GridBagLayout练习

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

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：

  1 package com.wst.bj;
  2 
  3 import java.awt.GridBagConstraints;
  4 import java.awt.GridBagLayout;
  5 import java.awt.Insets;
  6 
  7 import javax.swing.JButton;
  8 import javax.swing.JFrame;
  9 import javax.swing.JPanel;
 10 import javax.swing.JTextField;
 11 
 12 public class GridBagTest2 {
 13 
 14     private JFrame jframe = new JFrame(); 
 15     private JButton bt1 = new JButton("1");
 16     private JButton bt2 = new JButton("2");
 17     private JButton bt3 = new JButton("3");
 18     private JButton bt4 = new JButton("4");
 19     private JButton bt5 = new JButton("5");
 20     private JButton bt6 = new JButton("6");
 21     private JButton bt7 = new JButton("7");
 22     private JButton bt8 = new JButton("8");
 23     private JButton bt9 = new JButton("9");
 24     private JButton bt0 = new JButton("0");
 25     private JButton btdot = new JButton(".");
 26     private JButton btsignleft = new JButton("(");
 27     private JButton btsignright = new JButton(")");
 28     private JButton btp = new JButton("+");
 29     private JButton btm = new JButton("-");
 30     private JButton btmp = new JButton("*");
 31     private JButton btd = new JButton("/");
 32     private JButton bte = new JButton("=");
 33     private JButton bt = new JButton("00");
 34     private JButton btclear = new JButton("cl");
 35     private JTextField textField = new JTextField();
 36 
 37     public GridBagTest2() {
 38         init();
 39     }
 40 
 41     private void init()
 42     {
 43         FrameUtil.initFram(jframe, 300, 400);
 44         JPanel jpanel = createPanel();
 45         jframe.add(jpanel);
 46     }
 47     
 48     
 49     private JPanel createPanel(){
 50         JPanel panel = new JPanel();
 51         
 52         GridBagLayout gbl = new GridBagLayout();
 53         GridBagConstraints gbs = new GridBagConstraints();
 54         panel.setLayout(gbl);
 55         
 56         panel.add(bt7);panel.add(bt8);panel.add(bt9);panel.add(btp);
 57         panel.add(bt4);panel.add(bt5);panel.add(bt6);
 58 //      panel.add(bt1);panel.add(bt2);panel.add(bt9);panel.add(btp);
 59         panel.add(bt1);panel.add(bt2);panel.add(bt3);panel.add(btm);
 60         panel.add(bt0);panel.add(btdot);
 61         panel.add(btsignleft);panel.add(btsignright);panel.add(bte);panel.add(btmp);
 62         panel.add(btclear);panel.add(bt);                panel.add(btd);
 63         panel.add(textField);
 64         
 65         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
 66         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
 67         gbs.gridx=0;gbs.gridy=0;
 68         gbl.setConstraints(bt7, gbs);
 69         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
 70         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
 71         gbs.gridx=1;gbs.gridy=0;
 72         gbl.setConstraints(bt8, gbs);
 73         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
 74         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
 75         gbs.gridx=2;gbs.gridy=0;
 76         gbl.setConstraints(bt9, gbs);
 77         
 78         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=2;
 79         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
 80         gbs.gridx=3;gbs.gridy=0;
 81         gbl.setConstraints(btp, gbs);    
 82         
 83         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
 84         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
 85         gbs.gridx=0;gbs.gridy=1;
 86         gbl.setConstraints(bt4, gbs);
 87         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
 88         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
 89         gbs.gridx=1;gbs.gridy=1;
 90         gbl.setConstraints(bt5, gbs);
 91         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
 92         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
 93         gbs.gridx=2;gbs.gridy=1;
 94         gbl.setConstraints(bt6, gbs);
 95         
 96         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
