java版计算器

[java]代码库

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.awt.*;
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.awt.Color;

/**
 * java版计算器
 */
public class Calculator extends JFrame {
	final int WIN_W = 250, WIN_H = 250;
	JPanel myPanel, panelSuper;

	public Calculator() {

		// 主面板
		panelSuper = new JPanel();
		panelSuper.setLayout(null);

		// 设置窗口位置
		double width = Toolkit.getDefaultToolkit().getScreenSize().width;
		double height = Toolkit.getDefaultToolkit().getScreenSize().height;
		this.setBounds((int) (width - WIN_W) / 2, (int) (height - WIN_H) / 2,
				WIN_W, WIN_H);

		// 窗口配置
		this.setTitle("java版计算器");
		this.validate();
		this.setResizable(false);
		this.setVisible(true);
		this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);

		// 添加计算器按钮面板
		myPanel = new MyPanel();
		this.add(myPanel, BorderLayout.CENTER);

	}

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

	/**
	 * 计算器按钮面板类
	 */
	class MyPanel extends JPanel implements ActionListener {
		JButton button1, button2, button3, button4, button5, button6, button7,
				button8, button9, button0, buttonJia, buttonJian, buttonCheng,
				buttonChu, buttonDeng, buttonDian, buttonC, buttonDel,
				buttonZF, buttonGH;
		JTextField jTextField; // 计算器显示屏
		char oper; // 操作符
		String key, allKey = "1234567890.±del", jjccKey = "+-*/";
		BigDecimal d1, d2;
		boolean first;

		public MyPanel() {

			// 设置布局
			this.setLayout(new FlowLayout(FlowLayout.LEFT, 4, 5));

			// 计算器显示屏
			jTextField = new JTextField(21);
			jTextField.setHorizontalAlignment(JTextField.RIGHT);
			jTextField.setEditable(false);
			jTextField.setBackground(new Color(255, 255, 255));
			jTextField.setText("0");
			this.add(jTextField);

			// 计算器按钮
			button1 = new JButton("1");
			button2 = new JButton("2");
			button3 = new JButton("3");
			button4 = new JButton("4");
			button5 = new JButton("5");
			button6 = new JButton("6");
			button7 = new JButton("7");
			button8 = new JButton("8");
			button9 = new JButton("9");
			button0 = new JButton("0");
			buttonJia = new JButton("+");
			buttonJian = new JButton("-");
			buttonCheng = new JButton("*");
			buttonChu = new JButton("/");
			buttonDeng = new JButton("=");
			buttonDian = new JButton(".");
			buttonDel = new JButton("del");
			buttonC = new JButton("c");
			buttonZF = new JButton("±");
			buttonGH = new JButton("√");
			button1.setPreferredSize(new Dimension(55, 30));
			button2.setPreferredSize(new Dimension(55, 30));
			button3.setPreferredSize(new Dimension(55, 30));
			button4.setPreferredSize(new Dimension(55, 30));
			button5.setPreferredSize(new Dimension(55, 30));
			button6.setPreferredSize(new Dimension(55, 30));
			button7.setPreferredSize(new Dimension(55, 30));
			button8.setPreferredSize(new Dimension(55, 30));
			button9.setPreferredSize(new Dimension(55, 30));
			button0.setPreferredSize(new Dimension(55, 30));
			buttonJia.setPreferredSize(new Dimension(55, 30));
			buttonJian.setPreferredSize(new Dimension(55, 30));
			buttonCheng.setPreferredSize(new Dimension(55, 30));
			buttonChu.setPreferredSize(new Dimension(55, 30));
			buttonDeng.setPreferredSize(new Dimension(55, 30));
			buttonDian.setPreferredSize(new Dimension(55, 30));
			buttonDel.setPreferredSize(new Dimension(55, 30));
			buttonC.setPreferredSize(new Dimension(55, 30));
			buttonZF.setPreferredSize(new Dimension(55, 30));
			buttonGH.setPreferredSize(new Dimension(55, 30));
			this.add(buttonDel);
			this.add(buttonC);
			this.add(buttonZF);
			this.add(buttonGH);
			this.add(button1);
			this.add(button2);
			this.add(button3);
			this.add(buttonJia);
			this.add(button4);
			this.add(button5);
			this.add(button6);
			this.add(buttonJian);
			this.add(button7);
			this.add(button8);
			this.add(button9);
			this.add(buttonCheng);
			this.add(button0);
			this.add(buttonDian);
			this.add(buttonDeng);
			this.add(buttonChu);
			buttonDel.addActionListener(this);
			buttonC.addActionListener(this);
			buttonZF.addActionListener(this);
			buttonGH.addActionListener(this);
			button1.addActionListener(this);
			button2.addActionListener(this);
			button3.addActionListener(this);
			button4.addActionListener(this);
			button5.addActionListener(this);
			button6.addActionListener(this);
			button7.addActionListener(this);
			button8.addActionListener(this);
			button9.addActionListener(this);
			button0.addActionListener(this);
			buttonJia.addActionListener(this);
			buttonJian.addActionListener(this);
			buttonCheng.addActionListener(this);
			buttonChu.addActionListener(this);
			buttonDeng.addActionListener(this);
			buttonDian.addActionListener(this);

			// 计算器初始化
			init();
		}

		/**
		 * 计算器初始化
		 */
		public void init() {
			d1 = new BigDecimal("0");
			d1 = new BigDecimal("0");
			key = "=";
			oper = '=';
			jTextField.setText("0");
			first = true; // 用于标记是否进行连续操作（例如按键顺序为“9*9====”，第一次等于first由true变为false，如果!first，按等号相当于用上一次的结果与第二个操作数相乘）
		}

