简单的 GUI Java 计算器
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Simple GUI Java calculator
提问by Carlos_Gomez
I am building a simple GUI Java calculator. I have an issue finding a package or figuring out a method to do the actual calculation. So far I've figured that when I do a math operation, the number in the text box gets saved in a temporary location.
我正在构建一个简单的 GUI Java 计算器。我在寻找包或找出进行实际计算的方法时遇到问题。到目前为止，我认为当我进行数学运算时，文本框中的数字会保存在一个临时位置。
Then when I click on the "="button, it will do the calculation, but I don't know how to tell it to take the temporary plus the math operation and the second number and do the calculation based on the selected math operation clicked, +, -, *, /
然后当我单击"="按钮时，它会进行计算，但我不知道如何告诉它取临时加上数学运算和第二个数字，并根据单击的选定数学运算进行计算，+, -, *, /
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
public class JavaCalculator extends JFrame {
private JButton jbtNum1;
private JButton jbtNum2;
private JButton jbtNum3;
private JButton jbtNum4;
private JButton jbtNum5;
private JButton jbtNum6;
private JButton jbtNum7;
private JButton jbtNum8;
private JButton jbtNum9;
private JButton jbtNum0;
private JButton jbtEqual;
private JButton jbtAdd;
private JButton jbtSubtract;
private JButton jbtMultiply;
private JButton jbtDivide;
private JButton jbtSolve;
private JButton jbtClear;
private double TEMP;
private double SolveTEMP;
private JTextField jtfResult;
String display = "";
public JavaCalculator() {
JPanel p1 = new JPanel();
p1.setLayout(new GridLayout(4, 3));
p1.add(jbtNum1 = new JButton("1"));
p1.add(jbtNum2 = new JButton("2"));
p1.add(jbtNum3 = new JButton("3"));
p1.add(jbtNum4 = new JButton("4"));
p1.add(jbtNum5 = new JButton("5"));
p1.add(jbtNum6 = new JButton("6"));
p1.add(jbtNum7 = new JButton("7"));
p1.add(jbtNum8 = new JButton("8"));
p1.add(jbtNum9 = new JButton("9"));
p1.add(jbtNum0 = new JButton("0"));
p1.add(jbtClear = new JButton("C"));
JPanel p2 = new JPanel();
p2.setLayout(new FlowLayout());
p2.add(jtfResult = new JTextField(20));
jtfResult.setHorizontalAlignment(JTextField.RIGHT);
jtfResult.setEditable(false);
JPanel p3 = new JPanel();
p3.setLayout(new GridLayout(5, 1));
p3.add(jbtAdd = new JButton("+"));
p3.add(jbtSubtract = new JButton("-"));
p3.add(jbtMultiply = new JButton("*"));
p3.add(jbtDivide = new JButton("/"));
p3.add(jbtSolve = new JButton("="));
JPanel p = new JPanel();
p.setLayout(new GridLayout());
p.add(p2, BorderLayout.NORTH);
p.add(p1, BorderLayout.SOUTH);
p.add(p3, BorderLayout.EAST);
add(p);
jbtNum1.addActionListener(new ListenToOne());
jbtNum2.addActionListener(new ListenToTwo());
jbtNum3.addActionListener(new ListenToThree());
jbtNum4.addActionListener(new ListenToFour());
jbtNum5.addActionListener(new ListenToFive());
jbtNum6.addActionListener(new ListenToSix());
jbtNum7.addActionListener(new ListenToSeven());
jbtNum8.addActionListener(new ListenToEight());
jbtNum9.addActionListener(new ListenToNine());
jbtNum0.addActionListener(new ListenToZero());
jbtAdd.addActionListener(new ListenToAdd());
jbtSubtract.addActionListener(new ListenToSubtract());
jbtMultiply.addActionListener(new ListenToMultiply());
jbtDivide.addActionListener(new ListenToDivide());
jbtSolve.addActionListener(new ListenToSolve());
} //JavaCaluclator()
class ListenToOne implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "1");
}
}
class ListenToTwo implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "2");
}
}
class ListenToThree implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "3");
}
}
class ListenToFour implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "4");
}
}
class ListenToFive implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "5");
}
}
class ListenToSix implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "6");
}
}
class ListenToSeven implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "7");
}
}
class ListenToEight implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "8");
}
}
class ListenToNine implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "9");
}
}
class ListenToZero implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "0");
}
}
class ListenToAdd implements ActionListener {
public void actionPerformed(ActionEvent e) {
TEMP = Double.parseDouble(jtfResult.getText());
jtfResult.setText("");
}
}
class ListenToSubtract implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "0");
}
}
class ListenToMultiply implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "0");
}
}
class ListenToDivide implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "0");
}
}
class ListenToSolve implements ActionListener {
public void actionPerformed(ActionEvent e) {
SolveTEMP = jtfResult.getText();
jtfResult.setText(TEMP + Double.parseDouble(jtfResult);
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
JavaCalculator calc = new JavaCalculator();
calc.pack();
calc.setLocationRelativeTo(null);
calc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
calc.setVisible(true);
}
} //JavaCalculator
回答by Ivo Wetzel
What you need is something that calculates the result of the infix notatedcalculation, have a look at the Shunting-Yard Algorithm.