 97         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
 98         gbs.gridx=0;gbs.gridy=2;
 99         gbl.setConstraints(bt1, gbs);
100         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
101         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
102         gbs.gridx=1;gbs.gridy=2;
103         gbl.setConstraints(bt2, gbs);
104         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
105         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
106         gbs.gridx=2;gbs.gridy=2;
107         gbl.setConstraints(bt3, gbs);
108         
109         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=2;
110         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
111         gbs.gridx=3;gbs.gridy=2;
112         gbl.setConstraints(btm, gbs);
113         
114         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=2;gbs.gridheight=1;
115         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
116         gbs.gridx=0;gbs.gridy=3;
117         gbl.setConstraints(bt0, gbs);
118         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
119         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
120         gbs.gridx=2;gbs.gridy=3;
121         gbl.setConstraints(btdot, gbs);
122         
123         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
124         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
125         gbs.gridx=0;gbs.gridy=4;
126         gbl.setConstraints(btsignleft, gbs);
127         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
128         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
129         gbs.gridx=1;gbs.gridy=4;
130         gbl.setConstraints(btsignright, gbs);
131         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=2;
132         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
133         gbs.gridx=2;gbs.gridy=4;
134         gbl.setConstraints(bte, gbs);
135         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
136         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
137         gbs.gridx=3;gbs.gridy=4;
138         gbl.setConstraints(btmp, gbs);
139         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
140         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
141         gbs.gridx=0;gbs.gridy=5;
142         gbl.setConstraints(btclear, gbs);
143         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
144         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
145         gbs.gridx=1;gbs.gridy=5;
146         gbl.setConstraints(bt, gbs);
147         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=1;gbs.gridheight=1;
148         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
149         gbs.gridx=3;gbs.gridy=5;
150         gbl.setConstraints(btd, gbs);
151         
152         gbs.fill=GridBagConstraints.BOTH;gbs.gridwidth=4;gbs.gridheight=3;
153         gbs.insets=new Insets(5, 5, 5, 5);gbs.weightx=1;gbs.weighty=1;
154         gbs.gridx=0;gbs.gridy=6;
155         gbl.setConstraints(textField, gbs);
156         
157         return panel;
158     }
159 }

测试2：

  1 package com.wst.bj;
  2 
  3 
  4 import java.awt.GridBagConstraints;
  5 import java.awt.GridBagLayout;
  6 import java.awt.Insets;
  7 
  8 import javax.swing.JButton;
  9 import javax.swing.JFrame;
 10 import javax.swing.JPanel;
 11 import javax.swing.JTextField;
 12 
 13 public class GridBagTest4 {
 14 
 15     private JFrame jframe = new JFrame(); 
 16     private JButton bt1 = new JButton("1");
 17     private JButton bt2 = new JButton("2");
 18     private JButton bt3 = new JButton("3");
 19     private JButton bt4 = new JButton("4");
 20     private JButton bt5 = new JButton("5");
 21     private JButton bt6 = new JButton("6");
 22     private JButton bt7 = new JButton("7");
 23     private JButton bt8 = new JButton("8");
 24     private JButton bt9 = new JButton("9");
 25     private JButton bt0 = new JButton("0");
 26     private JButton btdot = new JButton(".");
 27     private JButton btsignleft = new JButton("(");
 28     private JButton btsignright = new JButton(")");
 29     private JButton btp = new JButton("+");
