Java中的快捷键（助记符）

Question

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

public class Calculator extends JFrame implements ActionListener{
    JLabel fval,sval;
    JTextField tf1,tf2;
    JButton add,subtract,multiply,divide,compute,reset; 
    String s="";
    JPanel jp = new JPanel();
    Calculator(){
        jp.setLayout(new GridLayout(5,2));
        fval=new JLabel("First Value: ");
        sval=new JLabel("Second Value: ");
        tf1=new JTextField();
        tf2=new JTextField();
        add=new JButton("ADD");
        subtract=new JButton("SUBTRACT");
        multiply=new JButton("MULTIPLY");
        divide=new JButton("DIVIDE");
        compute=new JButton("COMPUTE");
        reset=new JButton("RESET");
        jp.add(fval);
        jp.add(tf1);
        jp.add(sval);
        jp.add(tf2);
        jp.add(add);
        jp.add(subtract);
        jp.add(multiply);
        jp.add(divide);
        jp.add(compute);
        jp.add(reset);
        add.addActionListener(this);
        subtract.addActionListener(this);
        multiply.addActionListener(this);
        divide.addActionListener(this);
        compute.addActionListener(this);
        reset.addActionListener(this);
        this.setTitle("Calculator");
        this.setBounds(10,10,300,300);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setResizable(false);
        add(jp);
        
        //ADD
       Action addAction = new AbstractAction("ADD") {
 
            @Override
            public void actionPerformed(ActionEvent evt) {
                s="ADD";
            }
        };

        String key1 = "ADD";
        add.setAction(addAction);
        addAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_A);
        add.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(
                KeyStroke.getKeyStroke(KeyEvent.VK_A, KeyEvent.CTRL_DOWN_MASK), key1);
        add.getActionMap().put(key1, addAction);
        
        //SUBTRACT
        Action subAction = new AbstractAction("SUBTRACT") {
            @Override
            public void actionPerformed(ActionEvent evt) {
                s="SUBTRACT";
            }
        };
        
        String key2 = "SUBTRACT";
        subtract.setAction(subAction);
        subAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_S);
        subtract.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(
                KeyStroke.getKeyStroke(KeyEvent.VK_S, KeyEvent.CTRL_DOWN_MASK), key2);     
        subtract.getActionMap().put(key2, subAction);
        
        //MULTIPLY
         Action mulAction = new AbstractAction("MULTIPLY") {
            @Override
            public void actionPerformed(ActionEvent evt) {
                s="MULTIPLY";
            }
        };
        
        String key3 = "MULTIPLY";
        multiply.setAction(mulAction);
        mulAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_M);
        multiply.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(
                KeyStroke.getKeyStroke(KeyEvent.VK_M, KeyEvent.CTRL_DOWN_MASK), key3);     
        multiply.getActionMap().put(key3, mulAction);
        
        //DIVIDE
        Action divAction = new AbstractAction("DIVIDE") {
            @Override
            public void actionPerformed(ActionEvent evt) {
                s="DIVIDE";
            }
        };
        
        String key4 = "DIVIDE";
        divide.setAction(divAction);
        divAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_D);
        divide.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(
                KeyStroke.getKeyStroke(KeyEvent.VK_D, KeyEvent.CTRL_DOWN_MASK), key4);     
        divide.getActionMap().put(key4, divAction);
        
    }
    
    public void Add(double n1,double n2){
        JOptionPane.showMessageDialog(this, +(n1+n2), "Answer", JOptionPane.INFORMATION_MESSAGE);
    }
    public void Subtract(double n1,double n2){
        JOptionPane.showMessageDialog(this, +(n1-n2), "Answer", JOptionPane.INFORMATION_MESSAGE);
    }
    public void Multiply(double n1,double n2){
        JOptionPane.showMessageDialog(this, +(n1*n2), "Answer", JOptionPane.INFORMATION_MESSAGE);
    }
    public void Divide(double n1,double n2){
        JOptionPane.showMessageDialog(this, +(n1/n2), "Answer", JOptionPane.INFORMATION_MESSAGE);
    }
    
    @Override
    public void actionPerformed(ActionEvent e) {
        String in=e.getActionCommand();
        if(in.equals("COMPUTE")){
        try {
            double n1=Double.parseDouble(tf1.getText());
            double n2=Double.parseDouble(tf2.getText());
        
            if(s.equals("ADD"))
                Add(n1,n2);
            else if(s.equals("SUBTRACT"))
                Subtract(n1,n2);
            else if(s.equals("MULTIPLY"))
                Multiply(n1,n2);
            else if(s.equals("DIVIDE"))
                Divide(n1,n2);
            else if(in.equals("RESET")){
                tf1.setText("");
                tf2.setText("");
                s="";
            }else
            {
                s=in;
         }
        }
        catch (NumberFormatException e1) {
            compute.setSelected(true);
        JOptionPane.showMessageDialog(this, "Math Error.", "Warning", JOptionPane.INFORMATION_MESSAGE);
    }
    }       
};
    
    public static void main(String[] args) {
        new Calculator();
    }  
}

提前感谢！

Answer 1

我只需要为计算，重置和退出按钮放快捷键。

我想你把“助记符”和“加速器”搞混了。

当聚焦组件时调用“助记符”。通过使用“alt”键加上按钮上文本的下划线字符来调用操作。