摘自http://blog.csdn.net/qq_18989901/article/details/52403737

 GridBagLayout的用法

GridBagLayout是面板设计中最复杂的布局工具，当然用的好的话也是最方便的。

GridBagLayout其组件的摆放都是有GridBagConstraints控制的。可以将需要设计的界面划分成许多个纵横的小网格，每个网格里面最多放置一个组件，一个组件可以占用多个网格。

网格的定义是由gridx和gridy定义的，前者表示横坐标，后者表示纵坐标，坐标是从0开始，从整个面板的左上角开始算起，所以在上图中，按钮7所在的位置gridx=0，gridy=0;以此类推，后面所有的网格位置都可以这样定义；

但是图中网格的宽度和高度是由什么定义的呢？答案是gridwidth和gridheight，为1表示占用一个网格，为2表示占用两个网格，如上图中"+"的gridwidth=1，gridheight=2；

知道这两个，就可以大体把网格划分清楚，每一个的具体位置也就有了着落。有朋友会说，我也是这样写的，但是组件怎么就那么小呢？那是因为GridBaglayout里面还有一项参数weight，她控制着组件随着面板的变化自身的变化情况，默认情况下weightx=0,weighty=0，意思是组件大小固定，不管面板如何变，自身就那么大，但是如果想让组件随面板变化的话，可以设置weightx和weighty，设置为浮点数也行，其值代表着变化的大小，也就是你宽度设为2，高度设为1的话，拉大面板会使组件越变越宽。

这三个是比较重要的Constraints，另外，还有insets，其有四个参数，表示其上左下右和相邻组件的最小间隔；ipadx和ipady表示组件间距，默认是0（其和insets不同读者可以自己摸索一下）；fill参数表示当网格区域比组件大的伤害，组件是以何种方式填充区域，是全方位还是水平或竖直；anchor是区域比组件大时，组件应该显示在区域的哪个方位，西北还是东南；

测试1：

本文主要通过设计一个计算器界面的方式，来学习GridBagLayout的使用。最终的效果如下图所示：

下面是我实现面板显示部分的所有代码：

 package com.wst.bj;

 import java.awt.GridBagConstraints;

 import java.awt.GridBagLayout;

 import java.awt.Insets;

 import javax.swing.JButton;

 import javax.swing.JFrame;

 import javax.swing.JPanel;

 import javax.swing.JTextField;

 public class GridBagTest2 {

     private JFrame jframe = new JFrame();

     private JButton bt1 = new JButton("1");

     private JButton bt2 = new JButton("2");

     private JButton bt3 = new JButton("3");

     private JButton bt4 = new JButton("4");

     private JButton bt5 = new JButton("5");

     private JButton bt6 = new JButton("6");

     private JButton bt7 = new JButton("7");

     private JButton bt8 = new JButton("8");

     private JButton bt9 = new JButton("9");

     private JButton bt0 = new JButton("0");

     private JButton btdot = new JButton(".");

     private JButton btsignleft = new JButton("(");

     private JButton btsignright = new JButton(")");

     private JButton btp = new JButton("+");

     private JButton btm = new JButton("-");

     private JButton btmp = new JButton("*");

     private JButton btd = new JButton("/");

     private JButton bte = new JButton("=");

     private JButton bt = new JButton("00");

     private JButton btclear = new JButton("cl");

     private JTextField textField = new JTextField();

     public GridBagTest2() {

         init();

     }

     private void init()

     {

         FrameUtil.initFram(jframe, 300, 400);

         JPanel jpanel = createPanel();

         jframe.add(jpanel);

     }

     private JPanel createPanel(){

         JPanel panel = new JPanel();

         GridBagLayout gbl = new GridBagLayout();

         GridBagConstraints gbs = new GridBagConstraints();

         panel.setLayout(gbl);

         panel.add(bt7);panel.add(bt8);panel.add(bt9);panel.add(btp);

         panel.add(bt4);panel.add(bt5);panel.add(bt6);

