因此，在我的基本 Java 计算器代码中，该代码似乎只在第一次运行。我找不到问题的根源，但可能与清晰的功能有关。我真的是一个 Java 菜鸟，非常感谢更有经验的编码人员提供的任何帮助!
package Calculator;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class Calculator extends JFrame implements ActionListener {
/**
*
*/
private static final long serialVersionUID = 1L;
JButton num1, num2, num3, num4, num5, num6, num7, num8, num9, num0, add, sub, div, times, equals, exit, point, reset;
JTextField txtfld;
static String s = "", func = "";
int flag = 0;
static double total1;
double first, second;
Double toDouble(String a) {
double i = Double.parseDouble(a);
return i;
}
void total(double first, double second, String func) {
String total;
if ("+".equals(func)) {
total1 = first + second;
// System.out.println(first+"\n"+second+"\n"+sum);
total = Double.toString(total1);
txtfld.setText(total);
} else if ("-".equals(func)) {
total1 = first - second;
total = Double.toString(total1);
txtfld.setText(total);
} else if ("*".equals(func)) {
total1 = first * second;
total = Double.toString(total1);
txtfld.setText(total);
} else if ("/".equals(func)) {
total1 = first / second;
total = Double.toString(total1);
txtfld.setText(total);
}
}
public Calculator() {
Container content = getContentPane();
content.setLayout(new FlowLayout());
JLabel jl = new JLabel(" Java GUI Calculator ");
txtfld = new JTextField(15);
num1 = new JButton(" 1 ");
num2 = new JButton(" 2 ");
num3 = new JButton(" 3 ");
num4 = new JButton(" 4 ");
num5 = new JButton(" 5 ");
num6 = new JButton(" 6 ");
num7 = new JButton(" 7 ");
num8 = new JButton(" 8 ");
num9 = new JButton(" 9 ");
num0 = new JButton(" 0 ");
add = new JButton(" + ");
sub = new JButton(" - ");
div = new JButton(" / ");
times = new JButton(" * ");
equals = new JButton(" = ");
exit = new JButton(" Exit ");
point = new JButton(" . ");
reset = new JButton("C");
reset.setBackground(Color.RED);
num1.addActionListener(this);
num2.addActionListener(this);
num3.addActionListener(this);
num4.addActionListener(this);
num5.addActionListener(this);
num6.addActionListener(this);
num7.addActionListener(this);
num8.addActionListener(this);
num9.addActionListener(this);
num0.addActionListener(this);
add.addActionListener(this);
sub.addActionListener(this);
times.addActionListener(this);
div.addActionListener(this);
equals.addActionListener(this);
exit.addActionListener(this);
point.addActionListener(this);
reset.addActionListener(this);
content.add(jl);
content.add(txtfld);
content.add(num1);
content.add(num2);
content.add(num3);
content.add(add);
content.add(num4);
content.add(num5);
content.add(num6);
content.add(sub);
content.add(num7);
content.add(num8);
content.add(num9);
content.add(div);
content.add(num0);
content.add(point);
content.add(times);
content.add(equals);
content.add(reset);
content.add(exit);
}
public static void main(String arg[]) {
Calculator jf = new Calculator();
jf.setSize(230, 250);
jf.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
Object o = e.getSource();
if (o == num1) {
txtfld.setText(s.concat("1"));
s = txtfld.getText();
} else if (o == num2) {
txtfld.setText(s.concat("2"));
s = txtfld.getText();
} else if (o == num3) {
txtfld.setText(s.concat("3"));
s = txtfld.getText();
} else if (o == num4) {
txtfld.setText(s.concat("4"));
s = txtfld.getText();
} else if (o == num5) {
txtfld.setText(s.concat("5"));
s = txtfld.getText();
} else if (o == num6) {
txtfld.setText(s.concat("6"));
s = txtfld.getText();
} else if (o == num7) {
txtfld.setText(s.concat("7"));
s = txtfld.getText();
} else if (o == num8) {
txtfld.setText(s.concat("8"));
s = txtfld.getText();
} else if (o == num9) {
txtfld.setText(s.concat("9"));
s = txtfld.getText();
} else if (o == num0) {
txtfld.setText(s.concat("0"));
s = txtfld.getText();
} else if (o == add) {
txtfld.setText("");
first = toDouble(s);
System.out.println(first);
s = "";
func = "+";
} else if (o == sub) {
txtfld.setText("");
first = toDouble(s);
s = "";
func = "-";
} else if (o == times) {
txtfld.setText("");
first = toDouble(s);
s = "";
func = "*";
} else if (o == div) {
txtfld.setText("");
first = toDouble(s);
s = "";
func = "/";
} else if (o == equals) {
if (flag == 0) {
second = toDouble(s);
total(first, second, func);
flag = 1;
} else if (flag == 1) {
second = toDouble(s);
total(total1, second, func);
}
System.out.println(first);
} else if (o == exit) {
System.exit(0);
} else if (o == point) {
txtfld.setText(s.concat("."));
s = txtfld.getText();
}
if (o == reset) {
total1 = 0;
txtfld.setText("");
s = txtfld.getText();
}
}
}
最佳答案
试试这个，效果很完美
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package com.java.util.test;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.HashMap;
import javax.swing.JFrame;
