我正在尝试用Java编写科学计算器。但是，我在尝试实际计算程序时遇到了困难。您可以在下面的代码中看到，我已经设法让GUI使用GUI上的数字打印。我还在“+”按钮中添加了功能，以便首先测试它以查看程序是否有效。
public class Gui extends JFrame {
private static JButton [] button = new JButton[36];
private static TextField tf;
private JPanel panel;
private JPanel panel1;
public Gui(){
super("Scientific Calculator");
panel = new JPanel();
panel1 = new JPanel(new GridLayout(0,4));
tf = new TextField(20);
tf.setEditable(false);
panel.add(tf);
button[0]=new JButton("Rad/Deg");
button[1]=new JButton("x!");
button[2]=new JButton("sqrt");
button[3]=new JButton("sin");
button[4]=new JButton("cos");
button[5]=new JButton("tan");
button[6]=new JButton("ln");
button[7]=new JButton("log");
button[8]=new JButton("1/x");
button[9]=new JButton("e^x");
button[10]=new JButton("x^2");
button[11]=new JButton("y^x");
button[12]=new JButton("|x|");
button[13]=new JButton("pi");
button[14]=new JButton("e");
button[15]=new JButton("C");
button[16]=new JButton("(");
button[17]=new JButton(")");
button[18]=new JButton("%");
button[19]=new JButton("/");
button[20]=new JButton("7");
button[21]=new JButton("8");
button[22]=new JButton("9");
button[23]=new JButton("*");
button[24]=new JButton("4");
button[25]=new JButton("5");
button[26]=new JButton("6");
button[27]=new JButton("-");
button[28]=new JButton("1");
button[29]=new JButton("2");
button[30]=new JButton("3");
button[31]=new JButton("+");
button[32]=new JButton(".");
button[33]=new JButton("0");
button[34] =new JButton("+/-");
button[35] =new JButton("=");
for(int i = 0; i<button.length;i++){
panel1.add(button[i]);
}
panel.add(panel1);
add(panel);
HandlerClass handler = new HandlerClass();
for(int i = 0; i<button.length;i++){
button[i].addActionListener(handler);
}
}
private class HandlerClass implements ActionListener{
@Override
public void actionPerformed(ActionEvent e) {
double num1 = 0,num2;
String alreadyDisplayed = tf.getText();
String toDisplay = "";
if(e.getSource()==button[33]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[33].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[28]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[28].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[29]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[29].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[30]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[30].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[24]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[24].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[25]){
alreadyDisplayed = tf.getText();
toDisplay = (button[25].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[26]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[26].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[20]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[20].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[21]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[21].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[22]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[22].getText());
tf.setText(toDisplay);
}
if(e.getSource()==button[31]){
alreadyDisplayed = tf.getText();
toDisplay = alreadyDisplayed + (button[31].getText());
tf.setText(toDisplay);
}
然而我的问题是事后要做什么。我想要做的是有一个try和catch块来查看第一个输入是否是一个数字，然后将其转换为double，然后将其存储在一个数组中，以便我可以使用运算符函数然后继续添加数字直到用户想要停止并执行计算。我对此代码的尝试如下，但这是错误的。有人可以建议我做错了吗？感谢
try{
num1 = Double.parseDouble(toDisplay);
}
catch(NumberFormatException e1){
System.out.println("You have not entered a number");
}
double[] arr = new double[10];
for(int i=0; i<arr.length;i++){
arr[i]=num1;
String test = String.valueOf(arr[i]);
tf.setText(test);
}
编辑我为另一个用户推荐的简单计算器编写了新代码，它适用于两个输入。但是，当我尝试实现多个输入时，我仍然会遇到错误。下面是两个输入计算器的工作代码。
