让计算器上的按钮具有互动性的最好方法是什么，这样它们就可以进行加法，减法等操作

Question

我想做一个有趣的小计算器项目，用Java Swing API测试我新的GUI知识。我创建了GUI，但是缺少一个关键部分:数学!我的问题是，我如何为这些按钮添加功能?简单来说:当用户单击按钮时，我如何让按钮向文本框(2+2)添加一些内容，然后让系统实际将数字加在一起并显示给用户?

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;

public class basicCalculatorDesign {
    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            } 
            catch (Exception e) {
            }
        basicCalculatorDesign calc = new basicCalculatorDesign();
        calc.start();
    }
    public void start() {
        JFrame frame = new JFrame();
        JPanel panel = new JPanel();
        JButton one = new JButton("1");
        JButton two = new JButton("2");
        JButton three = new JButton("3");
        JButton four = new JButton("4");
        JButton five = new JButton("5");
        JButton six = new JButton("6");
        JButton seven = new JButton("7");
        JButton eight = new JButton("8");
        JButton nine = new JButton("9");
        JButton zero = new JButton("0");
        JButton plus = new JButton("+");
        JButton minus = new JButton("-");
        JButton divide = new JButton("/");
        JButton multiply = new JButton("*");
        JButton sqrt = new JButton("SqRt");
        JButton percentage = new JButton("%");
        JButton equals = new JButton("=");
        JTextField input = new JTextField();
        JLabel label = new JLabel("Basic Calculator");
        frame.getContentPane().add(BorderLayout.NORTH, label);
        frame.getContentPane().add(BorderLayout.SOUTH, input);
        panel.setBackground(Color.BLUE);
        panel.setLayout(new GridBagLayout());
        JPanel panel2 = new JPanel();
        panel2.setLayout(new BoxLayout(panel2, BoxLayout.Y_AXIS));
        panel2.setBackground(Color.RED);
        frame.getContentPane().add(BorderLayout.EAST, panel2);
        frame.getContentPane().add(BorderLayout.CENTER, panel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.setSize(210, 260);

        GridBagConstraints right = new GridBagConstraints();
        right.anchor = GridBagConstraints.WEST;
        GridBagConstraints left = new GridBagConstraints();
        left.anchor = GridBagConstraints.EAST;
        GridBagConstraints middle = new GridBagConstraints();
        middle.anchor = GridBagConstraints.CENTER;
        right.gridwidth = GridBagConstraints.REMAINDER;
        right.fill = GridBagConstraints.HORIZONTAL;
        // add buttons
        panel.add(one, left);
        panel.add(two, middle);
        panel.add(three, right);
        panel.add(four, left);
        panel.add(five, middle);
        panel.add(six, right);
        panel.add(seven, left);
        panel.add(eight, middle);
        panel.add(nine, right);
        panel.add(zero, right);
        panel2.add(equals);
        panel2.add(plus);
        panel2.add(minus);
        panel2.add(divide);
        panel2.add(multiply);
        panel2.add(sqrt);
        panel2.add(percentage);
    }
}

Answer 1

是否可以将其实现到一个内部类中，然后在不同的按钮上多次使用该内部类。

你可以为你的数字(0-9)按钮使用相同的Action (ActionListener)。比如:

public void actionPerformed(ActionEvent e)
{
    JButton source = (JButton)e.getSource();
    display.replaceSelection( source.getActionCommand() );
}

，其中"display"是显示数字和结果的textField。这段代码将把被点击的按钮的数字附加到显示中。

对于其他按钮，您应该创建单独的操作，因为它们执行不同的功能。