你需要的是计算中缀符号计算结果的东西，看看Shunting-Yard Algorithm。
There's an example in C++ on Wikipedia's page, but it shouldn't be too hard to implement it in Java.
And since it's the primary function of your calculator, I would advise you to not grab some codezfrom the Web in this Case (except all you want to do is building calculator GUIs).
维基百科页面上有一个 C++ 示例，但在 Java 中实现它应该不会太难。
由于它是计算器的主要功能，因此在这种情况下，我建议您不要从 Web 上获取一些代码（除非您想做的只是构建计算器 GUI）。
回答by Loduwijk
Somewhere you have to keep track of what button had been pressed. When things happen, you need to store something in a variable so you can recall the information or it's gone forever.
您必须在某处跟踪按下了哪个按钮。当事情发生时，你需要将一些东西存储在一个变量中，这样你就可以回忆起这些信息，否则它就永远消失了。
When someone pressed one of the operator buttons, don't just let them type in another value. Save the operator symbol, then let them type in another value. You could literally just have a String operatorthat gets the text of the operator button pressed. Then, when the equals button is pressed, you have to check to see which operator you stored. You could do this with an if/else if/else chain.
当有人按下操作员按钮之一时，不要让他们输入另一个值。保存运算符符号，然后让他们输入另一个值。从字面上看，您可以拥有一个String operator按下操作员按钮的文本。然后，当按下等于按钮时，您必须检查您存储的运算符。您可以使用 if/else if/else 链来执行此操作。
So, in your symbol's button press event, store the symbol text in a variable, then, in the = button press event, check to see which symbol is in the variable and act accordingly.
因此，在您的符号的按钮按下事件中，将符号文本存储在一个变量中，然后，在 = 按钮按下事件中，检查变量中的哪个符号并采取相应的行动。
Alternatively, if you feel comfortable enough with enums (looks like you're just starting, so if you're not to that point yet, ignore this), you could have an enumeration of symbols that lets you check symbols easily with a switch.
或者，如果您对枚举感到足够满意（看起来您才刚刚开始，所以如果您还没有达到这一点，请忽略这一点），您可以拥有一个符号枚举，让您可以轻松地使用开关检查符号。
回答by Gian Santillan
assuming that string1 is your whole operation
假设 string1 是你的整个操作
use mdas
使用 mda
double result;
string recurAndCheck(string operation){
if(operation.indexOf("/")){
String leftSide = recurAndCheck(operation.split("/")[0]);
string rightSide = recurAndCheck(operation.split("/")[1]);
result = Double.parseDouble(leftSide)/Double.parseDouble(rightSide);
} else if (..continue w/ *...) {
//same as above but change / with *
} else if (..continue w/ -) {
//change as above but change with -
} else if (..continuew with +) {
//change with add
} else {
return;
}
}
回答by Aamir Abro
This is the working code...
这是工作代码...
