/*部分使用插件做界面*/

import java.awt.EventQueue;

import javax.swing.JButton;

import javax.swing.JFrame;

import java.awt.BorderLayout;

import javax.swing.JTextField;

import javax.swing.SwingConstants;

import java.awt.Font;

import javax.swing.JPanel;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.border.EmptyBorder;

/**

 * @author 李祖林

 * @Time 2017-6-22

 */

public class Calcultor implements ActionListener {

    int i;

    int status = 0; // 保存运算符：0为空，1为加，2为减，3为乘，4为除

    double sum1 = 0, sum2 = 0; // sum1为第一个数，也用于保存连续运算中的结果,sum2为第二个数

    boolean key = false; // 判断是否有运算符

    private JFrame frame;

    JButton[] bN = new JButton[10]; // bN为数字按钮，0-9分别表示0-9个数字

    JButton[] bC = new JButton[6]; // bC为运算符按钮

    private JTextField textField;

    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {

            public void run() {

                try {

                    Calcultor window = new Calcultor();

                    window.frame.setVisible(true);

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

        });

    }

    public Calcultor() {

        frame = new JFrame();

        frame.setBounds(100, 100, 510, 310);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.getContentPane().setLayout(new BorderLayout(0, 0));

        textField = new JTextField();

        textField.setFont(new Font("宋体", Font.BOLD, 18));

        textField.setHorizontalAlignment(SwingConstants.RIGHT);

        frame.getContentPane().add(textField, BorderLayout.NORTH);

        textField.setColumns(10);

        JPanel panel = new JPanel();

        panel.setBorder(new EmptyBorder(20, 20, 20, 20)); // 设置panel的空白的上下左右间距为20

        frame.getContentPane().add(panel, BorderLayout.CENTER);

        panel.setLayout(new GridLayout(4, 4, 20, 20));

        for (i = 0; i <= 9; i++) {

            bN[i] = new JButton(String.valueOf(i)); // String.valueOf(i)可以将其他类型数据转化为字符串

            bN[i].addActionListener(this);

        }

        bC[0] = new JButton("C"); // bC[0]表示清空

        bC[1] = new JButton("+"); // bC[1]表示加

        bC[2] = new JButton("-"); // bC[2]表示减

        bC[3] = new JButton("*"); // bC[3]表示乘

        bC[4] = new JButton("/"); // bC[4]表示除

        bC[5] = new JButton("="); // bC[5]表示等于

        for (i = 0; i <= 5; i++) {

            bC[i].addActionListener(this);

        }

        panel.add(bN[9]);

        panel.add(bN[8]);

        panel.add(bN[7]);

        panel.add(bC[0]);

        panel.add(bN[6]);

        panel.add(bN[5]);

        panel.add(bN[4]);

        panel.add(bC[1]);

        panel.add(bN[3]);

        panel.add(bN[2]);

        panel.add(bN[1]);

        panel.add(bC[2]);

        panel.add(bN[0]);

        panel.add(bC[3]);

        panel.add(bC[4]);

        panel.add(bC[5]);

    }

    public void actionPerformed(ActionEvent e) {

        if (e.getSource() == bC[0]) {

            sum1 = 0;

            sum2 = 0;

            status = 0;

            key = false;

            textField.setText("");

        }

        if (key == false) { // 未按下运算符

            for (i = 0; i <= 9; i++) {

                if (e.getSource() == bN[i]) { // 如果为数字按钮

                    sum1 = sum1 * 10 + i;

                    textField.setText(String.valueOf(sum1));

                }

            }

            for (i = 1; i <= 4; i++) { // 如果为控制按钮

                if (e.getSource() == bC[i]) {

                    status = i; // 保存运算符的状态

                    key = true; // 标记已按下运算符

                }

            }

        } else {

            boolean tmp = false;

            for (i = 0; i <= 9; i++) {

                if (e.getSource() == bN[i]) {

                    tmp = true;

                    sum2 = sum2 * 10 + i;

                    textField.setText(String.valueOf(sum2));

                }

            }

            if (tmp == false) {

                switch (status) {

                case 1:

                    sum1 = sum1 + sum2;

                    break;

                case 2:

                    sum1 = sum1 - sum2;

                    break;

                case 3:

                    sum1 = sum1 * sum2;

                    break;

                case 4:

                    sum1 = sum1 / sum2;

                    break;

                }

                for (i = 1; i <= 4; i++) {

                    if (e.getSource() == bC[i]) {

                        status = i;

                        sum2 = 0;

                    }

                }

                if (e.getSource() == bC[5]) {

                    status = 0;

                    textField.setText(String.valueOf(sum1));

                    sum1 = 0;

                    sum2 = 0;

                    key = false;

                }

            }

        }

    }

}