【课后练习分享】Java用户注册界面设计和求三角形面积的图形界面程序

java编程题（每日一练）：

问题一的答案代码如下：

问题一的运行截图如下：

问题二的答案代码如下：

问题二的运行截图如下：

java编程题（每日一练）：

1.设计一个用户注册的界面，包括用户名、密码输入框，性别单选按钮，表示爱好的篮球、足球、乒乓球复选框，表示学历的下拉列表框，“注册”按钮和“取消”按钮。

2.设计一个求三角形面积的图形界面程序，要求通过3个输入框输入3个边长，当单击“计算”按钮时，能够计算以输入的3个边长所形成的三角形的面积。要求能够判断输入的3个边长是否是数字，三个边长是否能够构成合法的三角形

问题一的答案代码如下：

Java 用户注册界面设计

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame("User Registration");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 300);
        frame.setLayout(new GridLayout(6, 2));

        JLabel nameLabel = new JLabel("Username:");
        JTextField nameField = new JTextField();
        JLabel passwordLabel = new JLabel("Password:");
        JPasswordField passwordField = new JPasswordField();

        JLabel genderLabel = new JLabel("Gender:");
        JRadioButton maleButton = new JRadioButton("Male");
        JRadioButton femaleButton = new JRadioButton("Female");
        ButtonGroup genderGroup = new ButtonGroup();
        genderGroup.add(maleButton);
        genderGroup.add(femaleButton);
        JPanel genderPanel = new JPanel();
        genderPanel.add(maleButton);
        genderPanel.add(femaleButton);

        JLabel hobbyLabel = new JLabel("Hobbies:");
        JCheckBox basketballBox = new JCheckBox("Basketball");
        JCheckBox footballBox = new JCheckBox("Football");
        JCheckBox pingpongBox = new JCheckBox("Ping Pong");
        JPanel hobbyPanel = new JPanel();
        hobbyPanel.add(basketballBox);
        hobbyPanel.add(footballBox);
        hobbyPanel.add(pingpongBox);

        JLabel educationLabel = new JLabel("Education:");
        String[] educationLevels = {"High School", "Associate", "Bachelor", "Master", "Doctor"};
        JComboBox<String> educationComboBox = new JComboBox<>(educationLevels);

        JButton registerButton = new JButton("Register");
        JButton cancelButton = new JButton("Cancel");

        frame.add(nameLabel);
        frame.add(nameField);
        frame.add(passwordLabel);
        frame.add(passwordField);
        frame.add(genderLabel);
        frame.add(genderPanel);
        frame.add(hobbyLabel);
        frame.add(hobbyPanel);
        frame.add(educationLabel);
        frame.add(educationComboBox);
        frame.add(registerButton);
        frame.add(cancelButton);

        registerButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String username = nameField.getText();
                String password = new String(passwordField.getPassword());
                String gender = maleButton.isSelected() ? "Male" : "Female";
                String hobbies = "";
                if (basketballBox.isSelected()) hobbies += "Basketball ";
                if (footballBox.isSelected()) hobbies += "Football ";
                if (pingpongBox.isSelected()) hobbies += "Ping Pong ";
                String education = (String) educationComboBox.getSelectedItem();
                JOptionPane.showMessageDialog(frame, "Username: " + username + "\nPassword: " + password + "\nGender: " + gender + "\nHobbies: " + hobbies + "\nEducation: " + education);
            }
        });

        cancelButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                nameField.setText("");
                passwordField.setText("");
                genderGroup.clearSelection();
                basketballBox.setSelected(false);
                footballBox.setSelected(false);
                pingpongBox.setSelected(false);
                educationComboBox.setSelectedIndex(0);
            }
        });

        frame.setVisible(true);
    }
}

问题一的运行截图如下：

问题二的答案代码如下：

求三角形面积的图形界面程序

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TriangleAreaCalculator {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Triangle Area Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 200);
        frame.setLayout(new GridLayout(5, 2));

        JLabel sideALabel = new JLabel("Side A:");
        JTextField sideAField = new JTextField();
        JLabel sideBLabel = new JLabel("Side B:");
        JTextField sideBField = new JTextField();
        JLabel sideCLabel = new JLabel("Side C:");
        JTextField sideCField = new JTextField();

        JButton calculateButton = new JButton("Calculate");
        JLabel resultLabel = new JLabel("Area:");

        frame.add(sideALabel);
        frame.add(sideAField);
        frame.add(sideBLabel);
        frame.add(sideBField);
        frame.add(sideCLabel);
        frame.add(sideCField);
        frame.add(calculateButton);
        frame.add(resultLabel);

        calculateButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    double a = Double.parseDouble(sideAField.getText());
                    double b = Double.parseDouble(sideBField.getText());
                    double c = Double.parseDouble(sideCField.getText());

                    if (isValidTriangle(a, b, c)) {
                        double s = (a + b + c) / 2;
                        double area = Math.sqrt(s * (s - a) * (s - b) * (s - c));
                        resultLabel.setText("Area: " + area);
                    } else {
                        resultLabel.setText("Invalid Triangle");
                    }
                } catch (NumberFormatException ex) {
                    resultLabel.setText("Please enter valid numbers");
                }
            }
        });

        frame.setVisible(true);
    }

    public static boolean isValidTriangle(double a, double b, double c) {
        return a + b > c && a + c > b && b + c > a;
    }
}