package test;

import java.awt.Button;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Label;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class Round extends Frame implements ActionListener {
    TextField t1, t2, t3, t4;
    Button b1;
    Button btnExit;

    public Round() {
        setLayout(new FlowLayout());
        t1 = new TextField(20);
        t1.setBackground(Color.orange);
        t2 = new TextField(20);
        t2.setBackground(Color.orange);
        t3 = new TextField(20);
        t3.setBackground(Color.orange);
        t4 = new TextField(20);
        t4.setBackground(Color.orange);
        b1 = new Button("计算");
        btnExit = new Button("退出");
        add(new Label("输入圆的半径:"));
        add(t1);
        add(new Label("得出圆的直径:"));
        add(t2);
        add(new Label("得出圆的面积:"));
        add(t3);
        add(new Label("得出圆的周长:"));
        add(t4);
        add(b1);
        add(btnExit);
        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        b1.addActionListener(this);
        btnExit.addActionListener(this);
        setVisible(true);
        setBounds(200, 200, 200, 300);
        validate();
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == b1) {
            double temp, r, a, c;
            temp = Float.parseFloat(t1.getText());
            r = 2 * temp;
            a = 3.14 * temp * temp;
            c = 2 * 3.14 * temp;
            t2.setText(String.valueOf(r));
            t3.setText(String.valueOf(a));
            t4.setText(String.valueOf(c));
        }
        if (e.getSource() == btnExit) {
            System.exit(0);
        }
    }

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