小钟表

来源：互联网发布：淘宝网怎么付款方式编辑：程序博客网时间：2024/04/28 14:19

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.event.*;

public class FirstSample{
    public static void main(String[] args){
        ClockFrame frame=new ClockFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

class ClockFrame extends JFrame{
    public ClockFrame(){
        setTitle("Clock");

        DocumentListener listener=new ClockFieldListener();
        JPanel panel=new JPanel();

        panel.add(new JLabel("Hours:"));
        hourField=new JTextField("12",3);
        panel.add(hourField);
        hourField.getDocument().addDocumentListener(listener);

        panel.add(new JLabel("Minutes:"));
        minuteField=new JTextField("00",3);
        panel.add(minuteField);
        minuteField.getDocument().addDocumentListener(listener);

        add(panel,BorderLayout.SOUTH);

        clock=new ClockPanel();
        add(clock,BorderLayout.CENTER);
        pack();
    }

    public void setClock(){
        try{
            int hours=Integer.parseInt(hourField.getText().trim());
            int minutes=Integer.parseInt(minuteField.getText().trim());
            clock.setTime(hours,minutes);
        }
        catch (NumberFormatException e){}
    }

    private JTextField hourField;
    private JTextField minuteField;
    private ClockPanel clock;

    private class ClockFieldListener implements DocumentListener{
        public void insertUpdate(DocumentEvent event) {setClock();}
        public void removeUpdate(DocumentEvent event) {setClock();}
        public void changedUpdate(DocumentEvent event) {}
    }
}

class ClockPanel extends JPanel{
    public ClockPanel(){
        setPreferredSize(new Dimension(2*RADIUS+1,2*RADIUS+1));
    }

    public void paintComponent(Graphics g){
        super.paintComponent(g);
        Graphics2D g2=(Graphics2D) g;

        Ellipse2D circle=new Ellipse2D.Double(0,0,2*RADIUS,2*RADIUS);
        g2.draw(circle);

        double hourAngle=Math.toRadians(90-360*minutes/(12*60));
        drawHand(g2,hourAngle,HOUR_HAND_LENGTH);

        double minuteAngle=Math.toRadians(90-360*minutes/60);
        drawHand(g2,minuteAngle,MINUTE_HAND_LENGTH);
    }

    public void drawHand(Graphics2D g2,double angle,double handLength){
        Point2D end=new Point2D.Double(RADIUS+handLength*Math.cos(angle),RADIUS-handLength*Math.sin(angle));
        Point2D center=new Point2D.Double(RADIUS,RADIUS);
        g2.draw(new Line2D.Double(center,end));
    }

    public void setTime(int h,int m){
        minutes=h*60+m;
        repaint();
    }

    private double minutes=0;
    private int RADIUS=100;
    private double MINUTE_HAND_LENGTH=0.8*RADIUS;
    private double HOUR_HAND_LENGTH=0.6*RADIUS;
}