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class CalcGui extends JFrame {
private JButton buttonZero;
private JButton buttonOne;
private JButton buttonTwo;
private JButton buttonThree;
private JButton buttonFour;
private JButton buttonFive;
private JButton buttonSix;
private JButton buttonSeven;
private JButton buttonEight;
private JButton buttonNine;
private JButton opButtonPlus;
private JButton opButtonMinus;
private JButton opButtonDivide;
private JButton opButtonMultiply;
private JButton opButtonEquals;
private JButton opButtonClear;
private TextField tf;
private JPanel numButtonPanel;
private JPanel opButtonPanel;
private JPanel basePanel;
public CalcGui(){
super("Scientific Calculator");
basePanel = new JPanel();
numButtonPanel = new JPanel(new GridLayout(0,4));
opButtonPanel = new JPanel(new GridLayout(0,1));
tf = new TextField(20);
tf.setEditable(false);
basePanel.add(tf);
buttonZero = new JButton("0");
numButtonPanel.add(buttonZero);
buttonOne = new JButton("1");
numButtonPanel.add(buttonOne);
buttonTwo = new JButton("2");
numButtonPanel.add(buttonTwo);
buttonThree = new JButton("3");
numButtonPanel.add(buttonThree);
buttonFour = new JButton("4");
numButtonPanel.add(buttonFour);
buttonFive = new JButton("5");
numButtonPanel.add(buttonFive);
buttonSix = new JButton("6");
numButtonPanel.add(buttonSix);
buttonSeven = new JButton("7");
numButtonPanel.add(buttonSeven);
buttonEight = new JButton("8");
numButtonPanel.add(buttonEight);
buttonNine = new JButton("9");
numButtonPanel.add(buttonNine);
basePanel.add(numButtonPanel);
opButtonPlus = new JButton("+");
opButtonMinus = new JButton("-");
opButtonDivide = new JButton("/");
opButtonMultiply = new JButton("*");
opButtonEquals = new JButton("=");
opButtonClear = new JButton("C");
opButtonPanel.add(opButtonPlus);
opButtonPanel.add(opButtonMinus);
opButtonPanel.add(opButtonDivide);
opButtonPanel.add(opButtonMultiply);
opButtonPanel.add(opButtonEquals);
opButtonPanel.add(opButtonClear);
basePanel.add(opButtonPanel);
add(basePanel);
HandlerClass handler = new HandlerClass();
buttonZero.addActionListener(handler);
buttonOne.addActionListener(handler);
buttonTwo.addActionListener(handler);
buttonThree.addActionListener(handler);
buttonFour.addActionListener(handler);
buttonFive.addActionListener(handler);
buttonSix.addActionListener(handler);
buttonSeven.addActionListener(handler);
buttonEight.addActionListener(handler);
buttonNine.addActionListener(handler);
opButtonPlus.addActionListener(handler);
opButtonMinus.addActionListener(handler);
opButtonDivide.addActionListener(handler);
opButtonMultiply.addActionListener(handler);
opButtonEquals.addActionListener(handler);
opButtonClear.addActionListener(handler);
}
private class HandlerClass implements ActionListener{
public void actionPerformed(ActionEvent e){
String alreadyDisplayed = tf.getText();
if(e.getSource()==buttonZero){
String buttonZeroText = alreadyDisplayed + buttonZero.getText();
tf.setText(buttonZeroText);
}else if(e.getSource()==buttonOne){
String buttonOneText = alreadyDisplayed + buttonOne.getText();
tf.setText(buttonOneText);
}else if(e.getSource()==buttonTwo){
String buttonTwoText = alreadyDisplayed + buttonTwo.getText();
tf.setText(buttonTwoText);
}else if(e.getSource()==buttonThree){
String buttonThreeText = alreadyDisplayed + buttonThree.getText();
tf.setText(buttonThreeText);
}else if(e.getSource()==buttonFour){
String buttonFourText = alreadyDisplayed + buttonFour.getText();
tf.setText(buttonFourText);
}else if(e.getSource()==buttonFive){
String buttonFiveText = alreadyDisplayed + buttonFive.getText();
tf.setText(buttonFiveText);
}else if(e.getSource()==buttonSix){
String buttonSixText = alreadyDisplayed + buttonSix.getText();
