Java 的swing.GroupLayout布局管理器的使用方法和实例（转）

 The following builds a panel consisting of two labels in one column, followed by two textfields in the next column:

   JComponent panel = ...;
   GroupLayout layout = new GroupLayout(panel);
   panel.setLayout(layout);
 
   // Turn on automatically adding gaps between components
   layout.setAutoCreateGaps(true);
 
   // Turn on automatically creating gaps between components that touch
   // the edge of the container and the container.
   layout.setAutoCreateContainerGaps(true);
 
   // Create a sequential group for the horizontal axis.
 
   GroupLayout.SequentialGroup hGroup = layout.createSequentialGroup();
 
   // The sequential group in turn contains two parallel groups.
   // One parallel group contains the labels, the other the text fields.
   // Putting the labels in a parallel group along the horizontal axis
   // positions them at the same x location.
   //
   // Variable indentation is used to reinforce the level of grouping.
   hGroup.addGroup(layout.createParallelGroup().
            addComponent(label1).addComponent(label2));
   hGroup.addGroup(layout.createParallelGroup().
            addComponent(tf1).addComponent(tf2));
   layout.setHorizontalGroup(hGroup);
   
   // Create a sequential group for the vertical axis.
   GroupLayout.SequentialGroup vGroup = layout.createSequentialGroup();
 
   // The sequential group contains two parallel groups that align
   // the contents along the baseline. The first parallel group contains
   // the first label and text field, and the second parallel group contains
   // the second label and text field. By using a sequential group
   // the labels and text fields are positioned vertically after one another.
   vGroup.addGroup(layout.createParallelGroup(Alignment.BASELINE).
            addComponent(label1).addComponent(tf1));
   vGroup.addGroup(layout.createParallelGroup(Alignment.BASELINE).
            addComponent(label2).addComponent(tf2));
   layout.setVerticalGroup(vGroup);

GroupLayout 是一个 LayoutManager，它将组件按层次分组，以决定它们在 Container 中的位置。GroupLayout 主要供生成器使用，但也可以手工编码。分组由 Group 类的实例来完成。GroupLayout 支持两种组。串行组 (sequential group) 按顺序一个接一个地放置其子元素。并行组 (parallel group) 能够以四种方式对齐其子元素。

每个组可以包含任意数量的元素，其中元素有 Group、Component 或间隙 (gap)。间隙可被视为一个具有最小大小、首选大小和最大大小的不可见组件。此外，GroupLayout 还支持其值取自 LayoutStyle 的首选间隙。

GroupLayout是一个很重要的是额布局管理器，在jdk 1.6才加入，配合其它的管理器可以实现很好的界面。

GroupLayout必须要设置它的GroupLayout.setHorizontalGroup和GroupLayout.setVerticalGroup。

GroupLayout.setHorizontalGroup是指按照水平来确定，下面例子“账号”和“密码”是一个级别的，其它的组件也是一个级别的。详情请看代码

GroupLayout.setVerticalGroup。是按照垂直来确定的。他们的级别是按照Group去设置组件的优先级别，级别越高就显示越上面。

GroupLayout.setHorizontalGroup(SequentialGroup(ParallelGroup(component)));

大概就是按照这个顺序去添加,当然不是就这么简单设置，多个component添加到ParallelGroup，然后多个ParallelGroup添加到SequentialGroup里面，

然后就设置到GroupLayout

下面的实例，设置GroupLayout.setHorizontalGroup，就是把2和4添加到一个ParallelGroup.addComponent(component)，其它1,3,5,6,7,8添加到另一个ParallelGroup，然后把这两个ParallelGroup按照顺序添加到SequentialGroup.addGrou(ParallelGroup);

import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPasswordField;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
public class MyFrame extends javax.swing.JFrame {
    public static void main(String[] args) {
        MyFrame f = new MyFrame();
    }

    JLabel label1;
    JLabel label2;
    JLabel label3;
    JTextField tf;
    JPasswordField psf;
    JRadioButton rb1;
    JRadioButton rb2;

