Java GridBagLayout简单电子邮件发送界面的实现

1. GridBagLayout网格块布局
   运行示例：

   代码：

import java.awt.Component;
import java.awt.Frame;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Label;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.Window;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class EmailTest extends Frame{
	public EmailTest(){
		Label receiver=new Label("收件人：");
		Label send=new Label("抄送：");
		Label theme=new Label("主题：");
		TextField re=new TextField();
		TextField se=new TextField();
		TextField th=new TextField();
		TextArea con=new TextArea();
		setLayout(new GridBagLayout());
		GridBagConstraints gb=new GridBagConstraints();
		gb.fill=GridBagConstraints.HORIZONTAL;//水平填充
		gb.weightx=0;//行长不变
		gb.weighty=0;//列高不变
		addToBag(receiver, gb, 0, 0, 1, 1);
		addToBag(send, gb, 0, 1, 1, 1);
		addToBag(theme, gb, 0,2, 1, 1);
		gb.weightx=100;//行自适应缩放
		gb.weighty=0;//列高不变
		addToBag(re, gb,1,0, 1, 1);
		addToBag(se, gb,1,1, 2, 1);
		addToBag(th, gb,1,2, 2, 1);
		gb.fill=GridBagConstraints.BOTH;//剩余全部填充
		gb.weightx=100;//行自适应缩放
		gb.weighty=100;//列高自适应缩放
		addToBag(con, gb,0,4,3,1);
		addWindowListener(new closeWin());//窗口关闭的监听事件
		/*addWindowListener(new WindowAdapter(){      
       	    	
       	    	public void windowClosing(WindowEvent e){
       	    		dispose();
       	    	}
       	    });
		*/
		setSize(300,300);
		setVisible(true);
	}
	void addToBag(Component c,GridBagConstraints g,int x,int y,int w,int h) {
		g.gridx=x;
		g.gridy=y;//x、y为在网格中（x,y）坐标
		g.gridwidth=w;//横向占几个网格
		g.gridheight=h;//竖向占几个网格
		add(c,g);
	}
	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		new EmailTest();
	}
}
/*
 * 如果不写closeWin类，右上角×关闭窗口按钮可能会失效
 */
class closeWin extends WindowAdapter{
	public void windowClosing(WindowEvent e) {
		Window w=e.getWindow();
		w.dispose();
	}
	
}

注意窗口关闭类不重写会失效。

本文地址：https://blog.csdn.net/qq_44467720/article/details/112007314