您的位置：首页 > 其它

[转载]布局管理器GridBagLayout的使用

2010-01-19 16:18 330 查看
[J] 布局管理器 GridBagLayout 的使用

Java布局管理器有FlowLayout, BorderLayout, GridLayout, CardLayout, GridBagLayout等，相比较而言，GridBagLayout的使用方式要复杂一些。但它的表现力也最丰富。之前我对GridBagLayout的使用也是一知半解，具体的用法不是十分的明了。这两天认真的看了这一块，就写了下来。
使用 GridBagLayout的主要工作就是设置组件的约束，通过GridBagConstraints的实例设置。
GridBagConstraints 主要有11个参数：gridx, gridy, gridwidth ,gridheight ,anchor ,fill ,weightx ,weighty ,insets ,ipadx ,ipady；
每个参数的意义可以参考java api上的说明。本文的最后附有anchor属性和fill属性的示例。实际使用中根据自己的需要设置特定的属性。
在Java api中给出了一个GridBagLayout的例子和实现，下面的是自己的实现方式。



[CODE]
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class GridBagLayoutDemo extends Applet {
GridBagLayout gbaglayout;
GridBagConstraints constraints;
public void init() {
gbaglayout = new GridBagLayout();
constraints = new GridBagConstraints();
setLayout(gbaglayout);

//Button 1
Button btn1 = new Button("Button01");
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridwidth = 1;
constraints.gridheight = 1;
constraints.anchor = GridBagConstraints.CENTER;
constraints.fill = GridBagConstraints.NONE;
constraints.weightx = 0.0;
constraints.weighty = 0.0;
constraints.insets = new Insets(0, 0, 0, 0);
constraints.ipadx = 0;
constraints.ipady = 0;
makeButton(gbaglayout, constraints, btn1);

//Button 2
Button btn2 = new Button("Button02");
constraints.gridx = 1;
makeButton(gbaglayout, constraints, btn2);

//Button 3
Button btn3 = new Button("Button03");
constraints.gridx = 2;
makeButton(gbaglayout, constraints, btn3);

//Button 4
Button btn4 = new Button("Button04");
constraints.gridx = 3;
makeButton(gbaglayout, constraints, btn4);

//Button 5
Button btn5 = new Button("Button05");
constraints.gridx = 0;
constraints.gridy = 1;
constraints.gridwidth = 4;
makeButton(gbaglayout, constraints, btn5);

//Button 6
Button btn6 = new Button("Button06");
constraints.gridx = 0;
constraints.gridy = 2;
constraints.gridwidth = 3;
makeButton(gbaglayout, constraints, btn6);

//Button 7
Button btn7 = new Button("Button07");
constraints.gridx = 3;
constraints.gridy = 2;
constraints.gridwidth = 1;
makeButton(gbaglayout, constraints, btn7);

//Button 8
Button btn8 = new Button("Button08");
constraints.gridx = 0;
constraints.gridy = 3;
constraints.gridwidth = 1;
constraints.gridheight = 2;
makeButton(gbaglayout, constraints, btn8);

//Button 9
Button btn9 = new Button("Button09");
constraints.gridx = 1;
constraints.gridy = 3;
constraints.gridwidth = 3;
constraints.gridheight = 1;
makeButton(gbaglayout, constraints, btn9);

//Button 10
Button btn10 = new Button("Button10");
constraints.gridx = 1;
constraints.gridy = 4;
constraints.gridwidth = 3;
constraints.gridheight = 1;
makeButton(gbaglayout, constraints, btn10);
}
private void makeButton(GridBagLayout gbaglayout, GridBagConstraints constraints, Component component) {
gbaglayout.setConstraints(component, constraints);
add(component);
}
public static void main(String[] args) {
Frame frame = new Frame("GridBagLayoutDemo");
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});