		/**
		 * 按钮监听
		 */
		public void actionPerformed(ActionEvent e) {
			JButton b = (JButton) e.getSource();
			if (b == buttonDian) { // 按下.

				jTextField.setText(jTextField.getText() + ".");
				if (first) {
					d2 = d1 = getNum();
				} else {
					d2 = getNum();
				}
			} else if (b == buttonZF) {// 按下±
				BigDecimal d = getNum();
				d = new BigDecimal("0").subtract(d);
				setFormatNum(d);
				if (first) {
					d2 = d1 = getNum();
				} else {
					d2 = getNum();
				}
			} else if (b == buttonDel) {// 按下del
				if (jTextField.getText().length() == 1
						|| jTextField.getText().length() == 2
						&& jTextField.getText().startsWith("-")) {
					jTextField.setText("0");

				} else {
					String s = jTextField.getText();
					s = s.substring(0, s.length() - 1);
					if (s.endsWith("E+") || s.endsWith("E-"))
						s = s.substring(0, s.length() - 2);
					jTextField.setText(s);
					if (first) {
						d2 = d1 = getNum();
					} else {
						d2 = getNum();
					}
				}
			} else if (b == buttonC) {// 按下c
				init();
			} else if (b == buttonJia) {// 按下+
				BigDecimal s;
				if (!first && allKey.indexOf(key) >= 0) {
					if (oper == '-' || oper == '/') {
						s = operate(d1, oper, d2);
					} else {
						s = operate(d2, oper, d1);
					}
					setFormatNum(s);
				}// 如果不是第一次，且上一次操作是对数字进行操作
				else {

					first = false;
				}
				d2 = d1 = getNum();
				// System.out.print("111我执行啦\n");
				oper = '+';
			} else if (b == buttonJian) {// 按下-
				BigDecimal s;
				if (!first && allKey.indexOf(key) >= 0) {
					s = operate(d1, oper, d2);
					setFormatNum(s);
				}// 如果不是第一次，且上一次操作是对数字进行操作
				else {
					first = false;
				}
				d2 = d1 = getNum();
				oper = '-';
			} else if (b == buttonCheng) {// 按下*
				BigDecimal s;
				if (!first && allKey.indexOf(key) >= 0) {
					if (oper == '-' || oper == '/') {
						s = operate(d1, oper, d2);
					} else {
						s = operate(d2, oper, d1);
					}
					setFormatNum(s);
				}// 如果不是第一次，且上一次操作是对数字进行操作
				else {
					first = false;
				}
				d2 = d1 = getNum();
				oper = '*';
			} else if (b == buttonChu) {// 按下/
				BigDecimal s;
				if (!first && allKey.indexOf(key) >= 0) {
					s = operate(d1, oper, d2);
					setFormatNum(s);
				}// 如果不是第一次，且上一次操作是对数字进行操作
				else {
					first = false;
				}
				d2 = d1 = getNum();
				oper = '/';
			} else if (b == buttonGH) {// 按下平方根
				if (jTextField.getText().startsWith("-")) {
					init();
					return;
				}
				BigDecimal d = getNum();
				MathContext mc = new MathContext(10, RoundingMode.HALF_DOWN);
				d = new BigDecimal(Math.sqrt(d.doubleValue()), mc);
				setFormatNum(d);
				if (first) {
					d2 = d1 = getNum();
				} else {
					d2 = getNum();
				}
			} else if (b == buttonDeng) {// 按下=
				BigDecimal s = null;
				d2 = getNum();
				if (!key.equals("=")) {
					s = operate(d1, oper, d2);
				} else {
					s = operate(d2, oper, d1);
				}
				if (oper != '=' && !key.equals("=")) {// 上一次操作为 +-*/
					d1 = getNum();

				}
				setFormatNum(s);
				first = true;
			} else { // 按下其他按钮
				if (this.jTextField.getText().equals("0")
						|| allKey.indexOf(key) == -1) {
					this.jTextField.setText(b.getText());
				} else {
					this.jTextField.setText(jTextField.getText() + b.getText());
				}
				if (first) {
					d2 = d1 = getNum();
				} else {
					d2 = getNum();
				}// d2作被加数:d2+d1
			}
			key = b.getText();
		}

		/**
		 * 获取操作数
		 * 
		 * @return 操作数
		 */
		public BigDecimal getNum() {
			BigDecimal d = new BigDecimal(jTextField.getText());
			return d;
		}

		public void setFormatNum(BigDecimal dd) {
			MathContext mc = new MathContext(18, RoundingMode.HALF_DOWN);

			BigDecimal d = new BigDecimal(dd.toString(), mc);
			String num = d.toString();
			if (num.endsWith(".0"))
				num = num.replaceAll("\\.0", "");
			this.jTextField.setText(num);
		}

		/**
		 * 计算
		 * 
		 * @param a1
		 *            操作数1
		 * @param c
		 *            操作符
		 * @param a2
		 *            操作数2
		 * @return
		 */
		public BigDecimal operate(BigDecimal a1, char c, BigDecimal a2) {
			MathContext mc = new MathContext(10, RoundingMode.HALF_DOWN);
			switch (c) {
			case '+':
				return a1.add(a2);
			case '-':
				return a1.subtract(a2);
			case '*':
				return a1.multiply(a2);
			case '/':
				if (a2.compareTo(new BigDecimal("0")) == 0) {
					init();
					return new BigDecimal("0");
				}
				return a1.divide(a2, mc);
			default:
				return a2;
			}
		}
	}

}

[代码运行效果截图]