java - 在java中将键盘归属于按钮

Question

好的，我已经有了一个用 java 构建的“小计算器”，我现在希望能够从我的键盘访问它(访问按钮)。

这是代码:

Gui类

package mainProgram;

import javax.swing.*;

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

public class Gui extends JFrame {
    final private static JButton numberButtons[] = new JButton[10];
    private JButton sum = new JButton("+");
    private JButton substract = new JButton("-");
    private JButton divide = new JButton("/");
    private JButton multiply = new JButton("*");
    private JButton sqrt = new JButton("√");
    private JButton square = new JButton("x^2");
    private JButton cubic = new JButton("x^3");
    private JButton percentage = new JButton("%");
    private JButton divideByOne = new JButton("1/x");
    private JButton C = new JButton("C");
    private JButton OK = new JButton("=");
    private JButton point = new JButton(".");
    private JButton plusMinus = new JButton("+-");
    private JTextArea output = new JTextArea();
    private JTextField inputOne = new JTextField();
    // WriteReadFunctions wrf = new WriteReadFunctions();
    functions fn = new functions();
    GuiUpdate gridBagConstr = new GuiUpdate();
    HandlerClass handler = new HandlerClass();

    public Gui() {
        super("Calculator");
        setLayout(new GridBagLayout());
        output.setEditable(false);
        output.setBackground(Color.RED);
        for (int i = 0; i <= numberButtons.length - 1; i++) {
            numberButtons[i] = new JButton(Integer.toString(i));
        }
        gridBagConstr.setConstrains("HORIZONTAL", 4, 1, 0, 0, 30);
        add(output, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 4, 1, 0, 1, 15);
        add(inputOne, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 0, 2, 0);
        add(divide, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 1, 2, 0);
        add(multiply, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 2, 2, 0);
        add(substract, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 3, 2, 0);
        add(sum, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 0, 3, 0);
        add(numberButtons[7], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 1, 3, 0);
        add(numberButtons[8], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 2, 3, 0);
        add(numberButtons[9], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 3, 3, 0);
        add(sqrt, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 0, 4, 0);
        add(numberButtons[4], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 1, 4, 0);
        add(numberButtons[5], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 2, 4, 0);
        add(numberButtons[6], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 3, 4, 0);
        add(square, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 0, 5, 0);
        add(numberButtons[1], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 1, 5, 0);
        add(numberButtons[2], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 2, 5, 0);
        add(numberButtons[3], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 3, 5, 0);
        add(cubic, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 0, 8, 0);
        add(numberButtons[0], gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 1, 8, 0);
        add(point, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 2, 8, 0);
        add(C, gridBagConstr.c);
        gridBagConstr.setConstrains("HORIZONTAL", 1, 1, 3, 8, 0);
        add(OK, gridBagConstr.c);
        inputOne.addActionListener(handler);
        divide.addActionListener(handler);
        multiply.addActionListener(handler);
        substract.addActionListener(handler);
        sum.addActionListener(handler);
        for (int i = 0; i <= numberButtons.length - 1; i++) {
            numberButtons[i].addActionListener(handler);
        }
        sqrt.addActionListener(handler);
        square.addActionListener(handler);
        cubic.addActionListener(handler);
        point.addActionListener(handler);
        C.addActionListener(handler);
        OK.addActionListener(handler);

    }

    public void eraseData() {
        fn.setA(0);
        inputOne.setText("");

    }

    public void saveInput() {
        if (fn.isNumeric(inputOne.getText())) {
            fn.setResult(Double.parseDouble(inputOne.getText()));
            output.setText(inputOne.getText());
        }
    }

HandlerClass 类

    private class HandlerClass implements ActionListener {
        String op;

        public void actionPerformed(ActionEvent e) {

                String x = e.getActionCommand();
                // if(fn.isNumeric(inputOne.getText()))
                // fn.setResult(Double.parseDouble(inputOne.getText()));
                switch (x) {
                case "0":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "1":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "2":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "3":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "4":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "5":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "6":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "7":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "8":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "9":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case ".":
                    inputOne.setText(inputOne.getText() + x);
                    break;
                case "/":
                    op = e.getActionCommand();
                    saveInput();
                    eraseData();
                    break;
                case "*":
                    op = e.getActionCommand();
                    saveInput();
                    eraseData();
                    break;
                case "-":
                    op = e.getActionCommand();
                    saveInput();
                    eraseData();
                    break;
                case "+":
                    op = e.getActionCommand();
                    saveInput();
                    eraseData();
                    break;
                case "√":
                    fn.sqrt(output.getText());
                    output.setText(Double.toString(fn.getResult()));
                    eraseData();
                    break;
                case "x^2":
                    fn.square(output.getText());
                    output.setText(Double.toString(fn.getResult()));
                    eraseData();
                    break;
                case "x^3":
                    fn.cubic(output.getText());
                    output.setText(Double.toString(fn.getResult()));
                    eraseData();
                    break;
                case "%":
                    break;
                case "1/x":
                    fn.divideByOne(output.getText());
                    output.setText(Double.toString(fn.getResult()));
                    eraseData();
                    break;
                case "C":
                    eraseData();
                    output.setText("");
                    fn.setResult(0);
                    break;
                case "=":
                    switch (op) {
                    case "/":
                        fn.divide(inputOne.getText(), fn.getResult());
                        output.setText(Double.toString(fn.getResult()));
                        eraseData();
                    case "*":
                        fn.multiply(inputOne.getText(), fn.getResult());
                        output.setText(Double.toString(fn.getResult()));
                        eraseData();
                    case "+":
                        fn.sum(inputOne.getText(), fn.getResult());
                        output.setText(Double.toString(fn.getResult()));
                        eraseData();
                    case "-":
                        fn.substract(inputOne.getText(), fn.getResult());
                        output.setText(Double.toString(fn.getResult()));
                        eraseData();
                    }
                    break;
                case "+-":
                    break;
                default:
                    break;
                }