 //      panel.add(bt1);panel.add(bt2);panel.add(bt9);panel.add(btp);

         panel.add(bt1);panel.add(bt2);panel.add(bt3);panel.add(btm);

         panel.add(bt0);panel.add(btdot);

         panel.add(btsignleft);panel.add(btsignright);panel.add(bte);panel.add(btmp);

         panel.add(btclear);panel.add(bt);                panel.add(btd);

         panel.add(textField);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=0;

         gbl.setConstraints(bt7, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=1;gbs.gridy=0;

         gbl.setConstraints(bt8, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=2;gbs.gridy=0;

         gbl.setConstraints(bt9, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=2;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=3;gbs.gridy=0;

         gbl.setConstraints(btp, gbs);    

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=1;

         gbl.setConstraints(bt4, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=1;gbs.gridy=1;

         gbl.setConstraints(bt5, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=2;gbs.gridy=1;

         gbl.setConstraints(bt6, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=2;

         gbl.setConstraints(bt1, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=1;gbs.gridy=2;

         gbl.setConstraints(bt2, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=2;gbs.gridy=2;

         gbl.setConstraints(bt3, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=2;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=3;gbs.gridy=2;

         gbl.setConstraints(btm, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=2;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=3;

         gbl.setConstraints(bt0, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=2;gbs.gridy=3;

         gbl.setConstraints(btdot, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=4;

         gbl.setConstraints(btsignleft, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=1;gbs.gridy=4;

         gbl.setConstraints(btsignright, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=2;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=2;gbs.gridy=4;

         gbl.setConstraints(bte, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=3;gbs.gridy=4;

         gbl.setConstraints(btmp, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=5;

         gbl.setConstraints(btclear, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=1;gbs.gridy=5;

         gbl.setConstraints(bt, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=3;gbs.gridy=5;

         gbl.setConstraints(btd, gbs);

         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=4;gbs.gridheight=3;

         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=6;

         gbl.setConstraints(textField, gbs);

         return panel;

     }

 }

测试2：

 package com.wst.bj;

 import java.awt.GridBagConstraints;

 import java.awt.GridBagLayout;

 import java.awt.Insets;

 import javax.swing.JButton;

 import javax.swing.JFrame;

 import javax.swing.JPanel;

 import javax.swing.JTextField;

 public class GridBagTest4 {

     private JFrame jframe = new JFrame();

     private JButton bt1 = new JButton("1");

     private JButton bt2 = new JButton("2");

     private JButton bt3 = new JButton("3");

     private JButton bt4 = new JButton("4");

     private JButton bt5 = new JButton("5");

     private JButton bt6 = new JButton("6");

     private JButton bt7 = new JButton("7");

     private JButton bt8 = new JButton("8");

     private JButton bt9 = new JButton("9");

     private JButton bt0 = new JButton("0");

     private JButton btdot = new JButton(".");

     private JButton btsignleft = new JButton("(");

     private JButton btsignright = new JButton(")");

     private JButton btp = new JButton("+");

     private JButton btm = new JButton("-");

     private JButton btmp = new JButton("*");

     private JButton btd = new JButton("/");

     private JButton bte = new JButton("=");

     private JButton bt = new JButton("00");

     private JButton btclear = new JButton("cl");

     private JTextField textField = new JTextField();

     public GridBagTest4() {

         init();

     }

     private void init()

     {

         FrameUtil.initFram(jframe, 300, 400);

         JPanel jpanel = createPanel();

         jframe.add(jpanel);

     }

     private JPanel createPanel(){

         JPanel panel = new JPanel();

         GridBagLayout gbl = new GridBagLayout();

         GridBagConstraints gbs = new GridBagConstraints();

         panel.setLayout(gbl);

         panel.add(bt7);panel.add(bt8);panel.add(bt9);panel.add(btp);

         panel.add(bt4);panel.add(bt5);panel.add(bt6);

         panel.add(bt1);panel.add(bt2);panel.add(bt3);panel.add(btm);

         panel.add(bt0);panel.add(btdot);

         panel.add(btsignleft);panel.add(btsignright);panel.add(bte);panel.add(btmp);

         panel.add(btclear);panel.add(bt);                panel.add(btd);

         panel.add(textField);

         gbs.fill=GridBagConstraints.NONE;

