Java实训——编写一个窗体程序显示日历。

实训要求：

代码：

Test类：

import java.awt.*;  
import java.awt.event.*;  
import javax.swing.*;  
  
public class Test extends JFrame {  
    JButton week1, week2, week3, week4, week5, week6, week7, next, pro;  
    CalendaBean cb = new CalendaBean();  
    JLabel[] label;  
    JLabel now;  
  
    public static void main(String[] args) {  
        Test frame = new Test();  
        frame.setBounds(650,300,550,550); 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
        frame.setTitle("日历");  
        frame.setVisible(true);  
  
    }  
  
    public Test() {  
        int year, month;  
        setLayout(new BorderLayout());  
        JPanel pNorth = new JPanel();  
        cb = new CalendaBean();  
        cb.setYear(2017);  
        cb.setMonth(11);  
        String[] a = cb.getCalendar();  
        next = new JButton("上月");  
        pro = new JButton("下月");  
        next.setActionCommand("lastmonth");  
        pro.setActionCommand("nextmonth");  
        next.addActionListener(new ActionListener() {  
            public void actionPerformed(ActionEvent e) {  
                cb.actionPerformed(e);  
            }  
        });  
        pro.addActionListener(new ActionListener() {  
            public void actionPerformed(ActionEvent e) {  
                cb.actionPerformed(e);  
            }  
        });  
        pNorth.add(next);  
        pNorth.add(pro);  
        add(pNorth, BorderLayout.NORTH);  
        GridLayout grid = new GridLayout(8, 7);  
        JPanel pCenter = new JPanel();  
        week1 = new JButton("日");  
        week2 = new JButton("一");  
        week3 = new JButton("二");  
        week4 = new JButton("三");  
        week5 = new JButton("四");  
        week6 = new JButton("五");  
        week7 = new JButton("六");  
        pCenter.add(week1);  
        pCenter.add(week2);  
        pCenter.add(week3);  
        pCenter.add(week4);  
        pCenter.add(week5);  
        pCenter.add(week6);  
        pCenter.add(week7);  
        label = new JLabel[42];  
        for (int i = 0; i < 42; i++) {  
            label[i] = new JLabel();  
            pCenter.add(label[i]);  
        }  
        cb.label = this.label;  
        for (int i = 0; i < a.length; i++) {  
            if (i % 7 == 0) {  
                label[i].setText("");  
            }  
            label[i].setText("          "+a[i]);  
        }  
        pCenter.setLayout(grid);  
        add(pCenter, BorderLayout.CENTER);  
        JPanel pSouth = new JPanel();  
        now = new JLabel();  
        now.setText("日历:" + cb.year + "年" + cb.month + "月");  
        cb.now = now;  
        pSouth.add(now);  
        add(pSouth, BorderLayout.SOUTH);  
    }  
  
} 

CalendaBean类：

import java.awt.event.ActionEvent;  
import java.awt.event.ActionListener;  
import java.util.Calendar;  
  
import javax.swing.*;  
public class CalendaBean implements ActionListener {  
    JLabel[] label;  
    JLabel now;  
    String[] day;  
    int year = 0, month = 0;  
    public void setYear(int year) {  
        this.year = year;  
    }  
  
    public void setMonth(int month) {  
        this.month = month;  
    }  
  
    public void actionPerformed(ActionEvent e) {  
        String str = e.getActionCommand();  
        if (str.equals("lastmonth")) {  
            month--;  
            if (month == 0) {  
                month = 12;  
                year--;  
            }  
        }  
        else if (str.equals("nextmonth")) {  
            month++;  
            if (month == 13) {  
                month = 1;  
                year++;  
            }  
        }  
        now.setText("日历:" + year + "年" + month + "月");  
        String[] a = getCalendar();  
        for (int i = 0; i < a.length; i++) {  
            if (i % 7 == 0) {  
                label[i].setText("");  
            }  
            label[i].setText("          "+a[i]);  
        }  
          
    }  
  
    public String[] getCalendar() {  
        String[] a = new String[42];  
        Calendar rili = Calendar.getInstance();  
        rili.set(year, month - 1, 1);  
        int weekDay = rili.get(Calendar.DAY_OF_WEEK) - 1;  
        int day = 0;  
        if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8  
                || month == 10 || month == 12) {  
            day = 31;  
        }  
        if (month == 4 || month == 6 || month == 9 || month == 11) {  
            day = 30;  
        }  
        if (month == 2) {  
            if ((year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0))  
                day = 29;  
            else  
                day = 28;  
        }  
        for (int i = 0; i < weekDay; i++)  
            a[i] = "";  
        for (int i = weekDay, n = 1; i < weekDay + day; i++) {  
            a[i] = String.valueOf(n);  
            n++;  
        }  
        for (int i = weekDay + day; i < a.length; i++)  
            a[i] = "";  
        return a;  
    }  
} 

运行结果:

小结：

学习了Calendar类，其他的，界面的话顺着来就好。