如何使用JFrame完成动态模拟时钟

使用JFrame完成动态模拟时钟的攻略可以分为以下几个步骤：

1. 导入Swing包

使用JFrame需要导入Swing包，可以在文件头添加以下代码：

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.FontMetrics;
import java.awt.Dimension;
import java.awt.BasicStroke;
import java.util.Calendar;
import java.util.Date;

2. 创建时钟面板

使用JPanel创建一个时钟面板，可以设置时钟面板的背景色、大小等属性，代码如下所示：

public class ClockPanel extends JPanel {

    private int width, height;
    private Date date;

    public ClockPanel(int width, int height) {
        this.width = width;
        this.height = height;
        setPreferredSize(new Dimension(width, height));
        setBackground(Color.WHITE);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        drawClock(g);
    }

    private void drawClock(Graphics g) {
        // 画钟面
        g.setColor(Color.BLACK);
        g.drawOval(10, 10, width - 20, height - 20);
        g.fillOval(10, 10, width - 20, height - 20);
        // 画刻度
        for (int i = 0; i < 12; i++) {
            double angle = Math.PI / 6 * i;
            int x1 = (int)(width / 2 + (width / 2 - 40) * Math.cos(angle));
            int y1 = (int)(height / 2 + (height / 2 - 40) * Math.sin(angle));
            int x2 = (int)(width / 2 + (width / 2 - 20) * Math.cos(angle));
            int y2 = (int)(height / 2 + (height / 2 - 20) * Math.sin(angle));
            g.drawLine(x1, y1, x2, y2);
        }
        // 画数字
        FontMetrics fm = g.getFontMetrics();
        int fontHeight = fm.getHeight();
        for (int i = 1; i <= 12; i++) {
            double angle = Math.PI / 6 * i;
            String numberStr = String.valueOf(i);
            int x = (int)(width / 2 + (width / 2 - 60) * Math.cos(angle)) - fm.stringWidth(numberStr) / 2;
            int y = (int)(height / 2 + (height / 2 - 60) * Math.sin(angle)) + fontHeight / 3;
            g.drawString(numberStr, x, y);
        }
        // 画指针
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        int hour = calendar.get(Calendar.HOUR);
        int minute = calendar.get(Calendar.MINUTE);
        int second = calendar.get(Calendar.SECOND);
        int millis = calendar.get(Calendar.MILLISECOND);
        int hourAngle = (hour % 12) * 30 + minute / 2;
        int minuteAngle = minute * 6;
        int secondAngle = second * 6 + millis / 600;
        g.setColor(Color.RED);
        g.setStroke(new BasicStroke(3));
        drawPointer(g, hourAngle, 60, 5);
        drawPointer(g, minuteAngle, 80, 3);
        drawPointer(g, secondAngle, 100, 1);
    }

    private void drawPointer(Graphics g, int angle, int length, int width) {
        double radians = Math.toRadians(angle - 90);
        int x = (int)(width / 2 * Math.cos(radians));
        int y = (int)(width / 2 * Math.sin(radians));
        g.drawLine(width / 2, height / 2, width / 2 + x, height / 2 + y);
        radians = Math.toRadians(angle + 90);
        x = (int)(length * Math.cos(radians));
        y = (int)(length * Math.sin(radians));
        g.drawLine(width / 2 + x, height / 2 + y, width / 2 + x + width * x / Math.abs(x + y), height / 2 + y - width * y / Math.abs(x + y));
        g.drawLine(width / 2 + x, height / 2 + y, width / 2 + x - width * x / Math.abs(x + y), height / 2 + y + width * y / Math.abs(x + y));
    }

    public void setDate(Date date) {
        this.date = date;
        repaint();
    }
}

3. 创建时钟窗口

使用JFrame创建一个时钟窗口，并将时钟面板添加到窗口中，可以设置窗口的标题、大小等属性，代码如下所示：

public class ClockWindow extends JFrame {

    public ClockWindow() {
        setTitle("Clock");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        ClockPanel clockPanel = new ClockPanel(300, 300);
        add(clockPanel);
        pack();
        setLocationRelativeTo(null);
        setVisible(true);
        Timer timer = new Timer(10, e -> {
            clockPanel.setDate(new Date());
        });
        timer.start();
    }

    public static void main(String[] args) {
        new ClockWindow();
    }
}

这段代码创建了一个时钟窗口，窗口的标题为“Clock”，并将ClockPanel添加到窗口中。使用Timer定时更新时钟的显示。在每次更新时钟的时候，调用ClockPanel的setDate方法将当前时间传入，并调用repaint方法重新绘制时钟。

这是一个使用JFrame完成动态模拟时钟的例子，可以参考并修改代码，实现不同样式的时钟效果。