 30     private JButton btm = new JButton("-");
 31     private JButton btmp = new JButton("*");
 32     private JButton btd = new JButton("/");
 33     private JButton bte = new JButton("=");
 34     private JButton bt = new JButton("00");
 35     private JButton btclear = new JButton("cl");
 36     private JTextField textField = new JTextField();
 37 
 38     public GridBagTest4() {
 39         init();
 40     }
 41 
 42     private void init()
 43     {
 44         FrameUtil.initFram(jframe, 300, 400);
 45         JPanel jpanel = createPanel();
 46         jframe.add(jpanel);
 47     }
 48     
 49     
 50     private JPanel createPanel(){
 51         JPanel panel = new JPanel();
 52         
 53         GridBagLayout gbl = new GridBagLayout();
 54         GridBagConstraints gbs = new GridBagConstraints();
 55         panel.setLayout(gbl);
 56         
 57         panel.add(bt7);panel.add(bt8);panel.add(bt9);panel.add(btp);
 58         panel.add(bt4);panel.add(bt5);panel.add(bt6);
 59         panel.add(bt1);panel.add(bt2);panel.add(bt3);panel.add(btm);
 60         panel.add(bt0);panel.add(btdot);
 61         panel.add(btsignleft);panel.add(btsignright);panel.add(bte);panel.add(btmp);
 62         panel.add(btclear);panel.add(bt);                panel.add(btd);
 63         panel.add(textField);
 64         
 65         gbs.fill=GridBagConstraints.NONE;
 66 //        gbs.gridwidth=1;gbs.gridheight=1;
 67 //        gbs.insets=new Insets(5, 5, 5, 5);
 68 //        gbs.ipadx = 100;
 69 //        gbs.ipady = 100;
 70         gbs.anchor = GridBagConstraints.WEST;
 71         gbs.weightx=1;gbs.weighty=1;
 72         gbs.gridx=0;gbs.gridy=0;
 73         gbl.setConstraints(bt7, gbs);
 74         
 75         gbs.fill=GridBagConstraints.NONE;
 76 //        gbs.gridwidth=1;gbs.gridheight=1;
 77 //        gbs.insets=new Insets(5, 5, 5, 5);
 78 //        gbs.weightx=1;gbs.weighty=1;
 79         gbs.anchor = GridBagConstraints.NORTHEAST;
 80         gbs.gridx=1;gbs.gridy=0;
 81         gbl.setConstraints(bt8, gbs);
 82         
 83         gbs.fill=GridBagConstraints.NONE;
 84 //        gbs.gridwidth=1;gbs.gridheight=1;
 85 //        gbs.insets=new Insets(5, 5, 5, 5);
 86 //        gbs.weightx=1;gbs.weighty=1;
 87         gbs.anchor = GridBagConstraints.SOUTH;
 88         gbs.gridx=2;gbs.gridy=0;
 89         gbl.setConstraints(bt9, gbs);
 90 //        
 91         gbs.fill=GridBagConstraints.BOTH;
 92         gbs.gridwidth=1;gbs.gridheight=2;
 93 ////        gbs.insets=new Insets(5, 5, 5, 5);
 94 ////        gbs.weightx=1;gbs.weighty=1;
 95         gbs.gridx=3;gbs.gridy=0;
 96         gbl.setConstraints(btp, gbs);    
 97         // =====================================================
 98         gbs.fill=GridBagConstraints.VERTICAL;
 99         gbs.gridwidth=1;gbs.gridheight=1;
100 //        gbs.insets=new Insets(5, 5, 5, 5);
101 //        gbs.weightx=1;gbs.weighty=1;
102         gbs.anchor = GridBagConstraints.WEST;
103         gbs.gridx=0;gbs.gridy=1;
104         gbl.setConstraints(bt4, gbs);
105 //        
106         gbs.fill=GridBagConstraints.VERTICAL;
107         gbs.gridwidth=1;gbs.gridheight=1;
108 //        gbs.insets=new Insets(5, 5, 5, 5);
109 //        gbs.weightx=1;gbs.weighty=1;
110         gbs.anchor = GridBagConstraints.SOUTHEAST;
111         gbs.gridx=1;gbs.gridy=1;
112         gbl.setConstraints(bt5, gbs);
113         
114         gbs.fill=GridBagConstraints.VERTICAL;
115         gbs.gridwidth=1;gbs.gridheight=1;
116 //        gbs.insets=new Insets(5, 5, 5, 5);
117 //        gbs.weightx=1;gbs.weighty=1;
118         gbs.anchor = GridBagConstraints.CENTER;
119         gbs.gridx=2;gbs.gridy=1;
120         gbl.setConstraints(bt6, gbs);
121         // =====================================================
122         gbs.fill=GridBagConstraints.HORIZONTAL;
123         gbs.gridwidth=1;gbs.gridheight=1;
124 //        gbs.insets=new Insets(5, 5, 5, 5);
125 //        gbs.weightx=1;gbs.weighty=1;
126         gbs.anchor = GridBagConstraints.NORTH;
127         gbs.gridx=0;gbs.gridy=2;
128         gbl.setConstraints(bt1, gbs);
129         
