Java简易计算器

package ren.redface.demo;

import java.awt.*;
import java.awt.event.*;

public class Jisuanqi {

    public static void main(String[] args) {
        new MyFrame("计算器");
    }

}

class MyFrame extends Frame {
    private static final long serialVersionUID = 1L;
    private TextArea ta, tb;

    public MyFrame(String title) {
        super(title);
        SetTextAreas();
        SetButtonArea();
        SetMainFram();
    }

    private void SetButtonArea() {

        addButton("7", 33, 28, 20, 178);
        addButton("8", 33, 28, 58, 178);
        addButton("9", 33, 28, 96, 178);
        addButton("/", 33, 28, 134, 178);
        addButton("%", 33, 28, 172, 178);

        addButton("4", 33, 28, 20, 210);
        addButton("5", 33, 28, 58, 210);
        addButton("6", 33, 28, 96, 210);
        addButton("*", 33, 28, 134, 210);
        addButton("1/x", 33, 28, 172, 210);

        addButton("1", 33, 28, 20, 242);
        addButton("2", 33, 28, 58, 242);
        addButton("3", 33, 28, 96, 242);
        addButton("-", 33, 28, 134, 242);

        addButton("0", 71, 28, 20, 274);
        addButton(".", 33, 28, 96, 274);
        addButton("+", 33, 28, 134, 274);

        addButton("=", 33, 60, 172, 242);
    }

    double m, n;
    String k;
    boolean flag = true;
    boolean flag2 = false;

    private void addButton(String string, int i, int j, int x, int y) {
        final Button b = new Button(string);
        b.setLocation(x, y);
        b.setSize(i, j);
        b.setFont(new Font("标楷体", Font.BOLD, 15));
        b.setBackground(Color.pink);
        b.setForeground(Color.darkGray);
        b.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                counts();

            }

            private void counts() {
                if (ta.getText().equals("") && (b.getActionCommand().equals("+") || b.getActionCommand().equals("-")
                        || b.getActionCommand().equals("*") || b.getActionCommand().equals("/")
                        || b.getActionCommand().equals("%") || b.getActionCommand().equals("1/x")
                        || b.getActionCommand().equals("="))) {

                } else if (ta.getText().equals(".") && (b.getActionCommand().equals("+")
                        || b.getActionCommand().equals("-") || b.getActionCommand().equals("*")
                        || b.getActionCommand().equals("/") || b.getActionCommand().equals("%")
                        || b.getActionCommand().equals("1/x") || b.getActionCommand().equals("="))) {

                } else {
                    if (b.getActionCommand().equals("+") || b.getActionCommand().equals("-")
                            || b.getActionCommand().equals("*") || b.getActionCommand().equals("%")
                            || b.getActionCommand().equals("1/x") || b.getActionCommand().equals("/")) {
                        if (flag2 = true) {
                            flag2 = false;
                        }
                        if (flag) {
                            n = new Double(ta.getText()).doubleValue();
                            flag = false;
                        } else {
                            if (k == "=") {

                            } else {
                                m = new Double(ta.getText()).doubleValue();
                                if (k == "-") {
                                    if (n == 0)
                                        n = m;
                                    else
                                        n = n - m;
                                } else if (k == "+") {
                                    if (n == 0)
                                        n = m;
                                    else
                                        n = n + m;
                                } else if (k == "*") {
                                    if (n == 0)
                                        n = m;
                                    else
                                        n = n * m;
                                } else if (k == "%") {
                                    if (n == 0)
                                        n = m;
                                    else
                                        m = m * 100;
                                } else if (k == "1/x") {
                                    if (n == 0)
                                        n = m;
                                    else
                                        n = 1 / m;
                                } else if (k == "/") {
                                    if (n == 0)
                                        n = m;
                                    else
                                        n = n / m;
                                }
                            }
                        }
                        k = b.getActionCommand();
                        ta.setText("");
                    } else if (b.getActionCommand().equals("=")) {
                        m = new Double(ta.getText()).doubleValue();
                        if (k == "+") {
                            ta.setText("");
                            ta.append(n + "+" + m);
                            ta.append(System.getProperty("line.separator"));
                            n = n + m;
                            ta.append("=" + n);
                        } else if (k == "-") {
                            ta.setText("");
                            ta.append(n + "-" + m);
                            ta.append(System.getProperty("line.separator"));
                            n = n - m;
                            ta.append("=" + n);
                        } else if (k == "*") {
                            ta.setText("");
                            ta.append(n + "*" + m);
                            ta.append(System.getProperty("line.separator"));
                            n = n * m;
                            ta.append("=" + n);
                        } else if (k == "%") {
                            ta.setText("");
                            ta.append("%" + m);
                            ta.append(System.getProperty("line.separator"));
                            m = m * 100;
                            ta.append("=" + m + "%");
                        } else if (k == "1/x") {
                            ta.setText("");
                            ta.append(1 + "/" + m);
                            ta.append(System.getProperty("line.separator"));
                            n = 1 / m;
                            ta.append("=" + n);
                        } else if (k == "/") {
                            ta.setText("");
                            ta.append(n + "/" + m);
                            ta.append(System.getProperty("line.separator"));
                            n = n / m;
                            ta.append("=" + n);
                        }
                        k = "=";
                        flag2 = true;
                    } else {
                        if (flag2) {
                            flag = true;
                            flag2 = false;
                            ta.setText("");
                            m = n = 0;
                        }
                        ta.append(b.getActionCommand());
                    }
                }
            }
        });
        this.add(b);
    }

    private void SetTextAreas() {
        ta = new TextArea("0", 8, 52, 3);
        ta.setBackground(Color.lightGray);
        ta.setSize(190, 50);
        ta.setFont(new Font("标楷体", Font.BOLD, 15));
        ta.setLocation(20, 60);
        this.add(ta);
        tb = new TextArea("  DESIGN BY Alec", 8, 52, 3);
        tb.setBackground(Color.pink);
        tb.setSize(190, 25);
        tb.setFont(new Font("标楷体", Font.BOLD, 16));
        tb.setForeground(Color.blue);
        tb.setLocation(20, 130);
        this.add(ta);
        this.add(tb);
    }

    @SuppressWarnings("deprecation")
    private void SetMainFram() {
        this.setLayout(null);
        this.setSize(220, 310);
        this.setVisible(true);
        this.setLocation(310, 340);
        this.setResizable(false);
        ta.setEditable(false);
        tb.setEditable(false);
        this.setCursor(Cursor.HAND_CURSOR);
        this.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });

    }
}

 仅供参考