java - GUI计算器计算

Question

我目前正在使用的 GUI 计算器遇到一些问题。计算器进行编译并进行计算。要进行计算，您必须首先输入一个数字，选择一个函数(+、-、* 或/)，选择另一个数字，然后按等于。执行方程式后，必须先清除程序才能继续。我无法弄清楚如何制作它，以便程序在继续计算之前不需要按清除。我希望能够单击一个数字，单击+，单击一个数字，单击等于以获得答案，然后再次按+将另一个数字添加到方程中。任何有关此问题的帮助将不胜感激。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;


public class GUICalc extends JPanel implements ActionListener {

    private static final long serialVersionUID = 1L;

    private JButton[] numberButtons;
    private JButton[] upButtons;

    private JTextField field;
    private double num2, ans; 
    private int op;

    // 0 = gridx 1 gridy 2 gridwidth 3 gridheight
    private int[][] numConstraints = new int[][] {
            {0, 4, 1, 1},
            {0, 1, 1, 1},
            {1, 1, 1, 1},
            {2, 1, 1, 1},
            {0, 2, 1, 1},
            {1, 2, 1, 1},
            {2, 2, 1, 1},
            {0, 3, 1, 1},
            {1, 3, 1, 1},
            {2, 3, 1, 1},
    };

    private int[][] upConstraints = new int[][] {
            {1, 4, 1, 1},
            {3, 4, 1, 1},
            {3, 3, 1, 1},
            {3, 2, 1, 1},
            {3, 1, 1, 1},
            {0, 5, 4, 1},
            {2, 4, 1, 1},
    };

    public GUICalc() {
        setPreferredSize(new Dimension(666, 666)); //width & heigth

        GridBagLayout layout; // used to be private
        GridBagConstraints gbc; // used to be private

        layout = new GridBagLayout();
        layout.columnWidths = new int[] {60, 60, 60, 60};
        layout.rowHeights = new int[] {60, 60, 60, 60, 60, 60};
        setLayout(layout);

        gbc = new GridBagConstraints();

            numberButtons = new JButton[10];

            numberButtons[0] = new JButton("0");
            numberButtons[1] = new JButton("1");
            numberButtons[2] = new JButton("2");
            numberButtons[3] = new JButton("3");
            numberButtons[4] = new JButton("4");
            numberButtons[5] = new JButton("5");
            numberButtons[6] = new JButton("6");
            numberButtons[7] = new JButton("7");
            numberButtons[8] = new JButton("8");
            numberButtons[9] = new JButton("9");

            for(int i = 0; i < numberButtons.length; i++){
            gbc.gridx = numConstraints[i][0];
            gbc.gridy = numConstraints[i][1];
            gbc.gridwidth = numConstraints[i][2];
            gbc.gridheight = numConstraints[1][3];
            gbc.fill = GridBagConstraints.BOTH;
            gbc.insets = new Insets(2, 2, 2, 2); 
            numberButtons[i].addActionListener(this);
            add(numberButtons[i], gbc);
            }

        upButtons = new JButton[7];

        upButtons[0] = new JButton(".");
        upButtons[1] = new JButton("/");
        upButtons[2] = new JButton("*");
        upButtons[3] = new JButton("-");
        upButtons[4] = new JButton("+");
        upButtons[5] = new JButton("=");
        upButtons[6] = new JButton("C");

        for(int i = 0; i < upButtons.length; i++){
            gbc.gridx = upConstraints[i][0];
            gbc.gridy = upConstraints[i][1];
            gbc.gridwidth = upConstraints[i][2];
            gbc.gridheight = upConstraints[1][3];
            gbc.insets = new Insets(2, 2, 2, 2);
            upButtons[i].addActionListener(this);
            add(upButtons[i], gbc); 


        }

        field = new JTextField();
        field.setBorder(BorderFactory.createLineBorder(Color.BLACK));
        field.setEditable(false);
        field.setFont(new Font("Arial",Font.PLAIN, 24));
        field.setText(null);

        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.gridwidth = 4;
        gbc.gridheight = 1;

        add(field, gbc);

    }


    public static void main(String [] args){
        JFrame frame = new JFrame("Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setResizable(false);
        frame.setLayout(new BorderLayout());
        frame.add(new GUICalc(), BorderLayout.CENTER);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);     

    }


    @Override
    public void actionPerformed(ActionEvent e) {

            if(e.getSource() == numberButtons[0]){
            field.setText(field.getText() + 0);
            }
            if(e.getSource() == numberButtons[1]){
            field.setText(field.getText() + 1);
            }
            if(e.getSource() == numberButtons[2]){
            field.setText(field.getText() + 2);
            }
            if(e.getSource() == numberButtons[3]){
            field.setText(field.getText() + 3);
            }
            if(e.getSource() == numberButtons[4]){
            field.setText(field.getText() + 4);
            }
            if(e.getSource() == numberButtons[5]){
            field.setText(field.getText() + 5);
            }
            if(e.getSource() == numberButtons[6]){
            field.setText(field.getText() + 6);
            }
            if(e.getSource() == numberButtons[7]){
            field.setText(field.getText() + 7);
            }
            if(e.getSource() == numberButtons[8]){
            field.setText(field.getText() + 8);
            }
            if(e.getSource() == numberButtons[9]){
            field.setText(field.getText() + 9);
            }

        if(e.getSource() == upButtons[0] && !field.getText().contains(".")) {
            field.setText(field.getText() + ".");
        }

        if(e.getSource() == upButtons[1]) {
            ans = Integer.parseInt(field.getText());
            op = 4;
            field.setText("");
        }

        if(e.getSource() == upButtons[2]) {
            ans = Integer.parseInt(field.getText());
            op = 3;
            field.setText("");
        }
        if(e.getSource() == upButtons[3]) {
            ans = Integer.parseInt(field.getText());
            op = 2;
            field.setText("");
        }
        if(e.getSource() == upButtons[4]) {
            ans = Integer.parseInt(field.getText());
            op = 1;
            field.setText("");
        }
        if(e.getSource() == upButtons[5]) {
            num2 = Integer.parseInt(field.getText());

            if(op == 1){
                ans = ans + num2;
            } else if(op == 2){
                ans = ans - num2;

            } else if(op == 3){
                ans = ans * num2;
            } else if(op == 4){
                ans = ans / num2;
            } 

            op = 0;
            field.setText("" + ans);
        }

        if(e.getSource() == upButtons[6]) {
            ans = 0.0;
            field.setText("");
        }
    }


}

Answer 1

您的程序的问题在于您对 double 进行计算，但将文本解析为整数。将 Integer.parseInt 替换为 Double.parseDouble，它将如您所愿。