GridBagLayoutDemo demo = new GridBagLayoutDemo();
demo.init();

frame.add(BorderLayout.CENTER, demo);
frame.setSize(270, 150);
//frame.setSize(361, 254);
frame.setVisible(true);
}
}
[CODE]
显示窗口可以如图所示划分为 5 行和 4 列，每个按钮所在的单元可以很容易的确定，所以 gridx 和 gridy 的值都很容易确定，组件放置在的位置也就确定了。
然而，组件都有一个默认的大小，它和它所在的单元格大小一般情况下都是不同的，并且如果窗口发生变化时，组件做出什么样的改变就要用到fill ,weightx 和 weighty了。
结合具体的例子来看：
设置 Button 1
//Button 1
Button btn1 = new Button("Button01");
//所在单元格为(0, 0)
constraints.gridx = 0;
constraints.gridy = 0;
//占用一个长度长和一个长度宽
constraints.gridwidth = 1;
constraints.gridheight = 1;
//这里使用默认的 anchor
constraints.anchor = GridBagConstraints.CENTER;
//设置NONE填充
constraints.fill = GridBagConstraints.NONE;
//设置填充权重
constraints.weightx = 0.0;
constraints.weighty = 0.0;
//Insets, ipadx, ipady使用默认值
constraints.insets = new Insets(0, 0, 0, 0);
constraints.ipadx = 0;
constraints.ipady = 0;
//添加 Button01 按钮
makeButton(gbaglayout, constraints, btn1);

设置 Button02, Button03, Button04
//Button 2
Button btn2 = new Button("Button02");
constraints.gridx = 1;
makeButton(gbaglayout, constraints, btn2);
//Button 3
Button btn3 = new Button("Button03");
constraints.gridx = 2;
makeButton(gbaglayout, constraints, btn3);
//Button 4
Button btn4 = new Button("Button04");
constraints.gridx = 3;
makeButton(gbaglayout, constraints, btn4);
Button02, Button03, Button04和Button01的区别是，只需要设置他们的gridx值;其他的不变。

设置 Button05
//Button 5
Button btn5 = new Button("Button05");
//所在单元格为(0, 1)
constraints.gridx = 0;
constraints.gridy = 1;
//占用了所有的4个单元格宽度 ，一个单元格高，省略没写
constraints.gridwidth = 4;
makeButton(gbaglayout, constraints, btn5);

设置 Button06
//Button 6
Button btn6 = new Button("Button06");
//所在单元格为(0, 2)
constraints.gridx = 0;
constraints.gridy = 2;
//占用了所有的3个单元格宽度 ，一个单元格高，省略没写
constraints.gridwidth = 3;
makeButton(gbaglayout, constraints, btn6);

设置 Button07
//Button 7
Button btn7 = new Button("Button07");
//所在单元格为(3, 2)
constraints.gridx = 3;
constraints.gridy = 2;
//占用了所有的1个单元格宽度 ，一个单元格高，省略没写
constraints.gridwidth = 1;
makeButton(gbaglayout, constraints, btn7);

设置 Button08
//Button 8
Button btn8 = new Button("Button08");
//所在单元格为(0, 3)
constraints.gridx = 0;
constraints.gridy = 3;
//占用了所有的1个单元格宽度 ，2个单元格高
constraints.gridwidth = 1;
constraints.gridheight = 2;
makeButton(gbaglayout, constraints, btn8);

设置 Button09
//Button 9
Button btn9 = new Button("Button09");
//所在单元格为(1, 3)
constraints.gridx = 1;
constraints.gridy = 3;
//占用了所有的3个单元格宽度 ，1个单元格高
constraints.gridwidth = 3;
constraints.gridheight = 1;
makeButton(gbaglayout, constraints, btn9);

设置 Button10
//Button 10
Button btn10 = new Button("Button10");
//所在单元格为(1, 4)
constraints.gridx = 1;
constraints.gridy = 4;
//占用了所有的3个单元格宽度 ，1个单元格高，由于和Button09一样，也可以不写
constraints.gridwidth = 3;
constraints.gridheight = 1;
makeButton(gbaglayout, constraints, btn10);
设置好10个按钮之后，看看结果如何：



和目标差别还很大,但它确实是按照期望的方式，在特定的单元格内显示了。



为什么有差别呢？原因是单元格比按钮默认的大小要大，没有设置fill方式。
由于需要Button01, Button02, Button03 和 Button04的长度充满单元格，可修改 fill 属性为：constraints.fill = GridBagConstraints.HORIZONTAL;
同时改变constraints.weightx = 1.0;使得窗口变化时按钮能随之伸长(如果不改变weightx值，改变窗口大小时，看看会有什么效果)。
显示结果：



