具有击键响应的 Java 计算器 [英] Java Calculator with Keystroke response

问题描述

所以我写了这个脚本；这是我找到并拼凑起来的计算器的大杂烩.

So I have this script written up; it's kind-of a hodgepodge of a calculator I found and pieced together.

KeyListener 来自 Java - oracle - .com 网站.附带说明一下，我对此非常陌生，不知道我在做什么.

The KeyListener is from the Java - oracle - .com website. On a side note, I'm extremely new to this and have no clue what I'm doing.

我正在尝试使用 KeyListener 来允许击键使计算器工作，以便不必单击输入；目前脚本可以编译，但无法输入输入...我这样做对吗?

I'm attempting to use the KeyListener to allow the keystrokes to make the calculator work, so that the input doesn't have to be clicked; currently the script compiles but the input cannot be typed in... Am I even doing this right?

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;

public class Calculator extends JFrame implements KeyListener, ActionListener {

JPanel[] row = new JPanel[5];
JButton[] button = new JButton[19];
String[] buttonstring = {"7", "8", "9", "+",
                         "4", "5", "6", "-",
                         "1", "2", "3", "*",
                         ".", "/", "C", "SR",
                         "+/-", "=", "0"};
int[] dimW = {300,45,100,90};
int[] dimH = {35, 40};
Dimension displayDimension = new Dimension(dimW[0], dimH[0]);
Dimension regularDimension = new Dimension(dimW[1], dimH[1]);
Dimension rColumnDimension = new Dimension(dimW[2], dimH[1]);
Dimension zeroButDimension = new Dimension(dimW[3], dimH[1]);
boolean[] function = new boolean[4];
double[] temporary = {0, 0};
JTextArea display = new JTextArea(1,20);

Font font = new Font("Times new Roman", Font.BOLD, 14);
JTextArea displayArea;
JTextField typingArea;
static final String newline = System.getProperty("line.separator");

    //Uncomment this if you wish to turn off focus
    //traversal.  The focus subsystem consumes
    //focus traversal keys, such as Tab and Shift Tab.
    //If you uncomment the following line of code, this
    //disables focus traversal and the Tab events will
    //become available to the key event listener.
    //typingArea.setFocusTraversalKeysEnabled(false);


Calculator() {
    super("Calculator");
    setDesign();
    setSize(380, 250);
    setResizable(false);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    GridLayout grid = new GridLayout(5,5);
    setLayout(grid);

    for(int i = 0; i < 4; i++)
        function[i] = false;

    FlowLayout f1 = new FlowLayout(FlowLayout.CENTER);
    FlowLayout f2 = new FlowLayout(FlowLayout.CENTER,1,1);
    for(int i = 0; i < 5; i++)
        row[i] = new JPanel();
    row[0].setLayout(f1);
    for(int i = 1; i < 5; i++)
        row[i].setLayout(f2);

    for(int i = 0; i < 19; i++) {
        button[i] = new JButton();
        button[i].setText(buttonstring[i]);
        button[i].setFont(font);
        button[i].addActionListener(this);
    }

    display.setFont(font);
    display.setEditable(false);
    display.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
    display.setPreferredSize(displayDimension);
    for(int i = 0; i < 14; i++)
        button[i].setPreferredSize(regularDimension);
    for(int i = 14; i < 18; i++)
        button[i].setPreferredSize(rColumnDimension);
    button[18].setPreferredSize(zeroButDimension);

    row[0].add(display);
    add(row[0]);

    for(int i = 0; i < 4; i++)
        row[1].add(button[i]);
    row[1].add(button[14]);
    add(row[1]);

    for(int i = 4; i < 8; i++)
        row[2].add(button[i]);
    row[2].add(button[15]);
    add(row[2]);

    for(int i = 8; i < 12; i++)
        row[3].add(button[i]);
    row[3].add(button[16]);
    add(row[3]);

    row[4].add(button[18]);
    for(int i = 12; i < 14; i++)
        row[4].add(button[i]);
    row[4].add(button[17]);
    add(row[4]);

