Java基础入门Swing中间容器的使用

import java.awt.*;
import javax.swing.*; 
public class Main extends JFrame{
	public Main(){
		this.setTitle("PanelDemo");
		JScrollPane scrollPane=new JScrollPane();
		//设置水平进度条需要时出现
		scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
		//设置垂直进度条一直出现
		scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
		
		JPanel panel=new JPanel();
		panel.add(new JButton("按钮1"));
		panel.add(new JButton("按钮2"));
		panel.add(new JButton("按钮3"));
		panel.add(new JButton("按钮4"));
		for(int i=5;i<100;i++){
			panel.add(new JButton("按钮"+i));
		}
		
		//将JPanel面板添加在滚动面板上显示
		scrollPane.setViewportView(panel);
		//将滚动面板添加到窗体的中部（CENTER）
		this.add(scrollPane,BorderLayout.CENTER);
		
		//创建窗体可关闭按钮
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setSize(400,250);
		this.setVisible(true);
	}
	public static void main(String[] args)throws Exception{
       new Main();
	}
}

package com.jesse.Kotlin.com.jesse.gui 
import java.awt.BorderLayout
import java.awt.Dimension
import javax.swing.*
 
class WindowMain { 
    private val rootContainer = JFrame("GUI Demo") 
    fun buildGui(){
        rootContainer.defaultCloseOperation = JFrame.EXIT_ON_CLOSE
        var label = JLabel("Hello world")
        rootContainer.contentPane.add(label, BorderLayout.CENTER)
        rootContainer.preferredSize = Dimension(400, 300)
 
        var menuPanel:JMenuBar = JMenuBar()
        menuPanel.add(JMenu("help"))
        rootContainer.jMenuBar = menuPanel
 
        rootContainer.pack()
        rootContainer.isVisible = true
    }
} 
fun main(args: Array<String>) {
    SwingUtilities.invokeLater {
        WindowMain().buildGui()
    }
}