 //        gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.ipadx = 100;

 //        gbs.ipady = 100;

         gbs.anchor = GridBagConstraints.WEST;

         gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=0;

         gbl.setConstraints(bt7, gbs);

         gbs.fill=GridBagConstraints.NONE;

 //        gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.NORTHEAST;

         gbs.gridx=1;gbs.gridy=0;

         gbl.setConstraints(bt8, gbs);

         gbs.fill=GridBagConstraints.NONE;

 //        gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.SOUTH;

         gbs.gridx=2;gbs.gridy=0;

         gbl.setConstraints(bt9, gbs);

 //

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=2;

 ////        gbs.insets=new Insets(5, 5, 5, 5);

 ////        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=3;gbs.gridy=0;

         gbl.setConstraints(btp, gbs);

         // =====================================================

         gbs.fill=GridBagConstraints.VERTICAL;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.WEST;

         gbs.gridx=0;gbs.gridy=1;

         gbl.setConstraints(bt4, gbs);

 //

         gbs.fill=GridBagConstraints.VERTICAL;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.SOUTHEAST;

         gbs.gridx=1;gbs.gridy=1;

         gbl.setConstraints(bt5, gbs);

         gbs.fill=GridBagConstraints.VERTICAL;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.CENTER;

         gbs.gridx=2;gbs.gridy=1;

         gbl.setConstraints(bt6, gbs);

         // =====================================================

         gbs.fill=GridBagConstraints.HORIZONTAL;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.NORTH;

         gbs.gridx=0;gbs.gridy=2;

         gbl.setConstraints(bt1, gbs);

         gbs.fill=GridBagConstraints.HORIZONTAL;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.SOUTHEAST;

         gbs.gridx=1;gbs.gridy=2;

         gbl.setConstraints(bt2, gbs);

         gbs.fill=GridBagConstraints.HORIZONTAL;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.CENTER;

         gbs.gridx=2;gbs.gridy=2;

         gbl.setConstraints(bt3, gbs);

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=2;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=3;gbs.gridy=2;

         gbl.setConstraints(btm, gbs);

         // =====================================================

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=2;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=3;

         gbl.setConstraints(bt0, gbs);

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=2;gbs.gridy=3;

         gbl.setConstraints(btdot, gbs);

         // =====================================================

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=4;

         gbl.setConstraints(btsignleft, gbs);

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=1;

         gbs.insets=new Insets(7, 7, 2, 2);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=1;gbs.gridy=4;

         gbl.setConstraints(btsignright, gbs);

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=2;

         gbs.insets=new Insets(0, 0, 0, 0);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=2;gbs.gridy=4;

         gbl.setConstraints(bte, gbs);

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=3;gbs.gridy=4;

         gbl.setConstraints(btmp, gbs);

         // =====================================================

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

         gbs.weightx=0;gbs.weighty=0;

         gbs.gridx=0;gbs.gridy=5;

         gbl.setConstraints(btclear, gbs);

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=1;gbs.gridy=5;

         gbl.setConstraints(bt, gbs);

         gbs.fill=GridBagConstraints.NONE;

         gbs.gridwidth=1;gbs.gridheight=1;

 //        gbs.insets=new Insets(5, 5, 5, 5);

 //        gbs.weightx=1;gbs.weighty=1;

         gbs.anchor = GridBagConstraints.EAST;

         gbs.gridx=3;gbs.gridy=5;

         gbl.setConstraints(btd, gbs);

         // =====================================================

         gbs.fill=GridBagConstraints.BOTH;

         gbs.gridwidth=4;gbs.gridheight=3;

 //        gbs.insets=new Insets(5, 5, 5, 5);

         gbs.weightx=1;gbs.weighty=1;

         gbs.gridx=0;gbs.gridy=6;

         gbl.setConstraints(textField, gbs);

 //        // =====================================================

         gbs.anchor = GridBagConstraints.NORTH;

         return panel;

     }

 }

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