tf.setText(buttonSixText);
}else if(e.getSource()==buttonSeven){
String buttonSevenText = alreadyDisplayed + buttonSeven.getText();
tf.setText(buttonSevenText);
}else if(e.getSource()==buttonEight){
String buttonEightText = alreadyDisplayed + buttonEight.getText();
tf.setText(buttonEightText);
}else if(e.getSource()==buttonNine){
String buttonNineText = alreadyDisplayed + buttonNine.getText();
tf.setText(buttonNineText);
}else if(e.getSource()==opButtonPlus){
String opButtonPlusText = alreadyDisplayed + opButtonPlus.getText();
tf.setText(opButtonPlusText);
}else if(e.getSource()==opButtonEquals){
String opButtonEqualsText = alreadyDisplayed + opButtonEquals.getText();
tf.setText(opButtonEqualsText);
}else if(e.getSource()==opButtonMinus){
String opButtonMinusText = alreadyDisplayed + opButtonMinus.getText();
tf.setText(opButtonMinusText);
}else if(e.getSource()==opButtonMultiply){
String opButtonMultiplyText = alreadyDisplayed + opButtonMultiply.getText();
tf.setText(opButtonMultiplyText);
}else if(e.getSource()==opButtonDivide){
String opButtonDivideText = alreadyDisplayed + opButtonDivide.getText();
tf.setText(opButtonDivideText);
}else if(e.getSource()==opButtonClear){
String opButtonClearText = "";
tf.setText(opButtonClearText);
}
double result;
for(int i=0; i<alreadyDisplayed.length();i++){
if(e.getSource()==opButtonEquals){
if(alreadyDisplayed.charAt(i)=='+'){
result = Double.parseDouble(alreadyDisplayed.substring(0,i)) + Double.parseDouble(alreadyDisplayed.substring(i+1,alreadyDisplayed.length()));
tf.setText(alreadyDisplayed + "=" + result);
}else if(alreadyDisplayed.charAt(i)=='-'){
result = Double.parseDouble(alreadyDisplayed.substring(0,i)) - Double.parseDouble(alreadyDisplayed.substring(i+1,alreadyDisplayed.length()));
tf.setText(alreadyDisplayed + "=" + result);
}else if(alreadyDisplayed.charAt(i)=='/'){
result = Double.parseDouble(alreadyDisplayed.substring(0,i)) / Double.parseDouble(alreadyDisplayed.substring(i+1,alreadyDisplayed.length()));
tf.setText(alreadyDisplayed + "=" + result);
}else if(alreadyDisplayed.charAt(i)=='*'){
result = Double.parseDouble(alreadyDisplayed.substring(0,i)) * Double.parseDouble(alreadyDisplayed.substring(i+1,alreadyDisplayed.length()));
tf.setText(alreadyDisplayed + "=" + result);
}
}
}
}
}
}
我遇到困难的部分是获取一个数字并存储它，以便我可以让用户输入两个以上的值。因此，例如，如果我在上面代码的末尾取出for循环并用它替换它;
double []num1=new double[10];
double []num2=new double[10];
//double num1 = 0;
double temp =0;
String str[] = new String [10];
String []str1 = new String[10];
if(e.getActionCommand().equals("+"))
if(e.getSource() == opButtonEquals)
for( int i = 0; i<alreadyDisplayed.length(); i++){
if(alreadyDisplayed.charAt(i)=='+')
str[i] = alreadyDisplayed.substring(0,i);
num1[i] = Double.parseDouble(str[i]);
str1[i+1] = alreadyDisplayed.substring(i+1,alreadyDisplayed.length());
num2[i+1] = Double.parseDouble(str1[i]);
temp += num1[i] + num2[i+1];
tf.setText(Double.toString(temp));
}System.out.println(temp);
}
}
因此，当我尝试测试temp是否在控制台中有任何值时，它每次只打印0。字符串文本显示在文本字段中，但是没有实际的计算工作。我认为这可以通过存储一个数字，然后存储另一个数字，然后将它们加在一起，但它没有。
答案 0 :(得分：0)
为什么不将值存储到字符串中（更容易操作），然后再将其解析为算术表达式？例如..
人按下按钮“（”，“sin（8）”，“+”，“8”，“）”，“+”，“1”，“=”
快速评估为一个简单的字符串（sin（8）+8）+1 =
您可以解析字符串并查找需要解析的明显事物（例如，查找sin，然后递归地解析括号之间的所有内容）。使用Math函数来计算复杂表达式，并解析简单表达式。
我可能会建议您编写自己的函数来解决复杂的表达式 - 类似于此......
public double solveSin(String inside) {
if(NumberUtils.isNumber(inside)) {
return Math.sin(Double.parseDouble(inside);
} else {
//Call back to original function to direct based on inputs
return Math.sin(parseEquation(inside));
}
}
答案 1 :(得分：0)
尝试按下按钮后立即生成操作员树。按下更多按钮，继续更新树。解析整个方程式字符串可能是一项艰巨的任务。
用户按Enter后，解决您的运算符树。这有很多好处。 1）您不必一次处理解析一个操作数/运算符。 2）正确的有序树遍历将处理BODMAS规则和数学运算符的其他细节。 3）有序遍历将为您提供用户输入的原始等式，您可以将其显示回来。