <strong>void</strong>&nbsp;addComponentsToPane(Container pane) { 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;JButton button; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.setLayout( 
     <strong>new</strong>&nbsp;GridBagLayout()); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;GridBagConstraints c =&nbsp; 
     <strong>new</strong>&nbsp;GridBagConstraints(); 
    </div> 
    <div>
      &nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("Button 1"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.fill&nbsp;= GridBagConstraints. 
     <em>HORIZONTAL</em>; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridx&nbsp;= 0; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridy&nbsp;= 0; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, c); 
    </div> 
    <div>
      &nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("Button 2"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.fill&nbsp;= GridBagConstraints. 
     <em>HORIZONTAL</em>; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.weightx&nbsp;= 0.5; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridx&nbsp;= 1; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridy&nbsp;= 0; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, c); 
    </div> 
    <div>
      &nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("Button 3"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.fill&nbsp;= GridBagConstraints. 
     <em>HORIZONTAL</em>; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.weightx&nbsp;= 0.5; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridx&nbsp;= 2; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridy&nbsp;= 0; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, c); 
    </div> 
    <div>
      &nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("Long-Named Button 4"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.fill&nbsp;= GridBagConstraints. 
     <em>HORIZONTAL</em>; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.ipady&nbsp;= 40;&nbsp;// make this component tall 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.weightx&nbsp;= 0.0; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridwidth&nbsp;= 3; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridx&nbsp;= 0; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridy&nbsp;= 1; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, c); 
    </div> 
    <div>
      &nbsp; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;button =&nbsp; 
     <strong>new</strong>&nbsp;JButton("5"); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.fill&nbsp;= GridBagConstraints. 
     <em>HORIZONTAL</em>; 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.ipady&nbsp;= 0;&nbsp;// reset to default 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.weighty&nbsp;= 1.0;&nbsp;// request any extra vertical space 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.anchor&nbsp;= GridBagConstraints. 
     <em>PAGE_END</em>;&nbsp;// bottom of space 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.insets&nbsp;=&nbsp; 
     <strong>new</strong>&nbsp;Insets(10, 0, 0, 0);&nbsp;// top padding 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridx&nbsp;= 1;&nbsp;// aligned with button 2 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridwidth&nbsp;= 2;&nbsp;// 2 columns wide 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;c.gridy&nbsp;= 2;&nbsp;// third row 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;pane.add(button, c); 
    </div> 
    <div>
      &nbsp;&nbsp;&nbsp;&nbsp;} 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

一个GardBagLayout布局的左右选择框，代码GridBagLayoutFrame.java见附件，效果：

本文出自 “[子 孑][Link 2]” 博客，请务必保留此出处[http://zhangjunhd.blog.51cto.com/113473/128174][Link 1]

转载于:https://www.cnblogs.com/kungfupanda/p/5995461.html

[Link 1]: http://zhangjunhd.blog.51cto.com/113473/128174
[Link 2]: http://zhangjunhd.blog.51cto.com/