gridbaglayoutdemo.java

学习参考,java基本语法练习,包括一些常用的技巧

//这是GridBagLayout的一个实例
import java.awt.*;
import javax.swing.*;
public class GridBagLayoutDemo extends JFrame  
{
	JPanel p1;
	Canvas c;
    Choice cb;
	TextArea ta;
	JTextField tf;
	JButton b1, b2, b3;
	GridBagLayout gbl;
	GridBagConstraints gbc;
 	public GridBagLayoutDemo()
 	{
		p1=new JPanel();
		gbl=new GridBagLayout();
		p1.setLayout(gbl);
		gbc= new GridBagConstraints();
 		ta = new TextArea("这是文本域", 5, 10);
		cb = new Choice();		
		cb.addItem("刘津");
		cb.addItem("刘志成");	
		cb.addItem("王咏梅");
		tf = new JTextField("这是文本框");
		b1 = new JButton("按钮 1");
		b2 = new JButton("按钮 2");
		b3 = new JButton("按钮 3");
		c = new Canvas();  	
		c.setBackground(Color.blue);
		c.setSize(10, 5);
 		// 布局textarea
		gbc.weightx = 0;
		gbc.weighty = 0;
		gbc.fill = GridBagConstraints.BOTH;
		addComponent(ta, gbl, gbc, 0, 0, 1, 3); 
		// 布局按钮b1
		gbc.fill = GridBagConstraints.HORIZONTAL;
		addComponent(b1, gbl, gbc, 0, 1, 2, 1);
		// 布局choice
		addComponent(cb, gbl, gbc, 2, 1, 2, 1);
		// 布局按钮b2
		gbc.weightx = 1000;
		gbc.weighty = 1;
		gbc.fill = GridBagConstraints.BOTH;
		addComponent(b2, gbl, gbc, 1, 1, 1, 1);
		// 布局按钮b3
		gbc.weightx = 0;
		gbc.weighty = 0;
		gbc.fill = GridBagConstraints.BOTH;
		addComponent(b3, gbl, gbc, 1, 2, 1, 1);
		// 布局文本框tf
		addComponent(tf, gbl, gbc, 3, 0, 2, 1);
		// 布局画布c
		addComponent(c, gbl, gbc, 3, 2, 1, 1);
		setContentPane(p1);
		setTitle("网格袋布局演示");
 		setSize(250, 150);		
		setVisible(true);
	}
	//添加组件方法
 	private void addComponent(Component c, GridBagLayout g,
		GridBagConstraints gc, int row, int column, int width, int height)
	{
		gc.gridx = column;
 		gc.gridy = row;
		gc.gridwidth = width;
		gc.gridheight = height;
		g.setConstraints(c, gc);
		p1.add(c);	
	}
	public static void main(String args[])
	{
		GridBagLayoutDemo demo = new GridBagLayoutDemo();
	}
}