JAVA_用Swing做一个计算器

答案:3 悬赏:70

解决时间 2021-01-11 06:34

提问者网友：佞臣
2021-01-10 14:40

JAVA_用Swing做一个计算器

最佳答案

二级知识专家网友：杯酒困英雄
2021-01-10 16:04

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

public class JCalculator extends JFrame implements ActionListener {
private static final long serialVersionUID = -169068472193786457L;
private class WindowCloser extends WindowAdapter {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
}

int i;
private final String[] str = { "7", "8", "9", "/", "4", "5", "6", "*", "1",
"2", "3", "-", ".", "0", "=", "+" };
// 建立按钮
JButton[] buttons = new JButton[str.length];
// 撤销重置
JButton reset = new JButton("CE");
// 建立文本域显示结果
JTextField display = new JTextField("0");

public JCalculator() {
super("Calculator");
// 添加一个面板
JPanel panel1 = new JPanel(new GridLayout(4, 4));
// panel1.setLayout(new GridLayout(4,4));
for (i = 0; i < str.length; i++) {
buttons[i] = new JButton(str[i]);
panel1.add(buttons[i]);
}
JPanel panel2 = new JPanel(new BorderLayout());
// panel2.setLayout(new BorderLayout());
panel2.add("Center", display);
panel2.add("East", reset);
// JPanel panel3 = new Panel();
getContentPane().setLayout(new BorderLayout());
getContentPane().add("North", panel2);
getContentPane().add("Center", panel1);
// 添加操作动作的监听器.
for (i = 0; i < str.length; i++)
buttons[i].addActionListener(this);
// 为重置按钮添加监听器
reset.addActionListener(this);
display.addActionListener(this);
// The "close" button "X".
addWindowListener(new WindowCloser());
// Initialize the window size.
setSize(800, 800);
// Show the window.
// show(); Using show() while JDK version is below 1.5.
setVisible(true);
// Fit the certain size.
pack();
}

public void actionPerformed(ActionEvent e) {
Object target = e.getSource();
String label = e.getActionCommand();
if (target == reset)
handleReset();
else if ("0123456789.".indexOf(label) > 0)
handleNumber(label);
else
handleOperator(label);
}
// Is the first digit pressed?
boolean isFirstDigit = true;

public void handleNumber(String key) {
if (isFirstDigit)
display.setText(key);
else if ((key.equals(".")) && (display.getText().indexOf(".") < 0))
display.setText(display.getText() + ".");
else if (!key.equals("."))
display.setText(display.getText() + key);
isFirstDigit = false;
}

public void handleReset() {
display.setText("0");
isFirstDigit = true;
operator = "=";
}

double number = 0.0;
String operator = "=";

public void handleOperator(String key) {
if (operator.equals("+"))
number += Double.valueOf(display.getText());
else if (operator.equals("-"))
number -= Double.valueOf(display.getText());
else if (operator.equals("*"))
number *= Double.valueOf(display.getText());
else if (operator.equals("/"))
number /= Double.valueOf(display.getText());
else if (operator.equals("="))
number = Double.valueOf(display.getText());
display.setText(String.valueOf(number));
operator = key;
isFirstDigit = true;
}

public static void main(String[] args) {
new JCalculator();
}
}

全部回答

1楼网友：西岸风
2021-01-10 17:42

你可以看看，希望能帮到你。

2楼网友：神的生死簿
2021-01-10 16:38

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

public class Calculator extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;
    private JTextField txtResult;
    private JButton btnZero, btnOne, btnTwo, btnThree, btnFour, btnFive,
            btnSix, btnSeven, btnEight, btnNine, btnPlus, btnMinus, btnTimes,
            btnDivided, btnEqual, btnPoint, btnC, btnCE, btnSqrt, btnPlusMinus;
    int z;
    double x, y;
    StringBuffer str;

    public Calculator() {
        super("计算器");
        this.setSize(311, 231);
        this.setLocation(300, 300);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        this.setLayout(new GridLayout(1, 1));// 网格布局
        JPanel panel = new JPanel(new GridLayout(6, 1));// 面板网格布局6行1列
        this.add(panel);

        txtResult = new JTextField("0");
        Color BackColor = new Color(255, 255, 255);
        Color ForeColor = new Color(0, 0, 0);
        txtResult.setBackground(BackColor);
        txtResult.setForeground(ForeColor);

        panel.add(txtResult);
        txtResult.setHorizontalAlignment(JTextField.RIGHT);
        txtResult.setEnabled(false);
        // text.setEnabled(true);

        JPanel panel_1 = new JPanel(new GridLayout(1, 4));
        panel.add(panel_1);

        btnSqrt = new JButton("sqrt");
        panel_1.add(btnSqrt);
        btnSqrt.addActionListener(this);
        btnPlusMinus = new JButton("+/-");
        panel_1.add(btnPlusMinus);
        btnPlusMinus.addActionListener(this);
        btnCE = new JButton("CE");
        panel_1.add(btnCE);
        btnCE.addActionListener(this);
        btnC = new JButton("C");
        panel_1.add(btnC);
        btnC.addActionListener(this);

        JPanel panel_2 = new JPanel(new GridLayout(1, 4));
        panel.add(panel_2);

        btnSeven = new JButton("7");
        panel_2.add(btnSeven);
        btnSeven.addActionListener(this);
        btnEight = new JButton("8");
        panel_2.add(btnEight);
        btnEight.addActionListener(this);
        btnNine = new JButton("9");
        panel_2.add(btnNine);
        btnNine.addActionListener(this);
        btnDivided = new JButton("/");
        panel_2.add(btnDivided);
        btnDivided.addActionListener(this);