    setVisible(true);
}



public void clear() {
    try {
        display.setText("");
        for(int i = 0; i < 4; i++)
            function[i] = false;
        for(int i = 0; i < 2; i++)
            temporary[i] = 0;
    } catch(NullPointerException e) {  
    }
}

public void getSqrt() {
    try {
        double value = Math.sqrt(Double.parseDouble(display.getText()));
        display.setText(Double.toString(value));
    } catch(NumberFormatException e) {
    }
}

public void getPosNeg() {
    try {
        double value = Double.parseDouble(display.getText());
        if(value != 0) {
            value = value * (-1);
            display.setText(Double.toString(value));
        }
        else {
        }
    } catch(NumberFormatException e) {
    }
}

public void getResult() {
    double result = 0;
    temporary[1] = Double.parseDouble(display.getText());
    String temp0 = Double.toString(temporary[0]);
    String temp1 = Double.toString(temporary[1]);
    try {
        if(temp0.contains("-")) {
            String[] temp00 = temp0.split("-", 2);
            temporary[0] = (Double.parseDouble(temp00[1]) * -1);
        }
        if(temp1.contains("-")) {
            String[] temp11 = temp1.split("-", 2);
            temporary[1] = (Double.parseDouble(temp11[1]) * -1);
        }
    } catch(ArrayIndexOutOfBoundsException e) {
    }
    try {
        if(function[2] == true)
            result = temporary[0] * temporary[1];
        else if(function[3] == true)
            result = temporary[0] / temporary[1];
        else if(function[0] == true)
            result = temporary[0] + temporary[1];
        else if(function[1] == true)
            result = temporary[0] - temporary[1];
        display.setText(Double.toString(result));
        for(int i = 0; i < 4; i++)
            function[i] = false;
    } catch(NumberFormatException e) {
    }
}

public final void setDesign() {
    try {
        UIManager.setLookAndFeel(
                "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
    } catch(Exception e) {   
    }
}

@Override
public void actionPerformed(ActionEvent ae) {
    if(ae.getSource() == button[0])
        display.append("7");
    if(ae.getSource() == button[1])
        display.append("8");
    if(ae.getSource() == button[2])
        display.append("9");
    if(ae.getSource() == button[3]) {
        //add function[0]
        temporary[0] = Double.parseDouble(display.getText());
        function[0] = true;
        display.setText("");
    }
    if(ae.getSource() == button[4])
        display.append("4");
    if(ae.getSource() == button[5])
        display.append("5");
    if(ae.getSource() == button[6])
        display.append("6");
    if(ae.getSource() == button[7]) {
        //subtract function[1]
        temporary[0] = Double.parseDouble(display.getText());
        function[1] = true;
        display.setText("");
    }
    if(ae.getSource() == button[8])
        display.append("1");
    if(ae.getSource() == button[9])
        display.append("2");
    if(ae.getSource() == button[10])
        display.append("3");
    if(ae.getSource() == button[11]) {
        //multiply function[2]
        temporary[0] = Double.parseDouble(display.getText());
        function[2] = true;
        display.setText("");
    }
    if(ae.getSource() == button[12])
        display.append(".");
    if(ae.getSource() == button[13]) {
        //divide function[3]
        temporary[0] = Double.parseDouble(display.getText());
        function[3] = true;
        display.setText("");
    }
    if(ae.getSource() == button[14])
        clear();
    if(ae.getSource() == button[15])
        getSqrt();
    if(ae.getSource() == button[16])
        getPosNeg();
    if(ae.getSource() == button[17])
        getResult();
    if(ae.getSource() == button[18])
        display.append("0");
}

public void contentPane() {
 typingArea = new JTextField(20);
    typingArea.addKeyListener(this);
   displayArea = new JTextArea();
       displayArea.setEditable(false);
       JScrollPane scrollPane = new JScrollPane(displayArea);
       scrollPane.setPreferredSize(new Dimension(375, 125));

       getContentPane().add(typingArea, BorderLayout.PAGE_START);  
       getContentPane().add(scrollPane, BorderLayout.CENTER); 