130         gbs.fill=GridBagConstraints.HORIZONTAL;
131         gbs.gridwidth=1;gbs.gridheight=1;
132 //        gbs.insets=new Insets(5, 5, 5, 5);
133 //        gbs.weightx=1;gbs.weighty=1;
134         gbs.anchor = GridBagConstraints.SOUTHEAST;
135         gbs.gridx=1;gbs.gridy=2;
136         gbl.setConstraints(bt2, gbs);
137         
138         gbs.fill=GridBagConstraints.HORIZONTAL;
139         gbs.gridwidth=1;gbs.gridheight=1;
140 //        gbs.insets=new Insets(5, 5, 5, 5);
141 //        gbs.weightx=1;gbs.weighty=1;
142         gbs.anchor = GridBagConstraints.CENTER;
143         gbs.gridx=2;gbs.gridy=2;
144         gbl.setConstraints(bt3, gbs);
145         
146         gbs.fill=GridBagConstraints.BOTH;        
147         gbs.gridwidth=1;gbs.gridheight=2;
148 //        gbs.insets=new Insets(5, 5, 5, 5);
149 //        gbs.weightx=1;gbs.weighty=1;
150         gbs.gridx=3;gbs.gridy=2;
151         gbl.setConstraints(btm, gbs);
152         // =====================================================
153         gbs.fill=GridBagConstraints.BOTH;
154         gbs.gridwidth=2;gbs.gridheight=1;
155 //        gbs.insets=new Insets(5, 5, 5, 5);
156 //        gbs.weightx=1;gbs.weighty=1;
157         gbs.gridx=0;gbs.gridy=3;
158         gbl.setConstraints(bt0, gbs);
159         
160         gbs.fill=GridBagConstraints.BOTH;
161         gbs.gridwidth=1;gbs.gridheight=1;
162 //        gbs.insets=new Insets(5, 5, 5, 5);
163 //        gbs.weightx=1;gbs.weighty=1;
164         gbs.gridx=2;gbs.gridy=3;
165         gbl.setConstraints(btdot, gbs);
166         // =====================================================
167         gbs.fill=GridBagConstraints.BOTH;
168         gbs.gridwidth=1;gbs.gridheight=1;
169 //        gbs.insets=new Insets(5, 5, 5, 5);
170 //        gbs.weightx=1;gbs.weighty=1;
171         gbs.gridx=0;gbs.gridy=4;
172         gbl.setConstraints(btsignleft, gbs);
173         
174         gbs.fill=GridBagConstraints.BOTH;
175         gbs.gridwidth=1;gbs.gridheight=1;
176         gbs.insets=new Insets(7, 7, 2, 2);
177 //        gbs.weightx=1;gbs.weighty=1;
178         gbs.gridx=1;gbs.gridy=4;
179         gbl.setConstraints(btsignright, gbs);
180         
181         gbs.fill=GridBagConstraints.BOTH;
182         gbs.gridwidth=1;gbs.gridheight=2;
183         gbs.insets=new Insets(0, 0, 0, 0);
184 //        gbs.weightx=1;gbs.weighty=1;
185         gbs.gridx=2;gbs.gridy=4;
186         gbl.setConstraints(bte, gbs);
187         
188         gbs.fill=GridBagConstraints.BOTH;
189         gbs.gridwidth=1;gbs.gridheight=1;
190 //        gbs.insets=new Insets(5, 5, 5, 5);
191 //        gbs.weightx=1;gbs.weighty=1;
192         gbs.gridx=3;gbs.gridy=4;
193         gbl.setConstraints(btmp, gbs);
194         // =====================================================
195         gbs.fill=GridBagConstraints.BOTH;
196         gbs.gridwidth=1;gbs.gridheight=1;
197 //        gbs.insets=new Insets(5, 5, 5, 5);
198         gbs.weightx=0;gbs.weighty=0;
199         gbs.gridx=0;gbs.gridy=5;
200         gbl.setConstraints(btclear, gbs);
201         
202         gbs.fill=GridBagConstraints.BOTH;
203         gbs.gridwidth=1;gbs.gridheight=1;
204 //        gbs.insets=new Insets(5, 5, 5, 5);
205 //        gbs.weightx=1;gbs.weighty=1;
206         gbs.gridx=1;gbs.gridy=5;
207         gbl.setConstraints(bt, gbs);
208         
209         gbs.fill=GridBagConstraints.NONE;
210         gbs.gridwidth=1;gbs.gridheight=1;
211 //        gbs.insets=new Insets(5, 5, 5, 5);
212 //        gbs.weightx=1;gbs.weighty=1;
213         gbs.anchor = GridBagConstraints.EAST;
214         gbs.gridx=3;gbs.gridy=5;
215         gbl.setConstraints(btd, gbs);
216         // =====================================================
217         gbs.fill=GridBagConstraints.BOTH;
218         gbs.gridwidth=4;gbs.gridheight=3;
219 //        gbs.insets=new Insets(5, 5, 5, 5);
220         gbs.weightx=1;gbs.weighty=1;
221         gbs.gridx=0;gbs.gridy=6;
222         gbl.setConstraints(textField, gbs);
223 //        // =====================================================
224         gbs.anchor = GridBagConstraints.NORTH;
225         return panel;
226     }
227 }