一、Java窗体设置

package ui;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Window;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Demo {
 
 public static void main(String[] args) {
  //定义一个窗体对象f，窗体命名为"美丽的窗口"
   JFrame f=new JFrame("美丽的窗口");
  //用户单击窗口的关闭按钮是程序执行操作
  f.setDefaultCloseOperation(3);
  //把MyPanel设置为f的内容面板
  f.setContentPane(new MyPanel());
  //离显示屏上边缘100像素，里显示屏左边缘200像素
        f.setLocation(100,200);
        //设置窗体的大小为300*200像素大小
        f.setSize(300,200);
        //设置窗体是否可以调整大小，参数为布尔值
        f.setResizable(false);
  //设置窗体可见
  f.setVisible(true);
 }
 
}

class MyPanel extends JPanel {

 public void paintComponent(Graphics g) {
  //设置成红色
  g.setColor(new Color(255,0,0));
  //画一个矩形
  g.fillRect(32,108,32,32);
  //写字符串
  g.drawString("萌萌哒   ^_^ " , 54, 64);
  //字体的颜色和大小
  //g.setFont(new Font("黑体",Font.BOLD,32));
  
 }
}

setDefaultCloseOperation(int operation)：设置用户在此窗体上发起 "close" 时默认执行的操作。

方法中的参数解释如下：

0或DO_NOTHING_ON_CLOSE (defined in WindowConstants): Don't do anything; require the program to handle the operation in the windowClosing method of a registered WindowListener object. 1或HIDE_ON_CLOSE (defined in WindowConstants): Automatically hide the frame after invoking any registered WindowListener objects. 2或DISPOSE_ON_CLOSE (defined in WindowConstants): Automatically hide and dispose the frame after invoking any registered WindowListener objects. 3或EXIT_ON_CLOSE (defined in JFrame): Exit the application using theSystemexit method. Use this only in applications