技術標籤：# Java題解

MyFrame:

package com.itheima;

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

public class MyFrame extends JFrame {
    JTextField text1, text2;
    JButton button;
    ButtonGroup buttonGroup;
    JRadioButton radio1,
 
 radio2;
    PoliceListen policeListen;


    public MyFrame() {
        init();
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    void init() {
        setLayout(new FlowLayout());
        text1 = new JTextField(16);
        text2 = new JTextField(16);
        button =
 
 new JButton("轉換");
        buttonGroup = new ButtonGroup();
        radio1 = new JRadioButton("大寫");
        radio2 = new JRadioButton("小寫");
        radio1.setActionCommand("大寫");
        radio2.setActionCommand("小寫");
        add(text1);
        buttonGroup.
 
add(radio1);//設定命令字串
        buttonGroup.add(radio2);
        add(button);
        add(radio1);
        add(radio2);
        add(text2);
        policeListen = new PoliceListen();
        button.addActionListener(policeListen);
    }

    private class PoliceListen implements ActionListener {


        @Override
        public void actionPerformed(ActionEvent e) {
            String command = buttonGroup.getSelection().getActionCommand();//獲取按鈕組中被挑選的元件命令字串
            boolean upper = command.equals("大寫");
            String s = text1.getText();
            if (upper) {
                text2.setText(s.toUpperCase());
            } else
                text2.setText(s.toLowerCase());
        }
    }
}

Main:

package com.itheima;
public class Main {
    public static void main(String[] args) {
        MyFrame myFrame = new MyFrame();
        myFrame.setBounds(100,100,240,160);
        myFrame.setTitle("字串大小寫轉換");

    }
}