[JAVA] AWT를 이용한 간단한 캘린더 만들기

import java.awt.*;
import java.util.*;
import java.awt.event.*;
public class AwtCalendar extends Frame implements ItemListener {
 private Choice chyear = new Choice();//년도 선택
 private Choice chmonth = new Choice();//월 선택
 
 private Label yLabel = new Label("년");
 private Label mLabel = new Label("월");
 private GregorianCalendar gc;
 private int year, month;
 // 위치 지정용
 private Dimension dimen, dimen1;
 private int xpos, ypos;
 
 private Label[] dayLabel= new Label[7];
 private String day[]={"일","월","화","수","목","금","토"};
 //날자배치용 버튼
 private Button[] days = new Button[42];
 
 private Panel selectPanel = new Panel();
 
 private GridLayout grid = new GridLayout(7,7,5,5);
 
 private Calendar ca = Calendar.getInstance();
 
 AwtCalendar(){//생성자
  this.setTitle("Java Calendar Ver 1.0");
  this.setSize(550,500);
  dimen = Toolkit.getDefaultToolkit().getScreenSize();
  dimen1 = this.getSize();
  xpos =(int)(dimen.getWidth()/2-dimen1.getWidth()/2);
  ypos =(int)(dimen.getHeight()/2-dimen1.getHeight()/2);
  this.setLocation(xpos,ypos);
  this.setResizable(false);
  this.setVisible(true);
  
  init();
  
  this.addWindowListener(new WindowAdapter(){
   public void windowClosing(WindowEvent we){
    dispose();
    System.exit(0);
   }
  });
 }
 public void init(){
  select();
  calendar();
 }
 //기본 폼 만들기
 public void select(){
  Panel panel = new Panel(grid);
  //year
  for(int i=2020;i>=2000;i--){
   chyear.add(String.valueOf(i));
  }
  //month
  for(int i=1;i<=12;i++){
   chmonth.add(String.valueOf(i));
  }
  //week
  for(int i=0;i<day.length;i++){
   dayLabel[i]=new Label(day[i],Label.CENTER);
   panel.add(dayLabel[i]);
   dayLabel[i].setBackground(Color.GRAY);
  }
  dayLabel[6].setForeground(Color.BLUE);//토요일 색상
  dayLabel[0].setForeground(Color.RED);//일요일 색상
  
  for(int i=0;i<42;i++){
   days[i]=new Button("");
   if(i%7==0)
    days[i].setForeground(Color.RED);
   else if(i%7==6)
    days[i].setForeground(Color.BLUE);
   else
    days[i].setForeground(Color.BLACK);
   panel.add(days[i]);
  }
  selectPanel.add(chyear);selectPanel.add(yLabel);
  selectPanel.add(chmonth);selectPanel.add(mLabel);
  
  this.add(selectPanel,"North");
  this.add(panel,"Center");
  
  String m = (ca.get(Calendar.MONTH)+1)+"";
  String y = ca.get(Calendar.YEAR)+"";
  
  chyear.select(y);
  chmonth.select(m);
  chyear.addItemListener(this);
  chmonth.addItemListener(this);
 }
 //달력 만들기
 public void calendar(){
  year = Integer.parseInt(chyear.getSelectedItem());
  month = Integer.parseInt(chmonth.getSelectedItem());
  
  gc = new GregorianCalendar(year,month-1,1);
  int max = gc.getActualMaximum(gc.DAY_OF_MONTH);
  int week = gc.get(gc.DAY_OF_WEEK);
  
  String today = Integer.toString(ca.get(Calendar.DATE));
  
  for(int i=week;i<max+week;i++){
   days[i-1].setLabel((String.valueOf(i-week+1)));
   days[i-1].setBackground(Color.WHITE);
   if(today.equals(days[i-1].getLabel())){
    days[i-1].setBackground(Color.pink);
   }
  }
 }
 
 public void itemStateChanged(ItemEvent it){
  if(it.getStateChange()==ItemEvent.SELECTED){
   for(int i=0;i<42;i++){
    days[i].setLabel("");
    days[i].setBackground(Color.WHITE);
   }
   calendar();
  }
 }
 
 public static void main(String[] args) {
  new AwtCalendar();
 }

}