Java 实训4 编写一个窗体程序显示日历

实训要求：

1.使用BorderLayout 进行总体布局

2.在North 位置放置包含两个按钮( 上月和下月)的Panel

3.在South 位置放置一个Label 用于显示当前年份和月份

4.在Center 位置放置一个显示日历的Panel

5.显示日历的Panel 设置7 行7 列的GridLayout 布局，其中第1行放置7

个按钮显示周“几”，其他6 行放置42 个Label 用于显示期。

6.启动程序时日历中默认显示当前月份的日历。

7.点击“上月”和“下月”可翻看上个月和下个月的日历。

8.程序运行结果如下图:

代码：

CalendaBean.java

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++) {
			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;
	}
}

Test.java

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class Test extends JFrame {
	JButton b1, b2, b3, b4, b5, b6, b7, bx, by;
	CalendaBean cb = new CalendaBean();
	JLabel[] label;
	JLabel now;

	public static void main(String[] args) {
		Test frame = new Test();
		frame.setSize(500, 400);
		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();
		bx = new JButton("上月");
		by = new JButton("下月");
		bx.setActionCommand("lastmonth");
		by.setActionCommand("nextmonth");
		bx.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				cb.actionPerformed(e);
			}
		});
		by.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				cb.actionPerformed(e);
			}
		});
		pNorth.add(bx);
		pNorth.add(by);
		add(pNorth, BorderLayout.NORTH);
		GridLayout grid = new GridLayout(7, 7);
		JPanel pCenter = new JPanel();
		b1 = new JButton("日");
		b2 = new JButton("一");
		b3 = new JButton("二");
		b4 = new JButton("三");
		b5 = new JButton("四");
		b6 = new JButton("五");
		b7 = new JButton("六");
		pCenter.add(b1);
		pCenter.add(b2);
		pCenter.add(b3);
		pCenter.add(b4);
		pCenter.add(b5);
		pCenter.add(b6);
		pCenter.add(b7);
		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++) {
			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);
	}

}

运行结果：