可以看到 Button08有问题，更改相应部分：
//Button 8
Button btn8 = new Button("Button08");
constraints.gridx = 0;
constraints.gridy = 3;
constraints.gridwidth = 1;
constraints.gridheight = 2;
//设置Button08的 fill 为 BOTH
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 1.0;
constraints.weighty = 1.0;
makeButton(gbaglayout, constraints, btn8);
//Button09
Button btn9 = new Button("Button09");
constraints.gridx = 1;
constraints.gridy = 3;
constraints.gridwidth = 3;
constraints.gridheight = 1;
//不需要垂直变化
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.weightx = 1.0;
constraints.weighty = 0.0;
makeButton(gbaglayout, constraints, btn9);
//Button 10
Button btn10 = new Button("Button10");
constraints.gridx = 1;
constraints.gridy = 4;
constraints.gridwidth = 3;
constraints.gridheight = 1;
//需要垂直变化
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 1.0;
constraints.weighty = 1.0;
makeButton(gbaglayout, constraints, btn10);
好了，所有的属性设置好了。



完整代码：
[CODE]
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class GridBagLayoutDemo extends Applet {
GridBagLayout gbaglayout;
GridBagConstraints constraints;
public void init() {
gbaglayout = new GridBagLayout();
constraints = new GridBagConstraints();
setLayout(gbaglayout);

//Button 1
Button btn1 = new Button("Button01");
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridwidth = 1;
constraints.gridheight = 1;
constraints.anchor = GridBagConstraints.CENTER;
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.weightx = 1.0;
constraints.weighty = 0.0;
constraints.insets = new Insets(0, 0, 0, 0);
constraints.ipadx = 0;
constraints.ipady = 0;
makeButton(gbaglayout, constraints, btn1);

//Button 2
Button btn2 = new Button("Button02");
constraints.gridx = 1;
makeButton(gbaglayout, constraints, btn2);

//Button 3
Button btn3 = new Button("Button03");
constraints.gridx = 2;
makeButton(gbaglayout, constraints, btn3);

//Button 4
Button btn4 = new Button("Button04");
constraints.gridx = 3;
makeButton(gbaglayout, constraints, btn4);

//Button 5
Button btn5 = new Button("Button05");
constraints.gridx = 0;
constraints.gridy = 1;
constraints.gridwidth = 4;
makeButton(gbaglayout, constraints, btn5);

//Button 6
Button btn6 = new Button("Button06");
constraints.gridx = 0;
constraints.gridy = 2;
constraints.gridwidth = 3;
makeButton(gbaglayout, constraints, btn6);

//Button 7
Button btn7 = new Button("Button07");
constraints.gridx = 3;
constraints.gridy = 2;
constraints.gridwidth = 1;
makeButton(gbaglayout, constraints, btn7);

//Button 8
Button btn8 = new Button("Button08");
constraints.gridx = 0;
constraints.gridy = 3;
constraints.gridwidth = 1;
constraints.gridheight = 2;
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 1.0;
constraints.weighty = 1.0;
makeButton(gbaglayout, constraints, btn8);

//Button 9
Button btn9 = new Button("Button09");
constraints.gridx = 1;
constraints.gridy = 3;
constraints.gridwidth = 3;
constraints.gridheight = 1;
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.weightx = 1.0;
constraints.weighty = 0.0;
makeButton(gbaglayout, constraints, btn9);

//Button 10
Button btn10 = new Button("Button10");
constraints.gridx = 1;
constraints.gridy = 4;
constraints.gridwidth = 3;
constraints.gridheight = 1;
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 1.0;
constraints.weighty = 1.0;
makeButton(gbaglayout, constraints, btn10);
}
private void makeButton(GridBagLayout gbaglayout, GridBagConstraints constraints, Component component) {
gbaglayout.setConstraints(component, constraints);
add(component);
}
public static void main(String[] args) {
Frame frame = new Frame("GridBagLayoutDemo");
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});

GridBagLayoutDemo demo = new GridBagLayoutDemo();
demo.init();

frame.add(BorderLayout.CENTER, demo);
frame.setSize(270, 150);
//frame.setSize(361, 254);
frame.setVisible(true);
}
}
[CODE]
以下是 fill 和 anchor 的示例：
fill的4种方式：



anchor的9种方式：



内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 点击这里给我发消息
标签： 
相关文章推荐
新的分享
章节导航