gridbaglayouttest.java

《Java程序设计与应用》-张仕斌-源程序 《Java程序设计与应用》-张仕斌-源程序

//GridBagLayoutTest.java
import java.awt.*;
import javax.swing.*;

public class GridBagLayoutTest extends JFrame {
	GridBagLayout gb = null;      //布局管理对象
	GridBagConstraints gbc = null;  //布局辅助对象
	Container cp = null;          //当前容器
	JLabel lblTitle = null;       //标题标签
	JLabel lblUser = null;        
	JLabel lblPwd = null;
	JTextField txtUser = null;      //用户名文本框
	JPasswordField txtPwd = null;   //密码框
	JButton btnOK = null;           //确定按钮
	
	public GridBagLayoutTest() {
		super("GridBagLayout Test");
		gb = new GridBagLayout();      //创建布局管理器
		cp = this.getContentPane();    //取得当前容器
		cp.setLayout(gb);              //设置当前容器的布局管理器
		
		gbc = new GridBagConstraints();   //创建辅助对象
		//创建每个组件
		lblTitle = new JLabel("用户登录");
		lblUser = new JLabel("用户名:");
		lblPwd = new JLabel("密    码:");
		txtUser = new JTextField(10);
		txtPwd = new JPasswordField(10);
		btnOK = new JButton("确定");
		//设置当前填充模式为水平拉伸
		gbc.fill = GridBagConstraints.HORIZONTAL;
		//调用自定义函数addComponent()来把标题标签添加到容器中
		addComponent(lblTitle,0,1,1,1);
		
		gbc.fill = GridBagConstraints.NONE;
		gbc.anchor = GridBagConstraints.EAST;
		addComponent(lblUser,1,0,1,1);
		
		addComponent(lblPwd,2,0,1,1);
		
		gbc.fill = GridBagConstraints.HORIZONTAL;
		addComponent(txtUser,1,1,1,2);
		
		addComponent(txtPwd,2,1,1,2);
		
		addComponent(btnOK,3,1,1,1);
	}
	
	/* 自定义函数,用来把组件c添加到当前容器中,参数含义如下:
	 * c - 要加入的组件
	 * row - 该组件所处的网格开始行(从0开始编号)
	 * col - 该组件所处的网格开始列(从0开始编号)
	 * nrow - 该组件宽要占的网格单元格数目
	 * ncol - 该组件高要占的网格单元格数目 
	 */	  
	public void addComponent(Component c,int row, int col, int nrow, int ncol) {
		gbc.gridx = col;  //给辅助对象赋值
		gbc.gridy = row;
		gbc.gridwidth = ncol;
		gbc.gridheight = nrow;
		gb.setConstraints(c,gbc);  //设置组件的属性
		cp.add(c);   //添加组件c到容器cp中
	}
	
	public static void main(String[]ars) {
		GridBagLayoutTest gbt = new GridBagLayoutTest();
		gbt.setSize(300,180);
		gbt.setDefaultCloseOperation(EXIT_ON_CLOSE);
		gbt.setVisible(true);
	}
}