/**
*
* @author shreyansh.jogi
*/
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class JavaApplication2 extends JFrame implements ActionListener {
/**
*
*/
private static final long serialVersionUID = 1L;
JButton num1, num2, num3, num4, num5, num6, num7, num8, num9, num0, add, sub, div, mult, equalto, exit, point, reset;
JTextField txtfld;
String s = "", ope = "";
int flag = 0;
double total1;
double first, second;
Double toDouble(String a) {
double i = Double.parseDouble(a);
return i;
}
void total(double first, double second, String ope) {
String total;
if (ope.equalsIgnoreCase("+")) {
total1 = first + second;
// System.out.println(first+"\n"+second+"\n"+sum);
total = Double.toString(total1);
txtfld.setText(total);
} else if (ope.equalsIgnoreCase("-")) {
total1 = first - second;
total = Double.toString(total1);
txtfld.setText(total);
} else if (ope.equalsIgnoreCase("*")) {
total1 = first * second;
total = Double.toString(total1);
txtfld.setText(total);
} else if (ope.equalsIgnoreCase("/")) {
total1 = first / second;
total = Double.toString(total1);
txtfld.setText(total);
}
clearfields();
}
public JavaApplication2() {
Container content = getContentPane();
content.setLayout(new FlowLayout());
JLabel jl = new JLabel(" Calculator ");
txtfld = new JTextField(15);
num1 = new JButton(" 1 ");
num2 = new JButton(" 2 ");
num3 = new JButton(" 3 ");
num4 = new JButton(" 4 ");
num5 = new JButton(" 5 ");
num6 = new JButton(" 6 ");
num7 = new JButton(" 7 ");
num8 = new JButton(" 8 ");
num9 = new JButton(" 9 ");
num0 = new JButton(" 0 ");
add = new JButton(" + ");
sub = new JButton(" - ");
div = new JButton(" / ");
mult = new JButton(" * ");
equalto = new JButton(" = ");
exit = new JButton(" Exit ");
point = new JButton(" . ");
reset = new JButton("C");
reset.setBackground(Color.RED);
num1.addActionListener(this);
num2.addActionListener(this);
num3.addActionListener(this);
num4.addActionListener(this);
num5.addActionListener(this);
num6.addActionListener(this);
num7.addActionListener(this);
num8.addActionListener(this);
num9.addActionListener(this);
num0.addActionListener(this);
add.addActionListener(this);
sub.addActionListener(this);
mult.addActionListener(this);
div.addActionListener(this);
equalto.addActionListener(this);
exit.addActionListener(this);
point.addActionListener(this);
reset.addActionListener(this);
content.add(jl);
content.add(txtfld);
content.add(num1);
content.add(num2);
content.add(num3);
content.add(add);
content.add(num4);
content.add(num5);
content.add(num6);
content.add(sub);
content.add(num7);
content.add(num8);
content.add(num9);
content.add(div);
content.add(num0);
content.add(point);
content.add(mult);
content.add(equalto);
content.add(reset);
content.add(exit);
}
public static void main(String arg[]) {
JavaApplication2 jf = new JavaApplication2();
jf.setSize(230, 250);
jf.setVisible(true);
}
public void actionPerformed(ActionEvent e) {
Object o = e.getSource();
if (o == num1) {
txtfld.setText(s.concat("1"));
s = txtfld.getText();
} else if (o == num2) {
txtfld.setText(s.concat("2"));
s = txtfld.getText();
} else if (o == num3) {
txtfld.setText(s.concat("3"));
s = txtfld.getText();
} else if (o == num4) {
txtfld.setText(s.concat("4"));
s = txtfld.getText();
} else if (o == num5) {
txtfld.setText(s.concat("5"));
s = txtfld.getText();
} else if (o == num6) {
txtfld.setText(s.concat("6"));
s = txtfld.getText();
} else if (o == num7) {
txtfld.setText(s.concat("7"));
s = txtfld.getText();
} else if (o == num8) {
txtfld.setText(s.concat("8"));
s = txtfld.getText();
} else if (o == num9) {
txtfld.setText(s.concat("9"));
s = txtfld.getText();
} else if (o == num0) {
txtfld.setText(s.concat("0"));
s = txtfld.getText();
} else if (o == add) {
txtfld.setText("");
first = toDouble(s);
System.out.println(first);
s = "";
ope = "+";
} else if (o == sub) {
txtfld.setText("");
first = toDouble(s);
s = "";
ope = "-";
} else if (o == mult) {
txtfld.setText("");
first = toDouble(s);
s = "";
ope = "*";
} else if (o == div) {
txtfld.setText("");
first = toDouble(s);
s = "";
ope = "/";
} else if (o == equalto) {
if (flag == 0) {
second = toDouble(s);
total(first, second, ope);
flag = 1;
} else if (flag == 1) {
second = toDouble(s);
total(first, second, ope);
}
System.out.println(first);
} else if (o == exit) {
System.exit(0);
} else if (o == point) {
txtfld.setText(s.concat("."));
s = txtfld.getText();
}
if (o == reset) {
txtfld.setText("");
s = txtfld.getText();
total1 = 0;
}
}
private void clearfields() {
first=0;
second=0;
ope="";
flag = 0;
total1 = 0;
s="";
}
}
//System.out.println(stem[0]);
关于java - 计算器仅在第一次运行，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17342013/