        }

    }

}

类函数

package mainProgram;
import java.math.*;
import java.util.*;

    public class functions {

        private double a;
        private double result = 0;


        public boolean isNumeric (String x){
            try {
                Double.parseDouble(x);
                return true;
            } catch (NumberFormatException nfe) {}
            return false;

        }
        public double getNumber ( String x){
            if(isNumeric(x)){
                this.a= Double.parseDouble(x);}
            return a;
        }

        public double sum(String a, double b) {
            if(isNumeric(a)){
                double c = getNumber(a);
                result = b + c ; 
                return result;
            }else return b;

        }

        public double divide(String a , double b) {
            if(isNumeric(a)){
                double c = getNumber(a);

                result = b / c ; 
                return result;
            }else return b;

        }

        public double multiply(String a, double b) {
            if(isNumeric(a)){
                double c = getNumber(a);

                result = b * c ; 
                return result;
            }else return b;
        }

        public double substract(String a, double b) {
            if(isNumeric(a)){
                double c = getNumber(a);

                result = b - c ; 
                return result;
            }else return b;
        }
        public double sqrt(String a) {
            if(isNumeric(a)){
                double c = getNumber(a);
                result = Math.sqrt(c) ; 
                return result;
            }else return 0;
        }

        public double square(String a) {
            if(isNumeric(a)){
                double c = getNumber(a);
                result = c*c ; 
                return result;
            }else return 0;
        }

        public double cubic(String a) {
            if(isNumeric(a)){
                double c = getNumber(a);
                result = c*c*c ; 
                return result;
            }else return 0;
        }

        public double divideByOne(String a) {
            if(isNumeric(a)){
                double c = getNumber(a);
                result = 1/c ; 
                return result;
            }else return 0;
        }

        public double getA() {
            return a;
        }
        public void setA(double a) {
            this.a = a;
        }
        public double getResult() {
            return result;
        }
        public void setResult(double result) {
            this.result = result;
        }
}

类 GuiUpdate

package mainProgram;

import java.awt.GridBagConstraints;

public class GuiUpdate extends GridBagConstraints {

    GridBagConstraints c = new GridBagConstraints();

    public void setConstrains (String FILL, int gridwidth, int gridheight, int gridx, int gridy, int ipady ){
        if(FILL.toUpperCase().equals("HORIZONTAL")){
            this.c.fill = GridBagConstraints.HORIZONTAL;
            }else if(FILL.toUpperCase().equals("VERTICAL")){
                c.fill = GridBagConstraints.VERTICAL;
            }else if (FILL.toUpperCase().equals("BOTH")){
                c.fill = GridBagConstraints.BOTH;
            }else c.fill = GridBagConstraints.NONE;
            this.c.gridwidth = gridwidth;
            this.c.gridheight = gridheight;
            this.c.gridx = gridx;
            this.c.gridy = gridy;
            this.c.ipady = ipady;

    }

}

类主类

package mainProgram;
import javax.swing.JFrame;
public class mainClass {

    public static void main(String[] args) {

        Gui go = new Gui();
        go.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        go.setSize(230,350);
        go.setVisible(true);
    }
}

现在我想添加的是一个 KeyListener(或其他东西)，这样如果我按键盘上的数字或按(/* - +)计算器中具有该属性的按钮来激活他的监听器。我如何让自己被理解。我对这个 I/O 类和方法不是很熟悉，一些建议会很好，也许 1-2 个地方我可以阅读更多内容。

Answer 1

您将使用按键绑定(bind)。阅读 Swing 教程中关于 How to Use Key Bindings 的部分.

这是一个帮助您入门的简单示例:

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

public class ButtonCalculator extends JPanel
{
    private JButton[] buttons;
    private JTextField display;

    public ButtonCalculator()
    {
        Action numberAction = new AbstractAction()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                display.replaceSelection(e.getActionCommand());
            }
        };

        display = new JTextField();
        display.setEditable( false );
        display.setHorizontalAlignment(JTextField.RIGHT);

        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout( new GridLayout(0, 5) );
        buttons = new JButton[10];

        for (int i = 0; i < buttons.length; i++)
        {
            String text = String.valueOf(i);
            JButton button = new JButton( text );
            button.addActionListener( numberAction );
            buttons[i] = button;
            buttonPanel.add( button );

            //  Support Key Bindings

            KeyStroke pressed = KeyStroke.getKeyStroke(text);
            InputMap inputMap = button.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
            inputMap.put(pressed, text);
            button.getActionMap().put(text, numberAction);
        }

        setLayout( new BorderLayout() );
        add(display, BorderLayout.NORTH);
        add(buttonPanel, BorderLayout.SOUTH);
    }

    private static void createAndShowUI()
    {
        UIManager.put("Button.margin", new Insets(5, 10, 5, 10) );
        JFrame frame = new JFrame("Button Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add( new ButtonCalculator() );
        frame.setResizable( false );
        frame.pack();
        frame.setLocationByPlatform( true );
        frame.setVisible( true );
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowUI();
            }
        });
    }
}

该示例还展示了如何编写可由多个按钮共享的通用 ActionListener。