}

public void keyTyped(KeyEvent e) {
    displayInfo(e, "KEY TYPED: ");
}

/** Handle the key pressed event from the text field. */
public void keyPressed(KeyEvent e) {
    displayInfo(e, "KEY PRESSED: ");
}

/** Handle the key released event from the text field. */
public void keyReleased(KeyEvent e) {
    displayInfo(e, "KEY RELEASED: ");
}

/** Handle the button click. */
public void ActionPerformed(ActionEvent e) {
    //Clear the text components.
    displayArea.setText("");
    typingArea.setText("");

    //Return the focus to the typing area.
    typingArea.requestFocusInWindow();
}

private void displayInfo(KeyEvent e, String keyStatus){

    //You should only rely on the key char if the event
    //is a key typed event.
    int id = e.getID();
    String keyString;
    if (id == KeyEvent.KEY_TYPED) {
        char c = e.getKeyChar();
        keyString = "key character = '" + c + "'";
    }  else {
        int keyCode = e.getKeyCode();
        keyString = "key code = " + keyCode
                + " ("
                + KeyEvent.getKeyText(keyCode)
                + ")";
    }

    int modifiersEx = e.getModifiersEx();
    String modString = "extended modifiers = " + modifiersEx;
    String tmpString = KeyEvent.getModifiersExText(modifiersEx);
    if (tmpString.length() > 0) {
        modString += " (" + tmpString + ")";
    } else {
        modString += " (no extended modifiers)";
    }

    String actionString = "action key? ";
    if (e.isActionKey()) {
        actionString += "YES";
    } else {
        actionString += "NO";
    }

    String locationString = "key location: ";
    int location = e.getKeyLocation();
    if (location == KeyEvent.KEY_LOCATION_STANDARD) {
        locationString += "standard";
    } else if (location == KeyEvent.KEY_LOCATION_LEFT) {
        locationString += "left";
    } else if (location == KeyEvent.KEY_LOCATION_RIGHT) {
        locationString += "right";
    } else if (location == KeyEvent.KEY_LOCATION_NUMPAD) {
        locationString += "numpad";
    } else { // (location == KeyEvent.KEY_LOCATION_UNKNOWN)
        locationString += "unknown";
    }

    displayArea.append(keyStatus + newline
            + "    " + keyString + newline
            + "    " + modString + newline
            + "    " + actionString + newline
            + "    " + locationString + newline);
    displayArea.setCaretPosition(displayArea.getDocument().getLength()); 

}
public static void main(String[] arguments) {
Calculator c = new Calculator();
}
}

推荐答案

这里有一些东西可以帮助您入门.它展示了如何使用键绑定(而不是 KeyListener).

Here is something to get you started. It shows how to use Key Bindings (instead of a KeyListener).

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

public class CalculatorPanel extends JPanel
{
    private JTextField display;

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

        setLayout( new BorderLayout() );

        display = new JTextField();
        display.setEditable( false );
        display.setHorizontalAlignment(JTextField.RIGHT);
        add(display, BorderLayout.NORTH);

        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout( new GridLayout(0, 5) );
        add(buttonPanel, BorderLayout.CENTER);

        for (int i = 0; i < 10; i++)
        {
            String text = String.valueOf(i);
            JButton button = new JButton( text );
            button.addActionListener( numberAction );
            button.setBorder( new LineBorder(Color.BLACK) );
            button.setPreferredSize( new Dimension(50, 50) );
            buttonPanel.add( button );

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

    private static void createAndShowUI()
    {
//      UIManager.put("Button.margin", new Insets(10, 10, 10, 10) );

        JFrame frame = new JFrame("Calculator Panel");
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.add( new CalculatorPanel() );
        frame.pack();
        frame.setLocationRelativeTo( null );
        frame.setVisible(true);
    }

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

阅读 Swing 教程中关于如何使用键绑定 有关 Key Bindings 的更多信息以及为什么应该使用它们而不是 KeyListener

Read the section from the Swing tutorial on How to Use Key Bindings for more information about Key Bindings and why they should be used instead of a KeyListener

这篇关于具有击键响应的 Java 计算器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！