        JPanel panel_3 = new JPanel(new GridLayout(1, 4));
        panel.add(panel_3);

        btnFour = new JButton("4");
        panel_3.add(btnFour);
        btnFour.addActionListener(this);
        btnFive = new JButton("5");
        panel_3.add(btnFive);
        btnFive.addActionListener(this);
        btnSix = new JButton("6");
        panel_3.add(btnSix);
        btnSix.addActionListener(this);
        btnTimes = new JButton("*");
        panel_3.add(btnTimes);
        btnTimes.addActionListener(this);

        JPanel panel_4 = new JPanel(new GridLayout(1, 4));
        panel.add(panel_4);

        btnOne = new JButton("1");
        panel_4.add(btnOne);
        btnOne.addActionListener(this);
        btnTwo = new JButton("2");
        panel_4.add(btnTwo);
        btnTwo.addActionListener(this);
        btnThree = new JButton("3");
        panel_4.add(btnThree);
        btnThree.addActionListener(this);
        btnMinus = new JButton("-");
        panel_4.add(btnMinus);
        btnMinus.addActionListener(this);

        JPanel panel_5 = new JPanel(new GridLayout(1, 4));
        panel.add(panel_5);

        btnZero = new JButton("0");
        panel_5.add(btnZero);
        btnZero.addActionListener(this);
        btnPoint = new JButton(".");
        panel_5.add(btnPoint);
        btnPoint.addActionListener(this);
        btnEqual = new JButton("=");
        panel_5.add(btnEqual);
        btnEqual.addActionListener(this);
        btnPlus = new JButton("+");
        panel_5.add(btnPlus);
        btnPlus.addActionListener(this);

        str = new StringBuffer();

        this.setVisible(true);

    }

    public void windowClosing(WindowEvent a) {
        System.exit(0);
    }

    public void actionPerformed(ActionEvent e) {

        try {
            if (e.getSource() == btnC) {
                txtResult.setText("0");
                str.setLength(0);
            } else if (e.getSource() == btnCE) {
                txtResult.setText("0.");
                str.setLength(0);
            } else if (e.getSource() == btnPlusMinus) {
                x = Double.parseDouble(txtResult.getText().trim());
                txtResult.setText("" + (-x));
            }

            else if (e.getSource() == btnPlus) {
                x = Double.parseDouble(txtResult.getText().trim());
                str.setLength(0);
                y = 0d;
                z = 1;
            } else if (e.getSource() == btnMinus) {
                x = Double.parseDouble(txtResult.getText().trim());
                str.setLength(0);
                y = 0d;
                z = 2;
            } else if (e.getSource() == btnTimes) {
                x = Double.parseDouble(txtResult.getText().trim());
                str.setLength(0);
                y = 0d;
                z = 3;
            } else if (e.getSource() == btnDivided) {
                x = Double.parseDouble(txtResult.getText().trim());
                str.setLength(0);
                y = 0d;
                z = 4;
            } else if (e.getSource() == btnEqual) {
                str.setLength(0);
                switch (z) {
                case 1:
                    txtResult.setText("" + (x + y));
                    break;
                case 2:
                    txtResult.setText("" + (x - y));
                    break;
                case 3:
                    txtResult.setText("" + (x * y));
                    break;
                case 4:
                    txtResult.setText("" + (x / y));
                    break;
                }
            }

            else if (e.getSource() == btnPoint) {
                if (txtResult.getText().trim().indexOf('.') != -1)// 判断字符串中是否已经包含了小数点
                {

                } else// 如果没数点有小
                {
                    if (txtResult.getText().trim().equals("0"))// 如果初时显示为0
                    {
                        str.setLength(0);
                        txtResult.setText((str.append("0"
                                + e.getActionCommand())).toString());
                    } else if (txtResult.getText().trim().equals(""))// 如果初时显示为空则不做任何操作
                    {
                    } else {
                        txtResult.setText(str.append(e.getActionCommand())
                                .toString());
                    }
                }

                y = 0d;
            }

            else if (e.getSource() == btnSqrt)// 求平方根
            {
                x = Double.parseDouble(txtResult.getText().trim());
                txtResult.setText("数字格式异常");
                if (x < 0)
                    txtResult.setText("负数没有平方根");
                else
                    txtResult.setText("" + Math.sqrt(x));
                str.setLength(0);
                y = 0d;
            }

            else if (e.getSource() == btnZero)// 如果选择的是"0"这个数字键
            {
                if (txtResult.getText().trim().equals("0"))// 如果显示屏显示的为零不做操作
                {
                } else {
                    txtResult.setText(str.append(e.getActionCommand())
                            .toString());
                    y = Double.parseDouble(txtResult.getText().trim());
                }
            }

            else// 其他的数字键
            {
                txtResult.setText(str.append(e.getActionCommand()).toString());
                y = Double.parseDouble(txtResult.getText().trim());
            }
        } catch (NumberFormatException ae) {
            txtResult.setText("数字格式异常");
        } catch (StringIndexOutOfBoundsException ae) {
            txtResult.setText("字符串索引越界");
        }

    }

    public static void main(String arg[]) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception e) {
            e.printStackTrace();
        }
        new Calculator();
    }

}

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