    JButton bt1;
    JButton bt2;

    public MyFrame() {
        this.setVisible(true);
        this.setSize(250, 220);
        this.setVisible(true);
        this.setLocation(400, 200);

        label1 = new JLabel("快捷登陆");
        label2 = new JLabel("账号：");
        label3 = new JLabel("密码：");
        tf = new JTextField();
        psf = new JPasswordField();
        rb1 = new JRadioButton("记住密码");
        rb2 = new JRadioButton("自动登陆");
        bt1 = new JButton("登陆");
        // 为指定的 Container 创建 GroupLayout
        GroupLayout layout = new GroupLayout(this.getContentPane());
        this.getContentPane().setLayout(layout);
        //创建GroupLayout的水平连续组，，越先加入的ParallelGroup，优先级级别越高。
        GroupLayout.SequentialGroup hGroup = layout.createSequentialGroup();
        hGroup.addGap(5);//添加间隔
        hGroup.addGroup(layout.createParallelGroup().addComponent(label2)
                .addComponent(label3));
        hGroup.addGap(5);
        hGroup.addGroup(layout.createParallelGroup().addComponent(label1)
                .addComponent(psf).addComponent(rb1).addComponent(rb2)
                .addComponent(tf).addComponent(bt1));
        hGroup.addGap(5);
        layout.setHorizontalGroup(hGroup);
        //创建GroupLayout的垂直连续组，，越先加入的ParallelGroup，优先级级别越高。
        GroupLayout.SequentialGroup vGroup = layout.createSequentialGroup();
        vGroup.addGap(10);
        vGroup.addGroup(layout.createParallelGroup().addComponent(label1));
        vGroup.addGap(10);
        vGroup.addGroup(layout.createParallelGroup().addComponent(label2)
                .addComponent(tf));
        vGroup.addGap(5);
        vGroup.addGroup(layout.createParallelGroup().addComponent(label3)
                .addComponent(psf));
        vGroup.addGroup(layout.createParallelGroup().addComponent(rb1));

        vGroup.addGroup(layout.createParallelGroup().addComponent(rb2));
        vGroup.addGroup(layout.createParallelGroup(Alignment.TRAILING)
                .addComponent(bt1));
        vGroup.addGap(10);
        //设置垂直组
        layout.setVerticalGroup(vGroup);
    }
}

http://www.cnblogs.com/taoweiji/archive/2012/12/10/2812221.html

Exception in thread "main" java.lang.IllegalStateException: javax.swing.JButton
    [..]
    is not attached to a vertical group

Add a vertical group and add the components to it.

From the JavaDocs:

GroupLayout treats each axis independently. That is, there is a group representing the horizontal axis, and a group representing the vertical axis. The horizontal group is responsible for determining the minimum, preferred and maximum size along the horizontal axis as well as setting the x and width of the components contained in it. The vertical group is responsible for determining the minimum, preferred and maximum size along the vertical axis as well as setting the y and height of the components contained in it. Each Component must exist in both a horizontal and vertical group, otherwise an IllegalStateException is thrown during layout, or when the minimum, preferred or maximum size is requested.

http://stackoverflow.com/questions/10472044/regarding-group-layout 

GroupLayout gl_composite = new GroupLayout(composite);  
91.        gl_composite.setHorizontalGroup(gl_composite.createParallelGroup(  
92.                GroupLayout.LEADING).add(canvas, GroupLayout.DEFAULT_SIZE, 468,  
93.                Short.MAX_VALUE).add(  
94.                GroupLayout.TRAILING,  
95.                gl_composite.createSequentialGroup().addContainerGap(125,  
96.                        Short.MAX_VALUE).add(button_1).add(68).add(btnbutton)  
97.                        .add(131)));  
98.        gl_composite.setVerticalGroup(gl_composite.createParallelGroup(  
99.                GroupLayout.LEADING).add(  
100.                gl_composite.createSequentialGroup().add(canvas,  
101.                        GroupLayout.DEFAULT_SIZE, 479, Short.MAX_VALUE).add(48)  
102.                        .add(  
103.                                gl_composite.createParallelGroup(  
104.                                        GroupLayout.BASELINE).add(btnbutton)  
105.                                        .add(button_1)).add(81)));  

http://blog.csdn.net/captaingan/article/details/7086760