如何在 AWT/SWING 中从同一文本字段输入两位数字

Question

I have created a Simple calculator in which I take inputs of two operands in two different textfields, and it is working good. But I need to take two inputs from same textfield. What changes should I make?

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

class Calculation_ActionEvent extends JFrame implements ActionListener
{
    JFrame f;
    JLabel l;
    JTextField tf1, tf2, tf3;
    JButton b1, b2, b3, b4 ,b5, b6;
    Calculation_ActionEvent(String s)
    {
        f = new JFrame("Calculation");
        f.setLayout(null);
        l = new JLabel("Enter two numbers : ");
        tf1 = new JTextField();
        tf2 = new JTextField();
        tf3 = new JTextField();
        b1 = new JButton("+");
        b2 = new JButton("-");
        b3 = new JButton("*");
        b4 = new JButton("/");
        b5 = new JButton("equals");
        b6 = new JButton("C");
        f.add(l);
        f.add(tf1);
        f.add(tf2);
        f.add(tf3);
        f.add(b1);
        f.add(b2);
        f.add(b3);
        f.add(b4);
        f.add(b5);
        f.add(b6);
        tf1.setBounds(180,100,50,30);
        tf2.setBounds(320,100,50,30);
        tf3.setBounds(250,420,50,30);
        b1.setBounds(250,180,50,30);
        b2.setBounds(350,260,50,30);
        b3.setBounds(150,260,50,30);
        b4.setBounds(250,340,50,30);
        b5.setBounds(230,260,90,30);
        b6.setBounds(250,100,50,30);
        b1.addActionListener(this);
        b2.addActionListener(this);
        b3.addActionListener(this);
        b4.addActionListener(this);
      //b5.addActionListener(this);
        b6.addActionListener(this);
        f.setSize(550,550);
        f.setVisible(true);
    }

    public void actionPerformed(ActionEvent e)
    {
        int num1= Integer.parseInt(tf1.getText());
        int num2= Integer.parseInt(tf2.getText());
        String s1 = e.getActionCommand();
        if(s1.equals("C"))
        {
            tf1.setText("0");
            tf2.setText("0");
            tf3.setText("0");
        }
        else
        {
         if(s1=="+")
        {
            tf3.setText(String.valueOf(num1+num2)); 
        }
        if(s1=="-")
        {
            tf3.setText(String.valueOf(num1-num2)); 
        }
        if(s1=="*")
        {
            tf3.setText(String.valueOf(num1*num2)); 
        }
        if(s1=="/")
        {
            tf3.setText(String.valueOf(num1/num2)); 
        }
        }
 }

    public static void main(String... s)
    {
        new Calculation_ActionEvent("Calculation");
    }
 }

Answer 1

Just get the value from the two textbox and perform all the calculation addition,multiplication,subtraction,divide and store in different variable and the set that variable in textbox you cant directly perform the action in textbox.ex below

String val1=textbox1.gettext();
String val2=textbox2.gettext();
int addition=Integer.ParseInt(val1)+Integer.ParseInt(val2);
textbox3.settext(addition.toString());

Answer 2

Would this be something like what you're looking for? I did a quick version for you.

Simply put, I store the last operator ( + , - , * , / ) in a String variable ( lastAction ), the total as an int . When "equals" is pressed, I work out the total and reset the total variable and lastAction . When an operator is pressed, I change the total but keep the last value in a variable.

package cf.pgmann.calc;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

class Calculation_ActionEvent extends JFrame implements ActionListener {
    JFrame f;
    JLabel l;
    JTextField tf1, tf3;
    JButton b1, b2, b3, b4, b5, b6;

    Calculation_ActionEvent(String s) {
        f = new JFrame(s);
        f.setLayout(null);
        l = new JLabel("Enter two numbers : ");
        tf1 = new JTextField();
        // tf2 = new JTextField();
        tf3 = new JTextField();
        b1 = new JButton("+");
        b2 = new JButton("-");
        b3 = new JButton("*");
        b4 = new JButton("/");
        b5 = new JButton("equals");
        b6 = new JButton("C");
        f.add(l);
        f.add(tf1);
        f.add(tf3);
        f.add(b1);
        f.add(b2);
        f.add(b3);
        f.add(b4);
        f.add(b5);
        f.add(b6);
        tf1.setBounds(160, 100, 250, 30);
        // tf2.setBounds(320,100,50,30);
        tf3.setBounds(250, 420, 50, 30);
        b1.setBounds(250, 180, 50, 30);
        b2.setBounds(350, 260, 50, 30);
        b3.setBounds(150, 260, 50, 30);
        b4.setBounds(250, 340, 50, 30);
        b5.setBounds(230, 260, 90, 30);
        b6.setBounds(420, 100, 50, 30);
        b1.addActionListener(this);
        b2.addActionListener(this);
        b3.addActionListener(this);
        b4.addActionListener(this);
        b5.addActionListener(this);
        b6.addActionListener(this);
        f.setSize(550, 550);
        f.setVisible(true);
    }

    int total = 0;
    String lastAction = "";

    public void actionPerformed(ActionEvent e) {
        int num = 0;
        try {
            num = Integer.parseInt(tf1.getText());
        } catch(NumberFormatException ex) {}
        String s1 = e.getActionCommand();
        if (s1.equals("C")) {
            tf1.setText("");
            tf3.setText("0");
            tf1.requestFocus();
            total = 0;
        } else if (s1.equals("equals")) {
            tf3.setText(String.valueOf(calc(total, lastAction, num)));
            tf1.setText("");
            tf1.requestFocus();
            total = 0;
        } else {
            total = total==0 ? num : calc(total, lastAction, num);
            tf3.setText(String.valueOf(total));
            tf1.setText("");
            tf1.requestFocus();
            lastAction = s1;
        }
    }

    private int calc(int num1, String action, int num2) {
        switch (action) {
        case "+":
            return num1 + num2;
        case "-":
            return num1 - num2;
        case "*":
            return num1 * num2;
        case "/":
            return num1 / num2;
        default:
            return num1;
        }
    }

    public static void main(String... s) {
        new Calculation_ActionEvent("Calculator");
    }
}