Java GridBagLayout

Java GridBagLayout类用于将组件垂直, 水平或沿其基线对齐。

组件的大小可能不同。每个GridBagLayout对象维护一个动态的矩形单元格网格。每个组件占据一个或多个单元格, 即其显示区域。每个组件都关联一个GridBagConstraints实例。借助约束对象, 我们在网格上排列了组件的显示区域。 GridBagLayout管理每个组件的最小和首选大小, 以确定组件的大小。

领域

有用的方法

例

import java.awt.Button;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;

import javax.swing.*;
public class GridBagLayoutExample extends JFrame{
	public static void main(String[] args) {
	        GridBagLayoutExample a = new GridBagLayoutExample();
	    }
		public GridBagLayoutExample() {
	GridBagLayoutgrid = new GridBagLayout();
	        GridBagConstraints gbc = new GridBagConstraints();
	        setLayout(grid);
	        setTitle("GridBag Layout Example");
	        GridBagLayout layout = new GridBagLayout();
	this.setLayout(layout);
	gbc.fill = GridBagConstraints.HORIZONTAL;
	gbc.gridx = 0;
	gbc.gridy = 0;
	this.add(new Button("Button One"), gbc);
	gbc.gridx = 1;
	gbc.gridy = 0;
	this.add(new Button("Button two"), gbc);
	gbc.fill = GridBagConstraints.HORIZONTAL;
	gbc.ipady = 20;
	gbc.gridx = 0;
	gbc.gridy = 1;
	this.add(new Button("Button Three"), gbc);
	gbc.gridx = 1;
	gbc.gridy = 1;
	this.add(new Button("Button Four"), gbc);
	gbc.gridx = 0;
	gbc.gridy = 2;
	gbc.fill = GridBagConstraints.HORIZONTAL;
	gbc.gridwidth = 2;
	this.add(new Button("Button Five"), gbc);
	        setSize(300, 300);
	        setPreferredSize(getSize());
	        setVisible(true);
	        setDefaultCloseOperation(EXIT_ON_CLOSE);
	
	    }
	
}

输出：

例子2

public class GridBagLayoutDemo {
final static boolean shouldFill = true;
final static boolean shouldWeightX = true;
final static boolean RIGHT_TO_LEFT = false;

public static void addComponentsToPane(Container pane) {
if (RIGHT_TO_LEFT) {
pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
}

JButton button;
pane.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
if (shouldFill) {
//natural height, maximum width
c.fill = GridBagConstraints.HORIZONTAL;
}

button = new JButton("Button 1");
if (shouldWeightX) {
c.weightx = 0.5;
}
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 0;
c.gridy = 0;
pane.add(button, c);

button = new JButton("Button 2");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 1;
c.gridy = 0;
pane.add(button, c);

button = new JButton("Button 3");
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.gridx = 2;
c.gridy = 0;
pane.add(button, c);

button = new JButton("Long-Named Button 4");
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 40;      //make this component tall
c.weightx = 0.0;
c.gridwidth = 3;
c.gridx = 0;
c.gridy = 1;
pane.add(button, c);

button = new JButton("5");
c.fill = GridBagConstraints.HORIZONTAL;
c.ipady = 0;       //reset to default
c.weighty = 1.0;   //request any extra vertical space
c.anchor = GridBagConstraints.PAGE_END; //bottom of space
c.insets = new Insets(10, 0, 0, 0);  //top padding
c.gridx = 1;       //aligned with button 2
c.gridwidth = 2;   //2 columns wide
c.gridy = 2;       //third row
pane.add(button, c);
}


private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("GridBagLayoutDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//Set up the content pane.
addComponentsToPane(frame.getContentPane());

//Display the window.
frame.pack();
frame.setVisible(true);
}

public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}

输出：