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
public class JavaCalculator extends JFrame {
private JButton jbtNum1;
private JButton jbtNum2;
private JButton jbtNum3;
private JButton jbtNum4;
private JButton jbtNum5;
private JButton jbtNum6;
private JButton jbtNum7;
private JButton jbtNum8;
private JButton jbtNum9;
private JButton jbtNum0;
private JButton jbtEqual;
private JButton jbtAdd;
private JButton jbtSubtract;
private JButton jbtMultiply;
private JButton jbtDivide;
private JButton jbtSolve;
private JButton jbtClear;
private double TEMP;
private double SolveTEMP;
private JTextField jtfResult;
Boolean addBool = false;
Boolean subBool = false;
Boolean divBool = false;
Boolean mulBool = false;
String display = "";
public JavaCalculator() {
JPanel p1 = new JPanel();
p1.setLayout(new GridLayout(4, 3));
p1.add(jbtNum1 = new JButton("1"));
p1.add(jbtNum2 = new JButton("2"));
p1.add(jbtNum3 = new JButton("3"));
p1.add(jbtNum4 = new JButton("4"));
p1.add(jbtNum5 = new JButton("5"));
p1.add(jbtNum6 = new JButton("6"));
p1.add(jbtNum7 = new JButton("7"));
p1.add(jbtNum8 = new JButton("8"));
p1.add(jbtNum9 = new JButton("9"));
p1.add(jbtNum0 = new JButton("0"));
p1.add(jbtClear = new JButton("C"));
JPanel p2 = new JPanel();
p2.setLayout(new FlowLayout());
p2.add(jtfResult = new JTextField(20));
jtfResult.setHorizontalAlignment(JTextField.RIGHT);
jtfResult.setEditable(false);
JPanel p3 = new JPanel();
p3.setLayout(new GridLayout(5, 1));
p3.add(jbtAdd = new JButton("+"));
p3.add(jbtSubtract = new JButton("-"));
p3.add(jbtMultiply = new JButton("*"));
p3.add(jbtDivide = new JButton("/"));
p3.add(jbtSolve = new JButton("="));
JPanel p = new JPanel();
p.setLayout(new GridLayout());
p.add(p2, BorderLayout.NORTH);
p.add(p1, BorderLayout.SOUTH);
p.add(p3, BorderLayout.EAST);
add(p);
jbtNum1.addActionListener(new ListenToOne());
jbtNum2.addActionListener(new ListenToTwo());
jbtNum3.addActionListener(new ListenToThree());
jbtNum4.addActionListener(new ListenToFour());
jbtNum5.addActionListener(new ListenToFive());
jbtNum6.addActionListener(new ListenToSix());
jbtNum7.addActionListener(new ListenToSeven());
jbtNum8.addActionListener(new ListenToEight());
jbtNum9.addActionListener(new ListenToNine());
jbtNum0.addActionListener(new ListenToZero());
jbtAdd.addActionListener(new ListenToAdd());
jbtSubtract.addActionListener(new ListenToSubtract());
jbtMultiply.addActionListener(new ListenToMultiply());
jbtDivide.addActionListener(new ListenToDivide());
jbtSolve.addActionListener(new ListenToSolve());
jbtClear.addActionListener(new ListenToClear());
} //JavaCaluclator()
class ListenToClear implements ActionListener {
public void actionPerformed(ActionEvent e) {
//display = jtfResult.getText();
jtfResult.setText("");
addBool = false;
subBool = false;
mulBool = false;
divBool = false;
TEMP = 0;
SolveTEMP = 0;
}
}
class ListenToOne implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "1");
}
}
class ListenToTwo implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "2");
}
}
class ListenToThree implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "3");
}
}
class ListenToFour implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "4");
}
}
class ListenToFive implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "5");
}
}
class ListenToSix implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "6");
}
}
class ListenToSeven implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "7");
}
}
class ListenToEight implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "8");
}
}
class ListenToNine implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "9");
}
}
class ListenToZero implements ActionListener {
public void actionPerformed(ActionEvent e) {
display = jtfResult.getText();
jtfResult.setText(display + "0");
}
}
class ListenToAdd implements ActionListener {
public void actionPerformed(ActionEvent e) {
TEMP = Double.parseDouble(jtfResult.getText());
jtfResult.setText("");
addBool = true;
}
}
class ListenToSubtract implements ActionListener {
public void actionPerformed(ActionEvent e) {
TEMP = Double.parseDouble(jtfResult.getText());
jtfResult.setText("");
subBool = true;
}
}
class ListenToMultiply implements ActionListener {
public void actionPerformed(ActionEvent e) {
TEMP = Double.parseDouble(jtfResult.getText());
jtfResult.setText("");
mulBool = true;
}
}
class ListenToDivide implements ActionListener {
public void actionPerformed(ActionEvent e) {
TEMP = Double.parseDouble(jtfResult.getText());
jtfResult.setText("");
divBool = true;
}
}
class ListenToSolve implements ActionListener {
public void actionPerformed(ActionEvent e) {
SolveTEMP = Double.parseDouble(jtfResult.getText());
if (addBool == true)
SolveTEMP = SolveTEMP + TEMP;
else if ( subBool == true)
SolveTEMP = SolveTEMP - TEMP;
else if ( mulBool == true)
SolveTEMP = SolveTEMP * TEMP;
else if ( divBool == true)
SolveTEMP = SolveTEMP / TEMP;
jtfResult.setText( Double.toString(SolveTEMP));
addBool = false;
subBool = false;
mulBool = false;
divBool = false;
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
JavaCalculator calc = new JavaCalculator();
calc.pack();
calc.setLocationRelativeTo(null);
calc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
calc.setVisible(true);
}
} //JavaCalculator
